@@ -1,7 +1,8 @@
11use std::collections::HashMap;
2−use std::hash::{Hash, Hasher};
2+use std::hash::Hash;
33
44use crate::ast::*;
5+use crate::vocab::with_px;
56
67// ---------------------------------------------------------------------------
78// Style collector: deduplicates CSS and assigns class names
@@ -16,56 +17,315 @@ const BREAKPOINTS: &[(&str, &str)] = &[
1617 ("2xl", "1536px"),
1718];
1819
19−/// Generate short CSS class names: a..z, then aa..a9, ba..b9, ..., z9, then
20−/// aaa, ... The first character is always a letter; later ones are drawn from
21−/// [a-z0-9]. The mapping is a bijection, so distinct indices never collide.
22−pub(crate) fn short_class_name(idx: usize) -> String {
23− const REST: &[u8] = b"abcdefghijklmnopqrstuvwxyz0123456789";
24− // Find the name length: 26 names of length 1, 26*36 of length 2, ...
25− let mut n = idx;
26− let mut len = 1;
27− let mut count = 26usize;
28− while n >= count {
29− n -= count;
30− len += 1;
31− count = count.saturating_mul(36);
32− }
33− let mut tail = Vec::with_capacity(len - 1);
34− for _ in 1..len {
35− tail.push(REST[n % 36]);
36− n /= 36;
37− }
38− let mut name = String::with_capacity(len);
39− name.push((b'a' + n as u8) as char);
40− name.extend(tail.iter().rev().map(|&b| b as char));
41− name
20+/// The prefix of every generated class (`hl-2k9xq0m`), which keeps them
21+/// out of the author's own class names.
22+pub const CLASS_PREFIX: &str = "hl-";
23+
24+/// How many base-36 digits a class's name has after `hl-`: 7, about 36
25+/// bits of its style's hash, so a site with 10,000 different styles has
26+/// odds of about 6 in 10,000 that two of them share a name, which
27+/// `htmlang build` reports (`class-collision`). Within one file, a style
28+/// whose name is taken takes more digits.
29+pub const CLASS_DIGITS: usize = 7;
30+
31+/// A stable hash of `text`: FNV-1a, then SplitMix64's finalizer, so every
32+/// digit of a name depends on all of the text. It is the same on every
33+/// platform and in every build, unlike `std`'s hasher.
34+pub fn stable_hash(text: &str) -> u64 {
35+ let mut hash: u64 = 0xcbf2_9ce4_8422_2325;
36+ for byte in text.bytes() {
37+ hash ^= u64::from(byte);
38+ hash = hash.wrapping_mul(0x0000_0100_0000_01b3);
39+ }
40+ hash = (hash ^ (hash >> 30)).wrapping_mul(0xbf58_476d_1ce4_e5b9);
41+ hash = (hash ^ (hash >> 27)).wrapping_mul(0x94d0_49bb_1331_11eb);
42+ hash ^ (hash >> 31)
43+}
44+
45+/// `digits` base-36 digits of `hash`: `2k9xq0m`. With 13, all of it.
46+pub fn hash_digits(hash: u64, digits: usize) -> String {
47+ const DIGITS: &[u8] = b"0123456789abcdefghijklmnopqrstuvwxyz";
48+ let mut n = hash;
49+ (0..digits)
50+ .map(|_| {
51+ let digit = DIGITS[(n % 36) as usize] as char;
52+ n /= 36;
53+ digit
54+ })
55+ .collect()
56+}
57+
58+/// A class htmlang generated: its name, and the hash of the style it
59+/// stands for. One style has one name in every file, so a fragment's
60+/// classes mean the same in any page it goes into.
61+#[derive(Clone, Debug, PartialEq, Eq)]
62+pub struct Class {
63+ pub name: String,
64+ pub style: u64,
65+}
66+
67+/// When a style applies: the at-rule prefixes it is under (their ranks,
68+/// see [`crate::vocab::at_rule_rank`], sorted, so `dark:md:` and `md:dark:`
69+/// are one condition) and its selector prefixes, left to right as the
70+/// selector reads (`hover:children:` is `.a:hover > *`).
71+#[derive(Clone, Default, PartialEq, Eq, Hash, Debug)]
72+struct Condition {
73+ at: Vec<usize>,
74+ selector: Vec<String>,
75+}
76+
77+impl Condition {
78+ /// The condition of an attribute's key, and the name after its
79+ /// prefixes.
80+ fn of(key: &str) -> (Condition, &str) {
81+ let (prefixes, name) = crate::vocab::split_prefixes(key);
82+ let mut condition = Condition::default();
83+ for prefix in prefixes {
84+ match crate::vocab::at_rule_rank(prefix) {
85+ Some(rank) => condition.at.push(rank),
86+ None => condition.selector.push(prefix.to_string()),
87+ }
88+ }
89+ condition.at.sort_unstable();
90+ condition.at.dedup();
91+ (condition, name)
92+ }
93+
94+ /// Only the at-rule part: a direction under `hover:` is the one without
95+ /// it.
96+ fn at_only(at: &[usize]) -> Condition {
97+ Condition {
98+ at: at.to_vec(),
99+ selector: Vec::new(),
100+ }
101+ }
102+
103+ /// The styles go on the element's children (`children:`).
104+ fn on_children(&self) -> bool {
105+ self.selector.iter().any(|p| p == crate::vocab::CHILDREN)
106+ }
107+
108+ /// The styles go on the elements of one kind inside the element
109+ /// (`@td:`): where the element prefix is in the selector chain.
110+ fn inside(&self) -> Option<usize> {
111+ self.selector
112+ .iter()
113+ .position(|p| crate::vocab::element_prefix(p).is_some())
114+ }
115+
116+ /// Whether this condition holds wherever `other` does: its at-rules
117+ /// are implied by `other`'s, and it has no selector or `other`'s.
118+ fn holds_at(&self, other: &Condition) -> bool {
119+ (self.selector.is_empty() || self.selector == other.selector)
120+ && self.at.iter().all(|&a| {
121+ other
122+ .at
123+ .iter()
124+ .any(|&b| crate::vocab::at_rule_implied(a, b))
125+ })
126+ }
127+
128+ /// The order the rules of each condition are written in, which the
129+ /// cascade follows: no prefix, then selectors, then each at-rule
130+ /// block (see [`at_order`]), with its selectors inside it.
131+ fn order(&self) -> (AtOrder, SelectorOrder) {
132+ (at_order(&self.at), selector_order(&self.selector))
133+ }
134+}
135+
136+/// Where a block of at-rules is written: after the rules without one; by
137+/// its last (innermost) prefix in the order of
138+/// [`crate::vocab::at_rule_prefixes`] (widths, media, container widths), so
139+/// `md:dark:` comes with `dark:`, after it; then by length.
140+type AtOrder = (bool, usize, usize, Vec<usize>);
141+
142+fn at_order(at: &[usize]) -> AtOrder {
143+ (
144+ !at.is_empty(),
145+ at.last().copied().unwrap_or(0),
146+ at.len(),
147+ at.to_vec(),
148+ )
149+}
150+
151+/// Selector chains in the order of [`crate::vocab::PSEUDOS`] (position,
152+/// then form state, then `hover:`, `focus:`, `active:`, `disabled:`), and
153+/// by their argument's text for the same pseudo-class; a chain before the
154+/// longer ones it starts. A chain through `children:` comes after the
155+/// others, ordered by what follows its last `children:` and then by what
156+/// comes before it: only that tail counts toward its specificity (see
157+/// [`selector`]), so `hover:children:` follows `children:` and wins over it
158+/// on hover.
159+type SelectorOrder = (bool, Vec<(usize, String)>, Vec<(usize, String)>);
160+
161+fn selector_order(selector: &[String]) -> SelectorOrder {
162+ let table = crate::vocab::PSEUDOS;
163+ let ranked = |chain: &[String]| -> Vec<(usize, String)> {
164+ chain
165+ .iter()
166+ .map(|p| {
167+ let name = crate::vocab::pseudo_name(p);
168+ let rank = table
169+ .iter()
170+ .position(|(q, _)| *q == name)
171+ .unwrap_or(table.len());
172+ (rank, p.clone())
173+ })
174+ .collect()
175+ };
176+ match selector.iter().rposition(|p| p == crate::vocab::CHILDREN) {
177+ None => (false, ranked(selector), Vec::new()),
178+ Some(i) => (true, ranked(&selector[i + 1..]), ranked(&selector[..i])),
179+ }
180+}
181+
182+/// The order of the chains through an element prefix (`@td:`, see
183+/// [`scoped_selector`]): by the prefixes before it, which select the root
184+/// of the scope and add nothing to the specificity, so `hover:@td:` comes
185+/// after `@td:` and wins on hover; then by the element; then by the
186+/// prefixes after it.
187+fn inside_order(chain: &[String]) -> (SelectorOrder, String, SelectorOrder) {
188+ let at = chain
189+ .iter()
190+ .position(|p| crate::vocab::element_prefix(p).is_some())
191+ .unwrap_or(chain.len());
192+ (
193+ selector_order(&chain[..at]),
194+ chain.get(at).cloned().unwrap_or_default(),
195+ selector_order(chain.get(at + 1..).unwrap_or_default()),
196+ )
197+}
198+
199+/// The selector for `class` under a chain of selector prefixes, read left
200+/// to right. Everything before the last `children:` goes in `:where()`, so
201+/// a parent's `children:` styles have no specificity, and a child's own
202+/// attributes win over them: `children:hover:` is `:where(.a)>*:hover`,
203+/// `hover:children:` is `:where(.a:hover)>*`.
204+fn selector(class: &str, chain: &[String]) -> String {
205+ let last_children = chain.iter().rposition(|p| p == crate::vocab::CHILDREN);
206+ let mut out = format!(".{}", class);
207+ for (i, prefix) in chain.iter().enumerate() {
208+ if prefix == crate::vocab::CHILDREN {
209+ if Some(i) == last_children {
210+ out = format!(":where({})>*", out);
211+ } else {
212+ out.push_str(">*");
213+ }
214+ } else if let Some(pseudo) = crate::vocab::pseudo_selector(prefix) {
215+ out.push_str(&pseudo);
216+ }
217+ }
218+ out
219+}
220+
221+/// The rule for the elements an element prefix picks out inside the
222+/// element with the class `class` (see [`Condition::inside`]): the scope's
223+/// root, from the selector prefixes before it (`hover:@td:` is inside a
224+/// hovered element), and the selector for the elements, from those after
225+/// it (`@td:hover:` is a hovered cell). `:scope td` leaves out the root
226+/// itself, so `@ul [@ul:...]` styles the lists inside, not its own. `None`
227+/// when the name has no tag of its own (the parser reports it).
228+fn scoped_selector(class: &str, chain: &[String], at: usize) -> Option<(String, String)> {
229+ let name = crate::vocab::element_prefix(&chain[at])?;
230+ let tag = ElementKind::from_name(name)?.own_tag()?;
231+ let root = selector(class, &chain[..at]);
232+ let mut target = format!(":scope {}", tag);
233+ for prefix in &chain[at + 1..] {
234+ if let Some(pseudo) = crate::vocab::pseudo_selector(prefix) {
235+ target.push_str(&pseudo);
236+ }
237+ }
238+ Some((root, target))
239+}
240+
241+/// The `@media` or `@container` rule an at-rule prefix stands for, as
242+/// written in readable and in compact output.
243+fn at_rule(rank: usize, dev: bool) -> String {
244+ let prefix = crate::vocab::at_rule_prefixes()
245+ .nth(rank)
246+ .unwrap_or_default();
247+ let name = prefix.trim_end_matches(':');
248+ let width = |name: &str| {
249+ BREAKPOINTS
250+ .iter()
251+ .find(|(n, _)| *n == name)
252+ .map_or("0", |(_, w)| *w)
253+ };
254+ let (kind, feature, value) = if let Some(size) = name.strip_prefix("cq-") {
255+ ("@container", "min-width", width(size))
256+ } else {
257+ match name {
258+ "print" => {
259+ return "@media print".to_string();
260+ }
261+ "dark" => ("@media", "prefers-color-scheme", "dark"),
262+ "motion-safe" => ("@media", "prefers-reduced-motion", "no-preference"),
263+ "motion-reduce" => ("@media", "prefers-reduced-motion", "reduce"),
264+ "landscape" | "portrait" => ("@media", "orientation", name),
265+ _ => ("@media", "min-width", width(name)),
266+ }
267+ };
268+ if dev {
269+ format!("{} ({}: {})", kind, feature, value)
270+ } else {
271+ format!("{}({}:{})", kind, feature, value)
272+ }
273+}
274+
275+/// A style as text, for its hash: the defaults of its element's kind, its
276+/// rules (the at-rules' ranks, the selector prefixes and the declarations
277+/// of each) and the rules keyed on it, each part ended by a character CSS
278+/// doesn't have.
279+fn style_text(defaults: &str, rules: &[(Condition, String)], distinct: &str) -> String {
280+ let mut text = format!("{defaults}\u{1}");
281+ for (condition, body) in rules {
282+ for rank in &condition.at {
283+ text.push_str(&format!("{rank}\u{2}"));
284+ }
285+ text.push('\u{3}');
286+ for prefix in &condition.selector {
287+ text.push_str(prefix);
288+ text.push('\u{2}');
289+ }
290+ text.push('\u{3}');
291+ text.push_str(body);
292+ text.push('\u{1}');
293+ }
294+ text.push_str(distinct);
295+ text
42296}
43297
44298struct StyleEntry {
45299 class_name: String,
46− base: String,
47− /// (CSS selector suffix, css_rules) — e.g. (":hover", "color:red;")
48− pseudo: Vec<(String, String)>,
49− /// Responsive overrides: (breakpoint_prefix, css)
50− responsive: Vec<(String, String)>,
51− /// Dark mode overrides
52− dark: String,
53− /// Print overrides
54− print: String,
55− motion_safe: String,
56− motion_reduce: String,
57− landscape: String,
58− portrait: String,
59− /// Container query overrides: (breakpoint_prefix, css)
60− container: Vec<(String, String)>,
300+ /// The hash of the style, which names the class
301+ style: u64,
302+ /// The defaults of the element's kind (its layout, a heading's
303+ /// `margin:0`, ...), less what its own attributes set. They are written
304+ /// as `:where(.hl-a)` in the layer `hl-kind`, so an element prefix
305+ /// around it (`@h2:`), its parent's `children:` styles and its own
306+ /// attributes, all in later layers, win over them.
307+ defaults: String,
308+ /// The element's rules: under each condition, its declarations, in the
309+ /// order they are written
310+ rules: Vec<(Condition, String)>,
311+ /// What else tells two elements with the same CSS apart: the rules
312+ /// keyed on this class (see [`StyleCollector::keyed`]). Not written.
313+ distinct: String,
61314}
62315
63316struct StyleCollector {
64317 entries: Vec<StyleEntry>,
65− /// Maps a pre-hashed style signature to an index into `entries`.
66− /// Using u64 as the key keeps lookups allocation-free; on the rare case of
67− /// a hash collision we fall back to a full equality check against the entry.
318+ /// Maps a style's hash to its entries (more than one only when two
319+ /// styles hash alike, which the full comparison tells apart).
68320 index: HashMap<u64, Vec<usize>>,
321+ /// The names given, which a style whose name is taken doesn't get
322+ names: std::collections::HashSet<String>,
323+ /// Rules for an element's children, keyed on its class and written in
324+ /// the block of an at-rule condition: `(at-rules, selector, body)`, e.g.
325+ /// `([md], ":where(.a)>.b", "flex:1;")` (see [`Flow`]).
326+ keyed: Vec<(Vec<usize>, String, String)>,
327+ /// The keyed rules already added
328+ keyed_seen: std::collections::HashSet<(Vec<usize>, String, String)>,
69329}
70330
71331impl StyleCollector {
@@ -73,313 +333,282 @@ impl StyleCollector {
73333 StyleCollector {
74334 entries: Vec::new(),
75335 index: HashMap::new(),
336+ names: std::collections::HashSet::new(),
337+ keyed: Vec::new(),
338+ keyed_seen: std::collections::HashSet::new(),
339+ }
340+ }
341+
342+ /// Add a rule for `selector` under the at-rules `at`, once.
343+ fn add_keyed(&mut self, at: Vec<usize>, selector: String, body: String) {
344+ let rule = (at, selector, body);
345+ if self.keyed_seen.insert(rule.clone()) {
346+ self.keyed.push(rule);
76347 }
77348 }
78349
79350 /// Returns a class name for this style combination, or None if all empty.
80− #[allow(clippy::too_many_arguments)]
81351 fn get_class(
82352 &mut self,
83− base: String,
84− pseudo: Vec<(String, String)>,
85− responsive: Vec<(String, String)>,
86− dark: String,
87− print: String,
88− motion_safe: String,
89− motion_reduce: String,
90− landscape: String,
91− portrait: String,
92− container: Vec<(String, String)>,
353+ defaults: String,
354+ mut rules: Vec<(Condition, String)>,
355+ distinct: String,
93356 ) -> Option<String> {
94− if base.is_empty()
95− && pseudo.is_empty()
96− && responsive.is_empty()
97− && dark.is_empty()
98− && print.is_empty()
99− && motion_safe.is_empty()
100− && motion_reduce.is_empty()
101− && landscape.is_empty()
102− && portrait.is_empty()
103− && container.is_empty()
104− {
357+ rules.retain(|(_, body)| !body.is_empty());
358+ if defaults.is_empty() && rules.is_empty() {
105359 return None;
106360 }
107− use std::collections::hash_map::DefaultHasher;
108− let mut h = DefaultHasher::new();
109− base.hash(&mut h);
110− pseudo.hash(&mut h);
111− responsive.hash(&mut h);
112− dark.hash(&mut h);
113− print.hash(&mut h);
114− motion_safe.hash(&mut h);
115− motion_reduce.hash(&mut h);
116− landscape.hash(&mut h);
117− portrait.hash(&mut h);
118− container.hash(&mut h);
119− let sig = h.finish();
120−
121− if let Some(indices) = self.index.get(&sig) {
361+ rules.sort_by_cached_key(|(condition, _)| condition.order());
362+ let style = stable_hash(&style_text(&defaults, &rules, &distinct));
363+
364+ if let Some(indices) = self.index.get(&style) {
122365 for &idx in indices {
123366 let e = &self.entries[idx];
124− if e.base == base
125− && e.pseudo == pseudo
126− && e.responsive == responsive
127− && e.dark == dark
128− && e.print == print
129− && e.motion_safe == motion_safe
130− && e.motion_reduce == motion_reduce
131− && e.landscape == landscape
132− && e.portrait == portrait
133− && e.container == container
134− {
367+ if e.defaults == defaults && e.rules == rules && e.distinct == distinct {
135368 return Some(e.class_name.clone());
136369 }
137370 }
138371 }
372+ // The name is the hash's first digits, and more of them when
373+ // another style of this file has those; after all 13, the entry's
374+ // number tells the two apart
139375 let idx = self.entries.len();
140− let name = short_class_name(idx);
376+ let name = (CLASS_DIGITS..=13)
377+ .map(|digits| format!("{}{}", CLASS_PREFIX, hash_digits(style, digits)))
378+ .find(|name| !self.names.contains(name))
379+ .unwrap_or_else(|| format!("{}{}{}", CLASS_PREFIX, hash_digits(style, 13), idx));
380+ self.names.insert(name.clone());
141381 self.entries.push(StyleEntry {
142382 class_name: name.clone(),
143− base,
144− pseudo,
145− responsive,
146− dark,
147− print,
148− motion_safe,
149− motion_reduce,
150− landscape,
151− portrait,
152− container,
383+ style,
384+ defaults,
385+ rules,
386+ distinct,
153387 });
154− self.index.entry(sig).or_default().push(idx);
388+ self.index.entry(style).or_default().push(idx);
155389 Some(name)
156390 }
157391
158− /// All generated rules, wrapped in `@layer htmlang`.
159− fn to_css_formatted(&self, dev: bool) -> String {
160− let mut css = String::new();
161− let inner_indent = if dev { " " } else { "" };
162− css.push_str(if dev { "@layer htmlang {\n" } else { "@layer htmlang{" });
163−
164− // Non-responsive rules. Base and pseudo rules are merged separately by
165− // identical body so that e.g. `.a,.b{display:flex;flex-direction:column;}`
166− // replaces two identical rules. Pseudo variants are grouped per selector
167− // suffix (`:hover` with `:hover`, etc.) to keep each pseudo's cascade
168− // position independent of others.
169− let mut base_pairs: Vec<(&str, &str)> = Vec::with_capacity(self.entries.len());
170− for e in &self.entries {
171− if !e.base.is_empty() {
172− base_pairs.push((e.class_name.as_str(), e.base.as_str()));
392+ /// The classes given, in the order they were
393+ fn classes(&self) -> impl Iterator<Item = Class> + '_ {
394+ self.entries.iter().map(|e| Class {
395+ name: e.class_name.clone(),
396+ style: e.style,
397+ })
398+ }
399+
400+ /// All generated rules, in three layers (see [`LAYERS`]): the element
401+ /// kinds' defaults in `hl-kind` (`:where(.hl-a)`), the rules for the
402+ /// elements an element prefix picks out inside an element (`@td:`), and
403+ /// a function's scoped `@style`, in `hl-inside`, and the elements' own
404+ /// rules in `htmlang`. They are written in a fixed order, so which rule
405+ /// wins never depends on where in the page an element is: the rules
406+ /// without a prefix, then those under selector prefixes, then each block
407+ /// of at-rules (see [`at_order`]), in which the rules keyed on a parent
408+ /// come first, then the element's own, then its selectors (see
409+ /// [`selector_order`]).
410+ fn to_css_formatted(&self, dev: bool, scoped: &[String]) -> String {
411+ // The defaults: `:where(.hl-a,.hl-b){...}`
412+ let mut kind = String::new();
413+ let mut defaults: Vec<(&str, Vec<&str>)> = Vec::new();
414+ for e in self.entries.iter().filter(|e| !e.defaults.is_empty()) {
415+ match defaults.iter_mut().find(|(body, _)| *body == e.defaults) {
416+ Some((_, classes)) => classes.push(&e.class_name),
417+ None => defaults.push((&e.defaults, vec![&e.class_name])),
418+ }
419+ }
420+ for (body, classes) in defaults {
421+ let classes: Vec<String> = classes.iter().map(|c| format!(".{}", c)).collect();
422+ let selector = format!(":where({})", classes.join(","));
423+ if dev {
424+ kind.push_str(&format!(" {} {{{}}}\n", selector, body));
425+ } else {
426+ kind.push_str(&format!("{}{{{}}}", selector, body));
173427 }
174428 }
175− emit_grouped_rules(&mut css, &base_pairs, "", inner_indent, dev);
176429
177− // Collect pseudo rules grouped by selector suffix, preserving the order
178− // in which suffixes first appear across entries.
179− let mut pseudo_order: Vec<&str> = Vec::new();
180− let mut pseudo_buckets: HashMap<&str, Vec<(&str, &str)>> = HashMap::new();
181− for e in &self.entries {
182− for (selector, body) in &e.pseudo {
183− if body.is_empty() {
184− continue;
185− }
186− let key = selector.as_str();
187− if !pseudo_buckets.contains_key(key) {
188− pseudo_order.push(key);
189− }
190− pseudo_buckets
191− .entry(key)
192− .or_default()
193− .push((e.class_name.as_str(), body.as_str()));
430+ let mut inside = self.blocks(true, dev);
431+ // A function's scoped `@style`, nested under its class
432+ for block in scoped {
433+ if dev {
434+ inside.push_str(block);
435+ inside.push('\n');
436+ } else {
437+ inside.push_str(&compact_css(block));
194438 }
195439 }
196− for selector in &pseudo_order {
197− if let Some(pairs) = pseudo_buckets.get(selector) {
198− emit_grouped_rules(&mut css, pairs, selector, inner_indent, dev);
440+
441+ let mut css = String::new();
442+ for (name, rules) in [
443+ ("hl-kind", kind),
444+ ("hl-inside", inside),
445+ ("htmlang", self.blocks(false, dev)),
446+ ] {
447+ if rules.is_empty() {
448+ continue;
449+ }
450+ if dev {
451+ css.push_str(&format!("@layer {} {{\n{}}}\n", name, rules));
452+ } else {
453+ css.push_str(&format!("@layer {}{{{}}}", name, rules));
199454 }
200455 }
456+ css
457+ }
201458
202− // Responsive rules grouped by breakpoint
203− for &(bp_name, bp_width) in BREAKPOINTS {
204− let mut bp_pairs: Vec<(&str, &str)> = Vec::new();
205− for e in &self.entries {
206− for (bp, rule_css) in &e.responsive {
207− if bp == bp_name && !rule_css.is_empty() {
208− bp_pairs.push((e.class_name.as_str(), rule_css.as_str()));
459+ /// The rules of every block of at-rules, in order: those for the
460+ /// elements inside (`inside`: rules under an element prefix, each in
461+ /// an `@scope` on its element's class), or the elements' own.
462+ fn blocks(&self, inside: bool, dev: bool) -> String {
463+ let mut css = String::new();
464+ let rules = || {
465+ self.entries.iter().flat_map(move |e| {
466+ e.rules
467+ .iter()
468+ .filter(move |(c, _)| c.inside().is_some() == inside)
469+ .map(move |(c, body)| (e, c, body))
470+ })
471+ };
472+ let mut blocks: Vec<&[usize]> = vec![&[]];
473+ let keyed = self.keyed.iter().filter(|_| !inside);
474+ let every = rules()
475+ .map(|(_, c, _)| c.at.as_slice())
476+ .chain(keyed.map(|(at, _, _)| at.as_slice()));
477+ for at in every {
478+ if !blocks.contains(&at) {
479+ blocks.push(at);
480+ }
481+ }
482+ blocks.sort_by_key(|at| at_order(at));
483+
484+ for at in blocks {
485+ let depth = at.len();
486+ // Readable output indents a rule inside `@layer` and inside
487+ // each at-rule but the first
488+ let indent = if dev {
489+ " ".repeat(depth.max(1))
490+ } else {
491+ String::new()
492+ };
493+ let mut inner = String::new();
494+ // Rules keyed on a parent's class come first: they have the
495+ // specificity of one class, like a class rule, so the child's
496+ // own rules in the block still win
497+ if !inside {
498+ let keyed: Vec<(&str, &str)> = self
499+ .keyed
500+ .iter()
501+ .filter(|(a, _, _)| a.as_slice() == at)
502+ .map(|(_, selector, body)| (selector.as_str(), body.as_str()))
503+ .collect();
504+ emit_selector_rules(&mut inner, &keyed, &indent, dev);
505+ }
506+ // The selector chains of this block, in order
507+ let mut chains: Vec<&[String]> = Vec::new();
508+ for (_, condition, _) in rules() {
509+ if condition.at == at && !chains.contains(&condition.selector.as_slice()) {
510+ chains.push(&condition.selector);
511+ }
512+ }
513+ if inside {
514+ chains.sort_by_cached_key(|chain| inside_order(chain));
515+ // One `@scope` for each root, its rules in the order of
516+ // the chains: rules for one element under two roots (`.a`
517+ // and `.a:hover`) tie on specificity and proximity, so the
518+ // later one wins
519+ let mut scopes: Vec<(String, Vec<(String, &str)>)> = Vec::new();
520+ for chain in chains {
521+ let Some(element) = chain
522+ .iter()
523+ .position(|p| crate::vocab::element_prefix(p).is_some())
524+ else {
525+ continue;
526+ };
527+ for (e, _, body) in
528+ rules().filter(|(_, c, _)| c.at == at && c.selector == chain)
529+ {
530+ let Some((root, target)) = scoped_selector(&e.class_name, chain, element)
531+ else {
532+ continue;
533+ };
534+ match scopes.iter_mut().find(|(r, _)| *r == root) {
535+ Some((_, targets)) => targets.push((target, body)),
536+ None => scopes.push((root, vec![(target, body)])),
537+ }
209538 }
210539 }
211− }
212− emit_media_block(
213− &mut css,
214− &format!("@media (min-width: {})", bp_width),
215− &format!("@media(min-width:{})", bp_width),
216− &bp_pairs,
217− "",
218− dev,
219− );
220− }
221−
222− // Dark mode rules
223− let dark_pairs: Vec<(&str, &str)> = self
224− .entries
225− .iter()
226− .filter(|e| !e.dark.is_empty())
227− .map(|e| (e.class_name.as_str(), e.dark.as_str()))
228− .collect();
229− emit_media_block(
230− &mut css,
231− "@media (prefers-color-scheme: dark)",
232− "@media(prefers-color-scheme:dark)",
233− &dark_pairs,
234− "",
235− dev,
236− );
237−
238− // Print rules
239− let print_pairs: Vec<(&str, &str)> = self
240− .entries
241− .iter()
242− .filter(|e| !e.print.is_empty())
243− .map(|e| (e.class_name.as_str(), e.print.as_str()))
244− .collect();
245− emit_media_block(
246− &mut css,
247− "@media print",
248− "@media print",
249− &print_pairs,
250− "",
251− dev,
252− );
253−
254− // Motion safe rules
255− let motion_safe_pairs: Vec<(&str, &str)> = self
256− .entries
257− .iter()
258− .filter(|e| !e.motion_safe.is_empty())
259− .map(|e| (e.class_name.as_str(), e.motion_safe.as_str()))
260− .collect();
261− emit_media_block(
262− &mut css,
263− "@media (prefers-reduced-motion: no-preference)",
264− "@media(prefers-reduced-motion:no-preference)",
265− &motion_safe_pairs,
266− "",
267− dev,
268− );
269−
270− // Motion reduce rules
271− let motion_reduce_pairs: Vec<(&str, &str)> = self
272− .entries
273− .iter()
274− .filter(|e| !e.motion_reduce.is_empty())
275− .map(|e| (e.class_name.as_str(), e.motion_reduce.as_str()))
276− .collect();
277− emit_media_block(
278− &mut css,
279− "@media (prefers-reduced-motion: reduce)",
280− "@media(prefers-reduced-motion:reduce)",
281− &motion_reduce_pairs,
282− "",
283− dev,
284− );
285−
286− // Landscape rules
287− let landscape_pairs: Vec<(&str, &str)> = self
288− .entries
289− .iter()
290− .filter(|e| !e.landscape.is_empty())
291− .map(|e| (e.class_name.as_str(), e.landscape.as_str()))
292− .collect();
293− emit_media_block(
294− &mut css,
295− "@media (orientation: landscape)",
296− "@media(orientation:landscape)",
297− &landscape_pairs,
298− "",
299− dev,
300− );
301−
302− // Portrait rules
303− let portrait_pairs: Vec<(&str, &str)> = self
304− .entries
305− .iter()
306− .filter(|e| !e.portrait.is_empty())
307− .map(|e| (e.class_name.as_str(), e.portrait.as_str()))
308− .collect();
309− emit_media_block(
310− &mut css,
311− "@media (orientation: portrait)",
312− "@media(orientation:portrait)",
313− &portrait_pairs,
314− "",
315− dev,
316− );
317−
318− // Container query rules grouped by breakpoint
319− for &(bp_name, bp_width) in BREAKPOINTS {
320− let mut cq_pairs: Vec<(&str, &str)> = Vec::new();
321− for e in &self.entries {
322− for (bp, rule_css) in &e.container {
323− if bp == bp_name && !rule_css.is_empty() {
324− cq_pairs.push((e.class_name.as_str(), rule_css.as_str()));
325− }
540+ let inner_indent = if dev {
541+ format!("{} ", indent)
542+ } else {
543+ String::new()
544+ };
545+ for (root, targets) in scopes {
546+ let targets: Vec<(&str, &str)> =
547+ targets.iter().map(|(t, b)| (t.as_str(), *b)).collect();
548+ inner.push_str(&indent);
549+ inner.push_str(&format!("@scope ({})", root));
550+ inner.push_str(if dev { " {\n" } else { "{" });
551+ emit_selector_rules(&mut inner, &targets, &inner_indent, dev);
552+ inner.push_str(&indent);
553+ inner.push_str(if dev { "}\n" } else { "}" });
326554 }
555+ } else {
556+ chains.sort_by_cached_key(|chain| selector_order(chain));
557+ for chain in chains {
558+ let pairs: Vec<(String, &str)> = rules()
559+ .filter(|(_, c, _)| c.at == at && c.selector == chain)
560+ .map(|(e, _, body)| (selector(&e.class_name, chain), body.as_str()))
561+ .collect();
562+ emit_grouped_rules(&mut inner, &pairs, &indent, dev);
563+ }
564+ }
565+ if inner.is_empty() {
566+ continue;
327567 }
328− emit_media_block(
329− &mut css,
330− &format!("@container (min-width: {})", bp_width),
331− &format!("@container(min-width:{})", bp_width),
332− &cq_pairs,
333− "",
334− dev,
335− );
568+ // Each at-rule wraps the next, outermost first
569+ for (level, &rank) in at.iter().enumerate().rev() {
570+ let pad = if dev {
571+ " ".repeat(level)
572+ } else {
573+ String::new()
574+ };
575+ inner = if dev {
576+ format!("{pad}{} {{\n{inner}{pad}}}\n", at_rule(rank, true))
577+ } else {
578+ format!("{}{{{inner}}}", at_rule(rank, false))
579+ };
580+ }
581+ css.push_str(&inner);
336582 }
337−
338− css.push_str(if dev { "}\n" } else { "}" });
339583 css
340584 }
341585}
342586
343−/// Emit CSS rules from `(class_name, body)` pairs, merging identical bodies
587+/// Emit CSS rules from `(selector, body)` pairs, merging identical bodies
344588/// into a single selector-list rule (e.g. `.a,.b{body}`). The first occurrence
345589/// of each distinct body determines ordering, so output stays deterministic
346−/// across runs. `selector_suffix` is appended to each class (e.g. `":hover"`,
347−/// or `""` for plain class rules). `indent` is prepended to each rule line.
348−fn emit_grouped_rules(
349− out: &mut String,
350− pairs: &[(&str, &str)],
351− selector_suffix: &str,
352− indent: &str,
353− dev: bool,
354−) {
590+/// across runs. `indent` is prepended to each rule line.
591+fn emit_grouped_rules(out: &mut String, pairs: &[(String, &str)], indent: &str, dev: bool) {
355592 if pairs.is_empty() {
356593 return;
357594 }
358595 // Group in first-occurrence order.
359596 let mut order: Vec<&str> = Vec::new();
360597 let mut groups: HashMap<&str, Vec<&str>> = HashMap::new();
361− for &(name, body) in pairs {
598+ for (selector, body) in pairs {
362599 if body.is_empty() {
363600 continue;
364601 }
365602 if !groups.contains_key(body) {
366603 order.push(body);
367604 }
368− groups.entry(body).or_default().push(name);
605+ groups.entry(body).or_default().push(selector);
369606 }
370607 let sp = if dev { " " } else { "" };
371608 let nl = if dev { "\n" } else { "" };
372609 for body in &order {
373− let names = &groups[body];
374610 out.push_str(indent);
375− for (i, n) in names.iter().enumerate() {
376− if i > 0 {
377− out.push(',');
378− }
379− out.push('.');
380− out.push_str(n);
381− out.push_str(selector_suffix);
382− }
611+ out.push_str(&groups[body].join(","));
383612 out.push_str(sp);
384613 out.push('{');
385614 out.push_str(body);
@@ -388,38 +617,44 @@ fn emit_grouped_rules(
388617 }
389618}
390619
391−/// Emit an `@media` / `@container` block containing grouped class rules.
392−/// Skips the block entirely if no non-empty bodies are present.
393−fn emit_media_block(
394− out: &mut String,
395− header_dev: &str,
396− header_min: &str,
397− pairs: &[(&str, &str)],
398− selector_suffix: &str,
399− dev: bool,
400−) {
401− if pairs.iter().all(|(_, body)| body.is_empty()) {
402− return;
403− }
404− let mut inner = String::new();
405− let inner_indent = if dev { " " } else { "" };
406− emit_grouped_rules(&mut inner, pairs, selector_suffix, inner_indent, dev);
407− if inner.is_empty() {
408− return;
409− }
410− if dev {
411− out.push_str(&format!("{} {{\n{}}}\n", header_dev, inner));
412− } else {
413− out.push_str(&format!("{}{{{}}}", header_min, inner));
620+/// Emit `(selector, body)` rules in their order, merging a run of rules
621+/// with the same body into one rule with a selector list (the order
622+/// matters: two rules may apply to one element).
623+fn emit_selector_rules(out: &mut String, rules: &[(&str, &str)], indent: &str, dev: bool) {
624+ let mut i = 0;
625+ while i < rules.len() {
626+ let body = rules[i].1;
627+ let run = rules[i..].iter().take_while(|(_, b)| *b == body).count();
628+ if !body.is_empty() {
629+ let selectors: Vec<&str> = rules[i..i + run].iter().map(|(s, _)| *s).collect();
630+ out.push_str(indent);
631+ out.push_str(&selectors.join(","));
632+ if dev {
633+ out.push(' ');
634+ }
635+ out.push('{');
636+ out.push_str(body);
637+ out.push('}');
638+ if dev {
639+ out.push('\n');
640+ }
641+ }
642+ i += run;
414643 }
415644}
416645
417646struct GenContext {
418647 dev: bool,
419648 depth: usize,
420− image_count: usize,
421649 has_interactive: bool,
422− has_defer: bool,
650+ /// Writing inside a text element, at any depth: htmlang's own `<div>`s
651+ /// are `<span>`s there, which text can hold.
652+ in_text: bool,
653+ /// How the element whose children are being written lays them out
654+ flow: Flow,
655+ /// Writing the children of a `@picture`, where `@source`'s leading
656+ /// argument is its `srcset`
657+ in_picture: bool,
423658}
424659
425660impl GenContext {
@@ -445,23 +680,26 @@ pub struct CodegenOptions {
445680 pub dev: bool,
446681 pub partial: bool,
447682 pub minify: bool,
448− pub compat: bool,
449683}
450684
451685/// Generate HTML from a parsed document using the given options.
452686pub fn generate_with(doc: &Document, opts: &CodegenOptions) -> String {
687+ generate_with_classes(doc, opts).0
688+}
689+
690+/// [`generate_with`], and the classes the document's styles were given,
691+/// for a check across files that no name stands for two styles.
692+pub fn generate_with_classes(doc: &Document, opts: &CodegenOptions) -> (String, Vec<Class>) {
693+ let mut classes = Vec::new();
453694 let mut html = if opts.partial {
454− generate_partial_inner(doc, opts.dev)
695+ generate_partial_inner(doc, opts.dev, &mut classes)
455696 } else {
456− generate_full_inner(doc, opts.dev)
697+ generate_full_inner(doc, opts.dev, &mut classes)
457698 };
458699 if opts.minify {
459700 html = minify_html(&html);
460701 }
461− if opts.compat {
462− html = add_vendor_prefixes(&html);
463− }
464− html
702+ (html, classes)
465703}
466704
467705pub fn generate(doc: &Document) -> String {
@@ -509,38 +747,6 @@ pub fn generate_minified(doc: &Document) -> String {
509747 )
510748}
511749
512−pub fn generate_compat(doc: &Document) -> String {
513− generate_with(
514− doc,
515− &CodegenOptions {
516− compat: true,
517− ..Default::default()
518− },
519− )
520−}
521−
522−pub fn generate_dev_compat(doc: &Document) -> String {
523− generate_with(
524− doc,
525− &CodegenOptions {
526− dev: true,
527− compat: true,
528− ..Default::default()
529− },
530− )
531−}
532−
533−pub fn generate_minified_compat(doc: &Document) -> String {
534− generate_with(
535− doc,
536− &CodegenOptions {
537− minify: true,
538− compat: true,
539− ..Default::default()
540− },
541− )
542−}
543−
544750fn minify_html(html: &str) -> String {
545751 let mut result = String::with_capacity(html.len());
546752 let mut in_pre = false;
@@ -619,514 +825,132 @@ fn minify_html(html: &str) -> String {
619825 result
620826}
621827
622−/// Add vendor prefixes to CSS within <style> tags for broader browser compatibility.
623−fn add_vendor_prefixes(html: &str) -> String {
624− // Find CSS within <style>...</style> and add vendor prefixes
625− let mut result = String::with_capacity(html.len() + 512);
626− let mut rest = html;
627− while let Some(start) = rest.find("<style>") {
628− let after_tag = start + 7;
629− result.push_str(&rest[..after_tag]);
630− rest = &rest[after_tag..];
631− if let Some(end) = rest.find("</style>") {
632− let css = &rest[..end];
633− result.push_str(&prefix_css(css));
634− result.push_str("</style>");
635− rest = &rest[end + 8..];
636− } else {
637− break;
638− }
639− }
640− result.push_str(rest);
641− result
642−}
643−
644−fn prefix_css(css: &str) -> String {
645− let mut out = String::with_capacity(css.len() + 256);
646− let mut i = 0;
647− let bytes = css.as_bytes();
648− while i < bytes.len() {
649− // Find property declarations
650− if let Some(pos) = css[i..].find('{') {
651− let brace = i + pos;
652− out.push_str(&css[i..=brace]);
653− i = brace + 1;
654− // Process declarations within this block
655− if let Some(close) = css[i..].find('}') {
656− let block = &css[i..i + close];
657− out.push_str(&prefix_declarations(block));
658− out.push('}');
659− i = i + close + 1;
660− }
661− } else {
662− out.push_str(&css[i..]);
663− break;
664− }
665− }
666− out
667−}
668−
669−fn prefix_declarations(block: &str) -> String {
670− let mut out = String::with_capacity(block.len() + 128);
671− for decl in block.split(';') {
672− let decl = decl.trim();
673− if decl.is_empty() {
674− continue;
675− }
676− if let Some((prop, val)) = decl.split_once(':') {
677− let prop = prop.trim();
678− let val = val.trim();
679− match prop {
680− "backdrop-filter" => {
681− out.push_str(&format!("-webkit-backdrop-filter:{};", val));
682− out.push_str(&format!("backdrop-filter:{};", val));
683− }
684− "user-select" => {
685− out.push_str(&format!("-webkit-user-select:{};", val));
686− out.push_str(&format!("-moz-user-select:{};", val));
687− out.push_str(&format!("user-select:{};", val));
688− }
689− "appearance" => {
690− out.push_str(&format!("-webkit-appearance:{};", val));
691− out.push_str(&format!("-moz-appearance:{};", val));
692− out.push_str(&format!("appearance:{};", val));
693− }
694− "background-clip" if val.contains("text") => {
695− out.push_str(&format!("-webkit-background-clip:{};", val));
696− out.push_str(&format!("background-clip:{};", val));
697− }
698− "hyphens" => {
699− out.push_str(&format!("-webkit-hyphens:{};", val));
700− out.push_str(&format!("-ms-hyphens:{};", val));
701− out.push_str(&format!("hyphens:{};", val));
702− }
703− "text-size-adjust" => {
704− out.push_str(&format!("-webkit-text-size-adjust:{};", val));
705− out.push_str(&format!("-ms-text-size-adjust:{};", val));
706− out.push_str(&format!("text-size-adjust:{};", val));
707− }
708− "mask-image" | "mask-size" | "mask-repeat" | "mask-position" => {
709− out.push_str(&format!("-webkit-{}:{};", prop, val));
710− out.push_str(&format!("{}:{};", prop, val));
711− }
712− _ => {
713− out.push_str(decl);
714− out.push(';');
715− }
716− }
717− } else {
718− out.push_str(decl);
719− out.push(';');
720− }
721− }
722− out
723−}
724−
725−fn generate_full_inner(doc: &Document, dev: bool) -> String {
828+fn generate_full_inner(doc: &Document, dev: bool, classes: &mut Vec<Class>) -> String {
829+ // Without `@page` the output is a fragment
830+ let Some(page) = &doc.page else {
831+ return generate_partial_inner(doc, dev, classes);
832+ };
726833 let mut styles = StyleCollector::new();
727834 let mut ctx = GenContext {
728835 dev,
729836 depth: 0,
730− image_count: 0,
731837 has_interactive: false,
732− has_defer: false,
838+ in_text: false,
839+ flow: Flow::default(),
840+ in_picture: false,
733841 };
734842
735− // Check if document has @main for skip-to-content link
736− let has_main = has_tag(&doc.nodes, "main");
843+ // The page is the root element: `<body>` is a column (the reset makes
844+ // it one, filling the viewport), `@page`'s styles are its class, and
845+ // the page's top-level elements are its children
846+ let root = Element {
847+ kind: ElementKind::El,
848+ attrs: page.styles.clone(),
849+ argument: None,
850+ children: Vec::new(),
851+ line_num: 0,
852+ function: None,
853+ };
854+ let mut own = Flow::of(&root);
855+ let top = Flow::default();
856+ let site = Site {
857+ kind: &root.kind,
858+ parent: &top,
859+ has_overlay_children: holds_overlays(&doc.nodes),
860+ inline: false,
861+ root: true,
862+ };
863+ let body_class = element_class(&root, &site, &mut styles);
864+ own.class = body_class.clone();
865+ ctx.flow = own;
737866
738867 let mut body = String::new();
868+ generate_children(
869+ &doc.nodes,
870+ Some(Layout::Column),
871+ &mut body,
872+ &mut styles,
873+ &mut ctx,
874+ );
739875
740− // Skip-to-content link for accessibility (only when @main exists)
741− if has_main {
742− if dev {
743− body.push_str("<a href=\"#hl-main\" class=\"hl-skip\">Skip to content</a>\n");
744− } else {
745− body.push_str("<a href=\"#hl-main\" class=\"hl-skip\">Skip to content</a>");
746− }
747− }
876+ let element_css = build_element_css(doc, &styles, dev);
877+ let nl = if dev { "\n" } else { "" };
748878
749− for node in &doc.nodes {
750− generate_node(node, None, &mut body, &mut styles, &mut ctx);
879+ let mut meta_html = String::new();
880+ // A `@meta viewport` of the page's own replaces the usual one
881+ if !doc.meta_tags.iter().any(|(name, _)| name == "viewport") {
882+ meta_html.push_str(&format!(
883+ "<meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">{}",
884+ nl
885+ ));
886+ }
887+ meta_html.push_str(&format!(
888+ "<title>{}</title>{}",
889+ html_escape(&page.title),
890+ nl
891+ ));
892+ for (name, content) in &doc.meta_tags {
893+ meta_html.push_str(&format!(
894+ "<meta name=\"{}\" content=\"{}\">{}",
895+ html_escape(name),
896+ html_escape(content),
897+ nl
898+ ));
899+ }
900+ for (property, content) in &doc.og_tags {
901+ meta_html.push_str(&format!(
902+ "<meta property=\"og:{}\" content=\"{}\">{}",
903+ html_escape(property),
904+ html_escape(content),
905+ nl
906+ ));
907+ }
908+ if let Some(path) = &page.favicon {
909+ meta_html.push_str(&format!(
910+ "<link rel=\"icon\" href=\"{}\">{}",
911+ html_escape(path),
912+ nl
913+ ));
914+ }
915+ for block in &doc.head_blocks {
916+ meta_html.push_str(block);
917+ meta_html.push_str(nl);
751918 }
752919
753− // Collect external domains for DNS prefetch
754− let dns_prefetch_html = collect_dns_prefetch(&body, dev);
755−
756− let element_css = build_element_css(doc, &styles, dev);
920+ // `@page`'s HTML attributes go on `<html>`
921+ let mut root_attrs = String::new();
922+ for attr in html_attrs(&page.html_attrs) {
923+ push_html_attr(&mut root_attrs, attr);
924+ }
925+ let mut body_attrs = String::new();
926+ emit_class_attr(&mut body_attrs, body_class.as_deref(), None);
757927
758− // Build meta tags string
759− let meta_html = if doc.meta_tags.is_empty() {
760− String::new()
761− } else {
762− let mut m = String::new();
763− for (name, content) in &doc.meta_tags {
764− if dev {
765− m.push_str(&format!(
766− "<meta name=\"{}\" content=\"{}\">\n",
767− html_escape(name),
768− html_escape(content)
769− ));
770− } else {
771− m.push_str(&format!(
772− "<meta name=\"{}\" content=\"{}\">",
773− html_escape(name),
774− html_escape(content)
775− ));
776− }
928+ // Focus-visible CSS for interactive elements (accessibility)
929+ let focus_visible_css = if ctx.has_interactive {
930+ let focusable = ":where(a,button,input,select,textarea):focus-visible";
931+ if dev {
932+ format!(
933+ "{}{} {{ outline: 2px solid currentColor; outline-offset: 2px; }}\n",
934+ OWN_ELEMENTS, focusable
935+ )
936+ } else {
937+ format!(
938+ "{}{}{{outline:2px solid currentColor;outline-offset:2px}}",
939+ OWN_ELEMENTS, focusable
940+ )
777941 }
778− m
779− };
780−
781− // Build OG meta tags
782− let og_html = if doc.og_tags.is_empty() {
783− String::new()
784942 } else {
785− let mut o = String::new();
786− for (property, content) in &doc.og_tags {
787− if dev {
788− o.push_str(&format!(
789− "<meta property=\"og:{}\" content=\"{}\">\n",
790− html_escape(property),
791− html_escape(content)
792− ));
793− } else {
794− o.push_str(&format!(
795− "<meta property=\"og:{}\" content=\"{}\">",
796− html_escape(property),
797− html_escape(content)
798− ));
799− }
800− }
801− o
802− };
803−
804− // Build head blocks string
805− let head_html = if doc.head_blocks.is_empty() {
806943 String::new()
807− } else {
808− let mut h = String::new();
809− for block in &doc.head_blocks {
810− h.push_str(block);
811− if dev {
812− h.push('\n');
813− }
814− }
815− h
816− };
817−
818− let lang_attr = match &doc.lang {
819− Some(lang) => format!(" lang=\"{}\"", html_escape(lang)),
820− None => String::new(),
821944 };
945+ let reset_css = reset_css(dev, true, &focus_visible_css);
946+ classes.extend(styles.classes());
822947
823− let favicon_html = match &doc.favicon {
824− Some(path) => {
825− // Try to read and inline the favicon
826− if let Ok(data) = std::fs::read(path) {
827− let mime = if path.ends_with(".ico") {
828− "image/x-icon"
829− } else if path.ends_with(".png") {
830− "image/png"
831− } else if path.ends_with(".svg") {
832− "image/svg+xml"
833− } else {
834− "image/x-icon"
835− };
836− let b64 = base64_encode(&data);
837− if dev {
838− format!(
839− "<link rel=\"icon\" href=\"data:{};base64,{}\">\n",
840− mime, b64
841− )
842− } else {
843− format!("<link rel=\"icon\" href=\"data:{};base64,{}\">", mime, b64)
844− }
845− } else {
846− // Fall back to href
847− if dev {
848− format!("<link rel=\"icon\" href=\"{}\">\n", html_escape(path))
849− } else {
850− format!("<link rel=\"icon\" href=\"{}\">", html_escape(path))
851− }
852− }
853− }
854− None => String::new(),
855− };
856−
857− // Canonical URL
858− let canonical_html = match &doc.canonical {
859− Some(url) => {
860− if dev {
861− format!("<link rel=\"canonical\" href=\"{}\">\n", html_escape(url))
862− } else {
863− format!("<link rel=\"canonical\" href=\"{}\">", html_escape(url))
864− }
865− }
866− None => String::new(),
867− };
868−
869− // Base URL
870− let base_html = match &doc.base_url {
871− Some(url) => {
872− if dev {
873− format!("<base href=\"{}\">\n", html_escape(url))
874− } else {
875− format!("<base href=\"{}\">", html_escape(url))
876− }
877− }
878− None => String::new(),
879− };
880−
881− // JSON-LD blocks
882− let json_ld_html: String = doc
883− .json_ld_blocks
884− .iter()
885− .map(|block| {
886− if dev {
887− format!(
888− "<script type=\"application/ld+json\">\n{}\n</script>\n",
889− block
890− )
891− } else {
892− format!("<script type=\"application/ld+json\">{}</script>", block)
893− }
894− })
895− .collect();
896−
897− // Manifest link
898− let manifest_html = if let Some(ref manifest) = doc.manifest {
899− let mut json = String::from("{");
900− json.push_str(&format!("\"name\":{},", json_str(&manifest.name)));
901− if let Some(ref short) = manifest.short_name {
902− json.push_str(&format!("\"short_name\":{},", json_str(short)));
903− }
904− json.push_str(&format!("\"start_url\":{},", json_str(&manifest.start_url)));
905− json.push_str(&format!("\"display\":{}", json_str(&manifest.display)));
906− if let Some(ref bg) = manifest.background_color {
907− json.push_str(&format!(",\"background_color\":{}", json_str(bg)));
908− }
909− if let Some(ref tc) = manifest.theme_color {
910− json.push_str(&format!(",\"theme_color\":{}", json_str(tc)));
911− }
912− if let Some(ref desc) = manifest.description {
913− json.push_str(&format!(",\"description\":{}", json_str(desc)));
914− }
915− if !manifest.icons.is_empty() {
916− json.push_str(",\"icons\":[");
917− for (i, (src, sizes)) in manifest.icons.iter().enumerate() {
918− if i > 0 {
919− json.push(',');
920− }
921− json.push_str(&format!(
922− "{{\"src\":{},\"sizes\":{},\"type\":\"image/png\"}}",
923− json_str(src),
924− json_str(sizes)
925− ));
926− }
927− json.push(']');
928− }
929− json.push('}');
930−
931− // Inline the manifest as a data URI
932− let encoded = base64_encode(json.as_bytes());
933− if dev {
934− format!(
935− "<link rel=\"manifest\" href=\"data:application/manifest+json;base64,{}\">\n",
936− encoded
937− )
938− } else {
939− format!(
940− "<link rel=\"manifest\" href=\"data:application/manifest+json;base64,{}\">",
941− encoded
942− )
943− }
944− } else {
945− String::new()
946− };
947−
948− // Preload hints (auto-detect fonts from @font-face)
949− let mut preload_html = String::new();
950− for (_, url) in &doc.font_faces {
951− if dev {
952− preload_html.push_str(&format!(
953− "<link rel=\"preload\" href=\"{}\" as=\"font\" type=\"font/woff2\" crossorigin>\n",
954− url
955− ));
956− } else {
957− preload_html.push_str(&format!(
958− "<link rel=\"preload\" href=\"{}\" as=\"font\" type=\"font/woff2\" crossorigin>",
959− url
960− ));
961− }
962− }
963− // Explicit preload hints from the document
964− for hint in &doc.preload_hints {
965− if dev {
966− preload_html.push_str(&format!(
967− "<link rel=\"preload\" href=\"{}\" as=\"{}\"{}>\n",
968− html_escape(&hint.href),
969− hint.as_type,
970− if hint.crossorigin { " crossorigin" } else { "" }
971− ));
972− } else {
973− preload_html.push_str(&format!(
974− "<link rel=\"preload\" href=\"{}\" as=\"{}\"{}>",
975− html_escape(&hint.href),
976− hint.as_type,
977− if hint.crossorigin { " crossorigin" } else { "" }
978− ));
979− }
980− }
981−
982− // Auto theme-color meta from @theme primary token
983− let theme_color_html = doc
984− .theme_tokens
985− .iter()
986− .find(|(name, _)| name == "primary" || name == "theme-color")
987− .map(|(_, value)| {
988− if dev {
989− format!(
990− "<meta name=\"theme-color\" content=\"{}\">\n",
991− html_escape(value)
992− )
993− } else {
994− format!(
995− "<meta name=\"theme-color\" content=\"{}\">",
996− html_escape(value)
997− )
998− }
999− })
1000− .unwrap_or_default();
1001−
1002− // Focus-visible CSS for interactive elements (accessibility)
1003− let focus_visible_css = if ctx.has_interactive {
1004− if dev {
1005− "a:focus-visible, button:focus-visible, input:focus-visible, select:focus-visible, textarea:focus-visible { outline: 2px solid currentColor; outline-offset: 2px; }\n"
1006− } else {
1007− "a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible{outline:2px solid currentColor;outline-offset:2px}"
1008− }
1009− } else {
1010− ""
1011− };
1012−
1013− // Skip-to-content CSS (visually hidden but accessible)
1014− let skip_link_css = if has_main {
1015− if dev {
1016− ".hl-skip { position: absolute; left: -9999px; top: auto; width: 1px; height: 1px; overflow: hidden; z-index: 9999; padding: 8px 16px; background: #000; color: #fff; text-decoration: none; font-size: 14px; }\n.hl-skip:focus { left: 8px; top: 8px; width: auto; height: auto; overflow: visible; }\n"
1017− } else {
1018− ".hl-skip{position:absolute;left:-9999px;top:auto;width:1px;height:1px;overflow:hidden;z-index:9999;padding:8px 16px;background:#000;color:#fff;text-decoration:none;font-size:14px}.hl-skip:focus{left:8px;top:8px;width:auto;height:auto;overflow:visible}"
1019− }
1020− } else {
1021− ""
1022− };
1023−
1024− // Noscript fallback: show deferred content if JS is disabled
1025− let noscript_html = if ctx.has_defer {
1026− if dev {
1027− "<noscript><style>.hl-defer-placeholder { display: none; }</style></noscript>\n"
1028− } else {
1029− "<noscript><style>.hl-defer-placeholder{display:none}</style></noscript>"
1030− }
1031− } else {
1032− ""
1033− };
1034−
1035− let reset_css = reset_css(dev, focus_visible_css, skip_link_css);
1036−
1037− match &doc.page_title {
1038− Some(title) => {
1039− if dev {
1040− format!(
1041− "\
1042−<!DOCTYPE html>
1043−<html{lang_attr}>
1044−<head>
1045−<meta charset=\"utf-8\">
1046−<meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">
1047−<title>{title}</title>
1048−{theme_color_html}{base_html}{canonical_html}{manifest_html}{preload_html}{dns_prefetch_html}{meta_html}{og_html}{favicon_html}{json_ld_html}{head_html}\
1049−<style>
1050−{reset_css}{element_css}\
1051−</style>
1052−{noscript_html}\
1053−</head>
1054−<body>
1055−{body}\
1056−</body>
1057−</html>
1058−",
1059− title = html_escape(title),
1060− lang_attr = lang_attr,
1061− theme_color_html = theme_color_html,
1062− base_html = base_html,
1063− canonical_html = canonical_html,
1064− manifest_html = manifest_html,
1065− preload_html = preload_html,
1066− dns_prefetch_html = dns_prefetch_html,
1067− meta_html = meta_html,
1068− favicon_html = favicon_html,
1069− json_ld_html = json_ld_html,
1070− head_html = head_html,
1071− og_html = og_html,
1072− reset_css = reset_css,
1073− noscript_html = noscript_html,
1074− element_css = element_css,
1075− body = body,
1076− )
1077− } else {
1078− format!(
1079− "<!DOCTYPE html><html{lang_attr}><head><meta charset=\"utf-8\"><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\"><title>{title}</title>{theme_color_html}{base_html}{canonical_html}{manifest_html}{preload_html}{dns_prefetch_html}{meta_html}{og_html}{favicon_html}{json_ld_html}{head_html}<style>{reset_css}{element_css}</style>{noscript_html}</head><body>{body}</body></html>",
1080− title = html_escape(title),
1081− lang_attr = lang_attr,
1082− theme_color_html = theme_color_html,
1083− base_html = base_html,
1084− canonical_html = canonical_html,
1085− manifest_html = manifest_html,
1086− preload_html = preload_html,
1087− dns_prefetch_html = dns_prefetch_html,
1088− meta_html = meta_html,
1089− og_html = og_html,
1090− favicon_html = favicon_html,
1091− json_ld_html = json_ld_html,
1092− head_html = head_html,
1093− reset_css = reset_css,
1094− noscript_html = noscript_html,
1095− element_css = element_css,
1096− body = body,
1097− )
1098− }
1099− }
1100− None => {
1101− if element_css.is_empty() {
1102− body
1103− } else if dev {
1104− format!("<style>\n{}</style>\n{}", element_css, body)
1105− } else {
1106− format!("<style>{}</style>{}", element_css, body)
1107− }
1108− }
1109− }
1110−}
1111−
1112−/// Encode `s` as a JSON string literal (with surrounding quotes).
1113−pub(crate) fn json_str(s: &str) -> String {
1114− let mut out = String::with_capacity(s.len() + 2);
1115− out.push('"');
1116− for c in s.chars() {
1117− match c {
1118− '"' => out.push_str("\\\""),
1119− '\\' => out.push_str("\\\\"),
1120− '\n' => out.push_str("\\n"),
1121− '\r' => out.push_str("\\r"),
1122− '\t' => out.push_str("\\t"),
1123− c if (c as u32) < 0x20 => out.push_str(&format!("\\u{:04x}", c as u32)),
1124− c => out.push(c),
1125− }
1126− }
1127− out.push('"');
1128− out
1129−}
948+ format!(
949+ "<!DOCTYPE html>{nl}<html{root_attrs}>{nl}<head>{nl}<meta charset=\"utf-8\">{nl}\
950+ {meta_html}<style>{nl}{reset_css}{element_css}</style>{nl}</head>{nl}\
951+ <body{body_attrs}>{nl}{body}</body>{nl}</html>{nl}",
952+ )
953+}
1130954
1131955/// Assemble every CSS block the document needs (font faces, custom
1132956/// properties, generated class rules, keyframes, and user CSS). Shared by
@@ -1134,63 +958,16 @@ pub(crate) fn json_str(s: &str) -> String {
1134958fn build_element_css(doc: &Document, styles: &StyleCollector, dev: bool) -> String {
1135959 let mut element_css = String::new();
1136960
1137− // @font-face rules, in declaration order
1138− for (name, url) in &doc.font_faces {
1139− let format_hint = if url.ends_with(".woff2") {
1140− " format('woff2')"
1141− } else if url.ends_with(".woff") {
1142− " format('woff')"
1143− } else if url.ends_with(".ttf") {
1144− " format('truetype')"
1145− } else if url.ends_with(".otf") {
1146− " format('opentype')"
1147− } else {
1148− ""
1149− };
1150− if dev {
1151− element_css.push_str(&format!(
1152− "@font-face {{\n font-family: '{}';\n src: url('{}'){};\n font-display: swap;\n}}\n",
1153− name, url, format_hint
1154− ));
1155− } else {
1156− element_css.push_str(&format!(
1157− "@font-face{{font-family:'{}';src:url('{}'){};font-display:swap}}",
1158− name, url, format_hint
1159− ));
1160− }
1161− }
1162−
1163− // Collect all CSS custom properties (explicit `@let --name` / `@theme`
1164− // tokens, plus any auto-extracted repeats) so they can be emitted in a
1165− // single `:root` block below.
961+ // Collect the CSS custom properties declared with `@let --name` so they
962+ // can be emitted in a single `:root` block below.
1166963 let mut root_vars: Vec<(String, String)> = Vec::new();
1167964 for (name, value) in &doc.css_vars {
1168965 root_vars.push((name.clone(), value.clone()));
1169966 }
1170− for (name, value) in &doc.theme_tokens {
1171− let css_name = format!("--{}", name);
1172− if !root_vars.iter().any(|(n, _)| *n == css_name) {
1173− root_vars.push((css_name, value.clone()));
1174− }
1175− }
1176967
1177− // Generated rules always go in `@layer htmlang`, so unlayered user CSS
968+ // Generated rules always go in htmlang's layers, so unlayered user CSS
1178969 // (`@style`, `@raw`) overrides them regardless of specificity.
1179− let styles_css = styles.to_css_formatted(dev);
1180− // Fold literal values declared via `@theme` / `@let --name` back into
1181− // `var(--name)` references so the generated CSS actually uses the
1182− // custom properties emitted in `:root`.
1183− let styles_css = substitute_css_vars(&styles_css, &root_vars);
1184− // Further compress the CSS by auto-extracting any remaining literal
1185− // values that appear often enough for `var(--hN)` references to come out
1186− // shorter overall. Disabled in dev mode to keep the CSS readable.
1187− let styles_css = if dev {
1188− styles_css
1189− } else {
1190− let (new_css, auto_vars) = auto_extract_repeats(&styles_css, &root_vars);
1191− root_vars.extend(auto_vars);
1192− new_css
1193− };
970+ let styles_css = styles.to_css_formatted(dev, &doc.scoped_css);
1194971
1195972 // Emit the :root block first so the cascade picks up the custom
1196973 // properties before the class rules consume them.
@@ -1215,72 +992,121 @@ fn build_element_css(doc: &Document, styles: &StyleCollector, dev: bool) -> Stri
1215992
1216993 element_css.push_str(&styles_css);
1217994
1218− // @keyframes
1219− for (name, kf_body) in &doc.keyframes {
1220− if dev {
1221− element_css.push_str(&format!("@keyframes {} {{\n{}\n}}\n", name, kf_body));
1222− } else {
1223− element_css.push_str(&format!("@keyframes {}{{{}}}", name, kf_body));
1224− }
1225− }
1226−
1227− // Auto-inject skeleton keyframe if skeleton attribute is used
1228− if element_css.contains("hl-skeleton") {
1229− if dev {
1230− element_css.push_str("@keyframes hl-skeleton {\n 0% { background-position: 200% 0; }\n 100% { background-position: -200% 0; }\n}\n");
1231− } else {
1232− element_css.push_str("@keyframes hl-skeleton{0%{background-position:200% 0}100%{background-position:-200% 0}}");
1233− }
1234− }
1235−
1236995 // @style blocks (custom CSS)
1237996 for block in &doc.custom_css {
1238997 if dev {
1239998 element_css.push_str(block);
1240999 element_css.push('\n');
12411000 } else {
1242− let minified: String = block.lines().map(|l| l.trim()).collect::<Vec<_>>().join("");
1243− element_css.push_str(&minified);
1001+ element_css.push_str(&compact_css(block));
12441002 }
12451003 }
12461004
12471005 element_css
12481006}
12491007
1008+/// An `@style` body on one line: each line trimmed, and the lines joined with
1009+/// a space, so a value that goes on over two lines (`margin: 0` then `auto;`)
1010+/// keeps its words apart.
1011+fn compact_css(block: &str) -> String {
1012+ block
1013+ .lines()
1014+ .map(str::trim)
1015+ .filter(|l| !l.is_empty())
1016+ .collect::<Vec<_>>()
1017+ .join(" ")
1018+}
1019+
1020+/// htmlang's own elements: those with a generated class, or the class of a
1021+/// function's scoped `@style`. The reset's rules for elements are kept to
1022+/// them, so `@raw` and `@markdown` content, and the page a fragment is put
1023+/// into, keep their own.
1024+const OWN_ELEMENTS: &str = ":where([class^=\"hl-\"],[class*=\" hl-\"])";
1025+
1026+/// htmlang's cascade layers, from the one that loses to the one that wins:
1027+/// the reset; the defaults of each element's kind (a heading's `margin:0`,
1028+/// a column's `display:flex`); the styles an element gets from an
1029+/// element prefix on an element around it (`@td:padding 8`) and from a
1030+/// function's scoped `@style`; and the element's own styles. So a
1031+/// scope's styles win over the defaults, and what an element says about
1032+/// itself wins over both. CSS outside any layer (`@style`, `@raw`) wins
1033+/// over all of them.
1034+const LAYERS: [&str; 4] = ["hl-reset", "hl-kind", "hl-inside", "htmlang"];
1035+
12501036/// Built-in reset rules, in a layer before `htmlang`: unlayered CSS beats
1251−/// every layer, so an unlayered `a{color:inherit}` would override
1252−/// `@link [color red]`.
1253−fn reset_css(dev: bool, focus_visible_css: &str, skip_link_css: &str) -> String {
1254− let base = if dev {
1255− "*, *::before, *::after { box-sizing: border-box; }\nbody { margin: 0; font-family: system-ui, -apple-system, sans-serif; }\nimg { display: block; }\na { text-decoration: none; color: inherit; }\n"
1037+/// every layer, so an unlayered rule here would override the generated
1038+/// ones. A page resets `box-sizing` everywhere and makes `<body>` a column
1039+/// that fills the window; a fragment, which goes into a page it doesn't
1040+/// own, touches only htmlang's own elements. In both, an element htmlang
1041+/// lays out stays hidden while it is `hidden`, a closed `<dialog>` or a
1042+/// popover that isn't showing: its generated `display` would otherwise
1043+/// beat the browser's `display: none`.
1044+fn reset_css(dev: bool, page: bool, focus_visible_css: &str) -> String {
1045+ let own = OWN_ELEMENTS;
1046+ let mut rules = Vec::new();
1047+ if page {
1048+ rules.push(if dev {
1049+ "*, *::before, *::after { box-sizing: border-box; }".to_string()
1050+ } else {
1051+ "*,*::before,*::after{box-sizing:border-box}".to_string()
1052+ });
1053+ rules.push(if dev {
1054+ "body { margin: 0; font-family: system-ui, -apple-system, sans-serif; display: flex; flex-direction: column; min-height: 100dvh; }".to_string()
1055+ } else {
1056+ "body{margin:0;font-family:system-ui,-apple-system,sans-serif;display:flex;flex-direction:column;min-height:100dvh}".to_string()
1057+ });
12561058 } else {
1257− "*,*::before,*::after{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,sans-serif}img{display:block}a{text-decoration:none;color:inherit}"
1258− };
1259− let rules = format!("{}{}{}", base, focus_visible_css, skip_link_css);
1059+ rules.push(if dev {
1060+ format!("{own}, {own}::before, {own}::after {{ box-sizing: border-box; }}")
1061+ } else {
1062+ format!("{own},{own}::before,{own}::after{{box-sizing:border-box}}")
1063+ });
1064+ }
1065+ let hidden = "[hidden]:not([hidden=\"until-found\"]),dialog:not([open]):not(:popover-open),\
1066+ [popover]:not(:popover-open):not(dialog[open])";
1067+ rules.push(if dev {
1068+ format!("{own}:where({hidden}) {{ display: none !important; }}")
1069+ } else {
1070+ format!("{own}:where({hidden}){{display:none!important}}")
1071+ });
1072+ let mut rules = rules.join(if dev { "\n" } else { "" });
1073+ if dev {
1074+ rules.push('\n');
1075+ }
1076+ rules.push_str(focus_visible_css);
12601077 if dev {
1261− format!("@layer hl-reset, htmlang;\n@layer hl-reset {{\n{}}}\n", rules)
1078+ format!(
1079+ "@layer {};\n@layer hl-reset {{\n{}}}\n",
1080+ LAYERS.join(", "),
1081+ rules
1082+ )
12621083 } else {
1263− format!("@layer hl-reset,htmlang;@layer hl-reset{{{}}}", rules)
1084+ format!("@layer {};@layer hl-reset{{{}}}", LAYERS.join(","), rules)
12641085 }
12651086}
12661087
12671088/// Generate an HTML fragment: body + optional <style>, no <html>/<head>/<body> wrapper.
1268−fn generate_partial_inner(doc: &Document, dev: bool) -> String {
1089+fn generate_partial_inner(doc: &Document, dev: bool, classes: &mut Vec<Class>) -> String {
12691090 let mut styles = StyleCollector::new();
12701091 let mut ctx = GenContext {
12711092 dev,
12721093 depth: 0,
1273− image_count: 0,
12741094 has_interactive: false,
1275− has_defer: false,
1095+ in_text: false,
1096+ flow: Flow::default(),
1097+ in_picture: false,
12761098 };
12771099 let mut body = String::new();
12781100
1279− for node in &doc.nodes {
1280− generate_node(node, None, &mut body, &mut styles, &mut ctx);
1281− }
1101+ generate_children(&doc.nodes, None, &mut body, &mut styles, &mut ctx);
12821102
1283− let element_css = build_element_css(doc, &styles, dev);
1103+ let mut element_css = build_element_css(doc, &styles, dev);
1104+ // htmlang's own elements get the reset's rules for elements (which
1105+ // also puts htmlang's layers in order)
1106+ if !styles.entries.is_empty() || !doc.scoped_css.is_empty() {
1107+ element_css.insert_str(0, &reset_css(dev, false, ""));
1108+ }
1109+ classes.extend(styles.classes());
12841110
12851111 if element_css.is_empty() {
12861112 body
@@ -1295,22 +1121,20 @@ fn generate_partial_inner(doc: &Document, dev: bool) -> String {
12951121// Node generation
12961122// ---------------------------------------------------------------------------
12971123
1124+/// Write `node`, which is inside an element with the layout `parent`
1125+/// (`None` at the top of the page).
12981126fn generate_node(
12991127 node: &Node,
1300− parent_kind: Option<&ElementKind>,
1128+ parent: Option<Layout>,
13011129 out: &mut String,
13021130 styles: &mut StyleCollector,
13031131 ctx: &mut GenContext,
13041132) {
13051133 match node {
1306− Node::Element(elem) => generate_element(elem, parent_kind, out, styles, ctx),
1134+ Node::Element(elem) => generate_element(elem, parent, out, styles, ctx),
13071135 Node::Text(segments) => {
1308− let needs_wrap = matches!(
1309− parent_kind,
1310− Some(ElementKind::Row | ElementKind::Column | ElementKind::El)
1311− ) || parent_kind
1312− .and_then(ElementKind::spec)
1313− .is_some_and(|spec| spec.wraps_text);
1136+ // In a row, column or grid each line of text is a child
1137+ let needs_wrap = parent.is_some_and(Layout::is_container);
13141138 if needs_wrap {
13151139 out.push_str(&ctx.indent());
13161140 out.push_str("<span>");
@@ -1329,69 +1153,156 @@ fn generate_node(
13291153 }
13301154}
13311155
1332−
1333−/// Emit the argument of an element whose argument is an HTML attribute
1334−/// (`@iframe URL` → `src="URL"`, `@form /submit` → `action="/submit"`).
1335−fn emit_argument_attr(out: &mut String, elem: &Element) {
1336− if let Some(TagSpec {
1337− arg: TagArg::Attr(attr),
1338− ..
1339− }) = elem.kind.spec()
1340− && let Some(value) = &elem.argument
1341− {
1342− out.push(' ');
1343− out.push_str(attr);
1344− out.push_str("=\"");
1345− out.push_str(&html_escape(value));
1346− out.push('"');
1156+/// What goes between two things written one after the other in an element
1157+/// with this layout (`None`: the top of the page): text flows, so its lines
1158+/// and children are joined with a space; in HTML's own layout, and at the
1159+/// top of the page, two lines of text are separated by a line break (a
1160+/// space, except where whitespace is kept, as in `@pre`).
1161+fn separator(layout: Option<Layout>, previous_is_text: bool, next: &Node) -> Option<char> {
1162+ match layout {
1163+ Some(Layout::Text) => Some(' '),
1164+ Some(Layout::Native) | None if previous_is_text && matches!(next, Node::Text(_)) => {
1165+ Some('\n')
1166+ }
1167+ _ => None,
13471168 }
13481169}
13491170
1350−fn emit_html_passthrough_attrs(out: &mut String, attrs: &[Attribute]) {
1351− for attr in attrs {
1352− let key = attr.key.as_str();
1353− if !crate::vocab::is_html_passthrough(key) {
1171+/// Write the children of an element (or of a `@fragment`, which has no
1172+/// element of its own) laid out as `layout` (`None`: the top of the page).
1173+/// The first line of an element's text is its first child.
1174+fn generate_children(
1175+ children: &[Node],
1176+ layout: Option<Layout>,
1177+ out: &mut String,
1178+ styles: &mut StyleCollector,
1179+ ctx: &mut GenContext,
1180+) {
1181+ generate_run(children, layout, &mut None, out, styles, ctx);
1182+}
1183+
1184+/// [`generate_children`], with `previous` saying whether what was written
1185+/// last was a line of text (`None`: nothing yet). A `@fragment`'s children
1186+/// are written as if they stood in its place, so its lines are separated
1187+/// from the lines around it like any other lines.
1188+fn generate_run(
1189+ children: &[Node],
1190+ layout: Option<Layout>,
1191+ previous: &mut Option<bool>,
1192+ out: &mut String,
1193+ styles: &mut StyleCollector,
1194+ ctx: &mut GenContext,
1195+) {
1196+ for child in children {
1197+ if let Node::Element(elem) = child
1198+ && elem.kind == ElementKind::Fragment
1199+ {
1200+ generate_run(&elem.children, layout, previous, out, styles, ctx);
13541201 continue;
13551202 }
1356− if crate::vocab::BOOLEAN_HTML_ATTRS.contains(&key) && attr.value.is_none() {
1357− out.push(' ');
1358− out.push_str(key);
1359− } else if let Some(val) = &attr.value {
1360− out.push(' ');
1361− out.push_str(key);
1362− out.push_str("=\"");
1363− out.push_str(&html_escape(strip_string_quotes(val)));
1364− out.push('"');
1203+ let start = out.len();
1204+ if let Some(previous_is_text) = *previous
1205+ && let Some(sep) = separator(layout, previous_is_text, child)
1206+ {
1207+ out.push(sep);
1208+ }
1209+ let body = out.len();
1210+ generate_node(child, layout, out, styles, ctx);
1211+ // A child that writes nothing (an empty `@fragment`) takes no
1212+ // separator either, so text never gets two spaces in a row
1213+ if out.len() == body {
1214+ out.truncate(start);
1215+ continue;
13651216 }
1217+ *previous = Some(matches!(child, Node::Text(_)));
13661218 }
13671219}
13681220
1369−/// If the value is wrapped in a single pair of matching quotes (e.g.
1370−/// `"Avatar"`), return the inner content. Quotes act as source-level
1371−/// delimiters in the `.hl` syntax and shouldn't leak into HTML attribute
1372−/// values. Multi-quoted values like `"h h" "s m"` are left unchanged —
1373−/// those are real string tokens (used e.g. by CSS `grid-template-areas`).
1374−fn strip_string_quotes(val: &str) -> &str {
1375− let bytes = val.as_bytes();
1376− if bytes.len() < 2 {
1377− return val;
1378− }
1379− let first = bytes[0];
1380− let last = bytes[bytes.len() - 1];
1381− if (first == b'"' && last == b'"') || (first == b'\'' && last == b'\'') {
1382− let inner = &val[1..val.len() - 1];
1383− if !inner.as_bytes().contains(&first) {
1384− return inner;
1221+/// Emit the element's leading argument as its attribute (`@iframe URL` →
1222+/// `src="URL"`, `@form /submit` → `action="/submit"`, `@link /a` →
1223+/// `href="/a"`), first, before the class. `@image [inline] photo.png` puts
1224+/// the file itself into the page.
1225+fn emit_argument_attr(out: &mut String, elem: &Element, in_picture: bool) {
1226+ let (Some(attr), Some(value)) = (elem.kind.leading_attribute(in_picture), &elem.argument)
1227+ else {
1228+ return;
1229+ };
1230+ // `@image [inline]`'s file is already a `data:` URI (see the parser)
1231+ let value = html_escape(value);
1232+ out.push(' ');
1233+ out.push_str(attr);
1234+ out.push_str("=\"");
1235+ out.push_str(&value);
1236+ out.push('"');
1237+}
1238+
1239+/// A file's bytes as a `data:` URI, its type from its extension.
1240+pub(crate) fn data_uri(path: &str, data: &[u8]) -> String {
1241+ let mime = match path
1242+ .rsplit('.')
1243+ .next()
1244+ .map(str::to_ascii_lowercase)
1245+ .as_deref()
1246+ {
1247+ Some("png") => "image/png",
1248+ Some("jpg" | "jpeg") => "image/jpeg",
1249+ Some("gif") => "image/gif",
1250+ Some("webp") => "image/webp",
1251+ Some("avif") => "image/avif",
1252+ Some("svg") => "image/svg+xml",
1253+ Some("ico") => "image/x-icon",
1254+ _ => "application/octet-stream",
1255+ };
1256+ format!("data:{};base64,{}", mime, base64_encode(data))
1257+}
1258+
1259+/// Emit HTML attributes: `key=value` ones (except `id` / `class`, which
1260+/// are emitted with the generated class) and flags like `required`.
1261+fn emit_html_attrs(out: &mut String, attrs: &[Attribute]) {
1262+ for attr in html_attrs(attrs) {
1263+ let key = attr.key.as_str();
1264+ if key != "id" && key != "class" {
1265+ push_html_attr(out, attr);
13851266 }
13861267 }
1387− val
1268+}
1269+
1270+/// The HTML attributes of `attrs`, `key=value` ones and flags, each name
1271+/// once: the later one wins, as a style does. (Of two attributes with one
1272+/// name, the browser keeps the first, so a bundle's attribute or a
1273+/// function's own would win over one written after it.)
1274+fn html_attrs(attrs: &[Attribute]) -> impl Iterator<Item = &Attribute> {
1275+ let is_html =
1276+ |a: &Attribute| a.html || (a.value.is_none() && crate::vocab::is_html_flag(&a.key));
1277+ attrs.iter().enumerate().filter_map(move |(i, attr)| {
1278+ let later = attrs[i + 1..]
1279+ .iter()
1280+ .any(|other| is_html(other) && other.key == attr.key);
1281+ (is_html(attr) && !later).then_some(attr)
1282+ })
1283+}
1284+
1285+/// ` key="value"`, or ` key` for a flag.
1286+fn push_html_attr(out: &mut String, attr: &Attribute) {
1287+ out.push(' ');
1288+ out.push_str(&attr.key);
1289+ if attr.html {
1290+ out.push_str("=\"");
1291+ // Quoted text has already lost its quotes (see parser.rs)
1292+ out.push_str(&html_escape(attr.value.as_deref().unwrap_or("")));
1293+ out.push('"');
1294+ }
13881295}
13891296
13901297// True if any direct child is `@in-front` or `@behind`. Such children render
13911298// as absolutely positioned overlays, so the parent automatically becomes a
13921299// positioning context (position:relative + isolation:isolate).
13931300fn has_overlay_children(elem: &Element) -> bool {
1394− elem.children.iter().any(|child| {
1301+ holds_overlays(&elem.children)
1302+}
1303+
1304+fn holds_overlays(children: &[Node]) -> bool {
1305+ children.iter().any(|child| {
13951306 matches!(
13961307 child,
13971308 Node::Element(e) if e.kind.is_tag("in-front") || e.kind.is_tag("behind")
@@ -1401,48 +1312,32 @@ fn has_overlay_children(elem: &Element) -> bool {
14011312
14021313fn generate_element(
14031314 elem: &Element,
1404− parent_kind: Option<&ElementKind>,
1315+ parent: Option<Layout>,
14051316 out: &mut String,
14061317 styles: &mut StyleCollector,
14071318 ctx: &mut GenContext,
14081319) {
14091320 // Self-closing elements
1410− if elem.kind == ElementKind::Image || elem.kind.spec().is_some_and(|spec| spec.void) {
1411− generate_self_closing(elem, parent_kind, out, styles, ctx);
1321+ if elem.kind.layout() == Layout::Void {
1322+ generate_self_closing(elem, parent, out, styles, ctx);
14121323 return;
14131324 }
1414− // @script renders as <script> with raw body content (no HTML escaping)
1415− if elem.kind == ElementKind::Script {
1325+ // A verbatim element (@script) writes its body as it is, with no HTML
1326+ // escaping; it isn't shown, so it has no class (its styles are an error)
1327+ if elem.kind.is_verbatim() {
1328+ let tag = elem.kind.spec().map_or("script", |spec| spec.html);
14161329 out.push_str(&ctx.indent());
1417− out.push_str("<script");
1418− // Pass through src, type, defer, async, etc.
1419− for attr in &elem.attrs {
1420− let key = attr.key.as_str();
1421− if matches!(
1422− key,
1423− "src"
1424− | "type"
1425− | "defer"
1426− | "async"
1427− | "crossorigin"
1428− | "integrity"
1429− | "nomodule"
1430− | "id"
1431− ) {
1432− if let Some(val) = &attr.value {
1433− out.push(' ');
1434− out.push_str(key);
1435− out.push_str("=\"");
1436− out.push_str(&html_escape(val));
1437− out.push('"');
1438− } else {
1439− out.push(' ');
1440− out.push_str(key);
1441− }
1330+ out.push('<');
1331+ out.push_str(tag);
1332+ emit_argument_attr(out, elem, false);
1333+ let (id, class) = extract_id_class(&elem.attrs);
1334+ for (key, value) in [("id", id), ("class", class)] {
1335+ if let Some(value) = value {
1336+ out.push_str(&format!(" {}=\"{}\"", key, html_escape(&value)));
14421337 }
14431338 }
1339+ emit_html_attrs(out, &elem.attrs);
14441340 out.push('>');
1445− // Children are raw JS code, not HTML
14461341 for child in &elem.children {
14471342 match child {
14481343 Node::Text(segments) => {
@@ -1456,46 +1351,10 @@ fn generate_element(
14561351 _ => {}
14571352 }
14581353 }
1459− out.push_str("</script>");
1460− out.push_str(ctx.nl());
1461− return;
1462− }
1463− // @breadcrumb generates semantic <nav aria-label="breadcrumb"><ol>...</ol></nav>
1464− if elem.kind == ElementKind::Breadcrumb {
1465− let gen_class = compute_class(&elem.attrs, &elem.kind, parent_kind, styles, false);
1466− let (id, user_class) = extract_id_class(&elem.attrs);
1467− out.push_str(&ctx.indent());
1468− out.push_str("<nav aria-label=\"breadcrumb\"");
1469− emit_class_attr(out, gen_class.as_deref(), user_class.as_deref());
1470− if let Some(id) = id {
1471− out.push_str(" id=\"");
1472− out.push_str(&html_escape(&id));
1473− out.push('"');
1474− }
1354+ out.push_str("</");
1355+ out.push_str(tag);
14751356 out.push('>');
14761357 out.push_str(ctx.nl());
1477− ctx.depth += 1;
1478− out.push_str(&ctx.indent());
1479− out.push_str("<ol>");
1480− out.push_str(ctx.nl());
1481− ctx.depth += 1;
1482− for child in &elem.children {
1483− out.push_str(&ctx.indent());
1484− out.push_str("<li>");
1485− let mut buf = String::new();
1486− generate_node(child, Some(&elem.kind), &mut buf, styles, ctx);
1487− out.push_str(buf.trim());
1488− out.push_str("</li>");
1489− out.push_str(ctx.nl());
1490− }
1491− ctx.depth -= 1;
1492− out.push_str(&ctx.indent());
1493− out.push_str("</ol>");
1494− out.push_str(ctx.nl());
1495− ctx.depth -= 1;
1496− out.push_str(&ctx.indent());
1497− out.push_str("</nav>");
1498− out.push_str(ctx.nl());
14991358 return;
15001359 }
15011360 if elem.kind == ElementKind::Children {
@@ -1505,26 +1364,26 @@ fn generate_element(
15051364 return;
15061365 }
15071366 if elem.kind == ElementKind::Fragment {
1508− // Render children without a wrapper element
1509− for child in &elem.children {
1510− generate_node(child, parent_kind, out, styles, ctx);
1511− }
1367+ // Render children without a wrapper element, as if they were
1368+ // written where the fragment is
1369+ generate_children(&elem.children, parent, out, styles, ctx);
15121370 return;
15131371 }
15141372
1373+ let mut own = Flow::of(elem);
15151374 let tag = match &elem.kind {
1516− ElementKind::Row | ElementKind::Column | ElementKind::El => "div",
1375+ ElementKind::Row | ElementKind::El => "div",
15171376 ElementKind::Text => "span",
15181377 ElementKind::Paragraph => "p",
15191378 ElementKind::Link => "a",
1520− ElementKind::Tag(spec)
1521− if spec.name == "list" && elem.attrs.iter().any(|a| a.key == "ordered") =>
1522− {
1523− "ol"
1524− }
15251379 ElementKind::Tag(spec) => spec.html,
15261380 _ => "",
15271381 };
1382+ // Inside text, htmlang's own `<div>` is a `<span>`, which text can
1383+ // hold (directly in text, a row, column or grid is also laid out
1384+ // inline: see `Site::inline`)
1385+ let in_text = ctx.in_text || parent == Some(Layout::Text);
1386+ let tag = if in_text && tag == "div" { "span" } else { tag };
15281387 let kind_label = elem.kind.name();
15291388
15301389 // Track interactive elements for focus-visible CSS
@@ -1535,14 +1394,8 @@ fn generate_element(
15351394 }
15361395
15371396 // Compute CSS for each state and get a class name
1538− let overlay_children = has_overlay_children(elem);
1539− let gen_class = compute_class(
1540− &elem.attrs,
1541− &elem.kind,
1542− parent_kind,
1543− styles,
1544− overlay_children,
1545− );
1397+ let gen_class = element_class(elem, &Site::new(elem, parent, &ctx.flow), styles);
1398+ own.class = gen_class.clone();
15461399 let (id, user_class) = extract_id_class(&elem.attrs);
15471400
15481401 if ctx.dev && elem.line_num > 0 {
@@ -1556,60 +1409,9 @@ fn generate_element(
15561409 out.push('<');
15571410 out.push_str(tag);
15581411
1559− // @main gets id="hl-main" for skip-to-content link (unless user set an id)
1560− if elem.kind.is_tag("main") && id.is_none() {
1561− out.push_str(" id=\"hl-main\"");
1562− }
1563−
1564− if elem.kind == ElementKind::Link
1565− && let Some(url) = &elem.argument
1566− {
1567− out.push_str(" href=\"");
1568− out.push_str(&html_escape(url));
1569− out.push('"');
1570− // Auto rel="noopener noreferrer" and target="_blank" for external links
1571− let is_external = url.starts_with("http://") || url.starts_with("https://");
1572− if is_external {
1573− let has_rel = elem.attrs.iter().any(|a| a.key == "rel");
1574− let has_target = elem.attrs.iter().any(|a| a.key == "target");
1575− if !has_rel {
1576− out.push_str(" rel=\"noopener noreferrer\"");
1577− }
1578− if !has_target {
1579− out.push_str(" target=\"_blank\"");
1580− }
1581− }
1582− }
1583−
1584− emit_argument_attr(out, elem);
1585−
1586− // Tooltip title
1587− if elem.kind.is_tag("tooltip")
1588− && let Some(text) = &elem.argument
1589− {
1590− out.push_str(" title=\"");
1591− out.push_str(&html_escape(text));
1592− out.push('"');
1593− }
1412+ emit_argument_attr(out, elem, ctx.in_picture);
15941413
1595− // Critical CSS: inline styles directly instead of using a class
1596− let is_critical = elem.attrs.iter().any(|a| a.key == "critical");
1597− if is_critical {
1598− let inline_css = attrs_to_css(&elem.attrs, "", &elem.kind, parent_kind, overlay_children);
1599− if !inline_css.is_empty() {
1600− out.push_str(" style=\"");
1601− out.push_str(&html_escape(&inline_css));
1602− out.push('"');
1603− }
1604− // Still use class for non-base styles (pseudo, responsive, etc.)
1605− if gen_class.as_deref().is_some_and(|c| !c.is_empty()) {
1606− emit_class_attr(out, gen_class.as_deref(), user_class.as_deref());
1607− } else if let Some(ref uc) = user_class {
1608− emit_class_attr(out, None, Some(uc));
1609− }
1610− } else {
1611− emit_class_attr(out, gen_class.as_deref(), user_class.as_deref());
1612− }
1414+ emit_class_attr(out, gen_class.as_deref(), user_class.as_deref());
16131415
16141416 if let Some(id) = id {
16151417 out.push_str(" id=\"");
@@ -1617,7 +1419,7 @@ fn generate_element(
16171419 out.push('"');
16181420 }
16191421
1620− emit_html_passthrough_attrs(out, &elem.attrs);
1422+ emit_html_attrs(out, &elem.attrs);
16211423
16221424 // Source map attributes in dev mode
16231425 if ctx.dev && elem.line_num > 0 {
@@ -1628,28 +1430,27 @@ fn generate_element(
16281430 }
16291431
16301432 out.push('>');
1433+ // In `<pre>` and `<textarea>` every space and line break shows, so
1434+ // readable (dev) output adds none there: a code sample's lines stay
1435+ // exactly as written
1436+ let outer_dev = ctx.dev;
1437+ ctx.dev &= !matches!(tag, "pre" | "textarea");
16311438 out.push_str(ctx.nl());
16321439
1633− // Inline text argument
1634− if renders_argument_as_text(&elem.kind)
1635− && let Some(text) = &elem.argument
1636− {
1637− out.push_str(&html_escape(text));
1638− }
1639−
1640− // Children
1440+ let layout = elem.kind.layout();
16411441 ctx.depth += 1;
1642− let is_paragraph = elem.kind == ElementKind::Paragraph
1643− || elem.kind.spec().is_some_and(|spec| spec.inline);
1644− for (i, child) in elem.children.iter().enumerate() {
1645− generate_node(child, Some(&elem.kind), out, styles, ctx);
1646− if is_paragraph && i < elem.children.len() - 1 {
1647− out.push(' ');
1648− }
1649− }
1442+ let outer_in_text = ctx.in_text;
1443+ ctx.in_text = in_text || layout == Layout::Text;
1444+ let outer_flow = std::mem::replace(&mut ctx.flow, own);
1445+ let outer_picture = std::mem::replace(&mut ctx.in_picture, elem.kind.is_tag("picture"));
1446+ generate_children(&elem.children, Some(layout), out, styles, ctx);
1447+ ctx.in_picture = outer_picture;
1448+ ctx.flow = outer_flow;
1449+ ctx.in_text = outer_in_text;
16501450 ctx.depth -= 1;
16511451
16521452 out.push_str(&ctx.indent());
1453+ ctx.dev = outer_dev;
16531454 out.push_str("</");
16541455 out.push_str(tag);
16551456 out.push('>');
@@ -1658,12 +1459,12 @@ fn generate_element(
16581459
16591460fn generate_self_closing(
16601461 elem: &Element,
1661− parent_kind: Option<&ElementKind>,
1462+ parent: Option<Layout>,
16621463 out: &mut String,
16631464 styles: &mut StyleCollector,
16641465 ctx: &mut GenContext,
16651466) {
1666− let gen_class = compute_class(&elem.attrs, &elem.kind, parent_kind, styles, false);
1467+ let gen_class = element_class(elem, &Site::new(elem, parent, &ctx.flow), styles);
16671468 let (id, user_class) = extract_id_class(&elem.attrs);
16681469
16691470 let (tag, kind_label) = match &elem.kind {
@@ -1682,44 +1483,7 @@ fn generate_self_closing(
16821483 out.push_str(&ctx.indent());
16831484 out.push('<');
16841485 out.push_str(tag);
1685− emit_argument_attr(out, elem);
1686−
1687− // Image src (with optional non-SVG base64 inlining)
1688− if elem.kind == ElementKind::Image {
1689− let src = elem.argument.as_deref().unwrap_or("");
1690− let is_inline = elem.attrs.iter().any(|a| a.key == "inline");
1691− if is_inline && !src.is_empty() && !src.ends_with(".svg") {
1692− let mime = if src.ends_with(".png") {
1693− "image/png"
1694− } else if src.ends_with(".jpg") || src.ends_with(".jpeg") {
1695− "image/jpeg"
1696− } else if src.ends_with(".gif") {
1697− "image/gif"
1698− } else if src.ends_with(".webp") {
1699− "image/webp"
1700− } else if src.ends_with(".avif") {
1701− "image/avif"
1702− } else {
1703− "application/octet-stream"
1704− };
1705− if let Ok(data) = std::fs::read(src) {
1706− let b64 = base64_encode(&data);
1707− out.push_str(" src=\"data:");
1708− out.push_str(mime);
1709− out.push_str(";base64,");
1710− out.push_str(&b64);
1711− out.push('"');
1712− } else {
1713− out.push_str(" src=\"");
1714− out.push_str(&html_escape(src));
1715− out.push('"');
1716− }
1717− } else {
1718− out.push_str(" src=\"");
1719− out.push_str(&html_escape(src));
1720− out.push('"');
1721− }
1722− }
1486+ emit_argument_attr(out, elem, ctx.in_picture);
17231487
17241488 emit_class_attr(out, gen_class.as_deref(), user_class.as_deref());
17251489
@@ -1729,7 +1493,7 @@ fn generate_self_closing(
17291493 out.push('"');
17301494 }
17311495
1732− emit_html_passthrough_attrs(out, &elem.attrs);
1496+ emit_html_attrs(out, &elem.attrs);
17331497
17341498 // Source map attributes in dev mode (self-closing)
17351499 if ctx.dev && elem.line_num > 0 {
@@ -1739,93 +1503,6 @@ fn generate_self_closing(
17391503 ));
17401504 }
17411505
1742− // Image optimization: auto-add loading="lazy" and decoding="async"
1743− if elem.kind == ElementKind::Image {
1744− // SVG inlining: @image [inline] logo.svg
1745− if elem.attrs.iter().any(|a| a.key == "inline")
1746− && let Some(src) = &elem.argument
1747− && src.ends_with(".svg")
1748− && let Ok(svg_content) = std::fs::read_to_string(src)
1749− {
1750− // Close the tag we opened, then emit inline SVG instead
1751− out.truncate(out.rfind('<').unwrap_or(0));
1752− out.push_str(&ctx.indent());
1753− out.push_str(svg_content.trim());
1754− out.push_str(ctx.nl());
1755− return;
1756− }
1757− // Responsive srcset: @image photo.jpg [responsive 400 800 1200]
1758− let responsive_attr = elem.attrs.iter().find(|a| a.key == "responsive");
1759− if let Some(resp) = responsive_attr
1760− && let Some(ref sizes_str) = resp.value
1761− {
1762− let widths: Vec<&str> = sizes_str.split_whitespace().collect();
1763− if !widths.is_empty() {
1764− let src = elem.argument.as_deref().unwrap_or("");
1765− if !src.is_empty() {
1766− // Generate srcset with width descriptors
1767− // Convention: file-{width}.ext (e.g., photo-400.jpg)
1768− let dot_pos = src.rfind('.').unwrap_or(src.len());
1769− let base = &src[..dot_pos];
1770− let ext = &src[dot_pos..];
1771− let mut srcset_parts = Vec::new();
1772− for w in &widths {
1773− srcset_parts.push(format!("{}-{}{} {}w", base, w, ext, w));
1774− }
1775− out.push_str(" srcset=\"");
1776− out.push_str(&srcset_parts.join(", "));
1777− out.push('"');
1778− // Generate sizes attribute
1779− let max_width = widths.last().unwrap_or(&"100vw");
1780− out.push_str(&format!(
1781− " sizes=\"(max-width: {}px) 100vw, {}px\"",
1782− max_width, max_width
1783− ));
1784− }
1785− }
1786− }
1787−
1788− // Auto image dimensions: read local image file to inject width/height + aspect-ratio
1789− let has_width = elem.attrs.iter().any(|a| a.key == "width");
1790− let has_height = elem.attrs.iter().any(|a| a.key == "height");
1791− if (!has_width || !has_height)
1792− && let Some(ref src) = elem.argument
1793− && !src.starts_with("http://")
1794− && !src.starts_with("https://")
1795− && !src.starts_with("data:")
1796− && let Some((w, h)) = read_image_dimensions(src)
1797− {
1798− // Intrinsic size attributes only when neither dimension is set in
1799− // CSS; with one CSS dimension, a leftover intrinsic attribute for
1800− // the other would distort the image (200 wide but 1000 tall).
1801− if !has_width && !has_height {
1802− out.push_str(&format!(" width=\"{}\" height=\"{}\"", w, h));
1803− }
1804− // Auto aspect-ratio to prevent CLS
1805− if !elem.attrs.iter().any(|a| a.key == "aspect-ratio") {
1806− out.push_str(&format!(" style=\"aspect-ratio:{}/{}\"", w, h));
1807− }
1808− }
1809−
1810− // Smart image loading: first 3 images get fetchpriority="high" (above the fold),
1811− // subsequent images get loading="lazy" + decoding="async"
1812− ctx.image_count += 1;
1813− if ctx.image_count <= 3 {
1814− // Above-the-fold: eager loading with high priority
1815− if !elem.attrs.iter().any(|a| a.key == "fetchpriority") {
1816− out.push_str(" fetchpriority=\"high\"");
1817− }
1818− } else {
1819− // Below-the-fold: lazy loading
1820− if !elem.attrs.iter().any(|a| a.key == "loading") {
1821− out.push_str(" loading=\"lazy\"");
1822− }
1823− if !elem.attrs.iter().any(|a| a.key == "decoding") {
1824− out.push_str(" decoding=\"async\"");
1825− }
1826− }
1827− }
1828−
18291506 out.push('>');
18301507 out.push_str(ctx.nl());
18311508}
@@ -1841,7 +1518,10 @@ fn generate_text_segments(
18411518 TextSegment::Plain(text) => out.push_str(&html_escape(text)),
18421519 TextSegment::Inline(elem) => {
18431520 let mut buf = String::new();
1844− generate_element(elem, None, &mut buf, styles, ctx);
1521+ // An element inside a line of text is in text
1522+ let outer_flow = std::mem::take(&mut ctx.flow);
1523+ generate_element(elem, Some(Layout::Text), &mut buf, styles, ctx);
1524+ ctx.flow = outer_flow;
18451525 out.push_str(buf.trim_end());
18461526 }
18471527 }
@@ -1854,143 +1534,97 @@ fn generate_text_segments(
18541534
18551535fn compute_class(
18561536 attrs: &[Attribute],
1857− kind: &ElementKind,
1858− parent_kind: Option<&ElementKind>,
1537+ site: &Site,
18591538 styles: &mut StyleCollector,
1860− has_overlay_children: bool,
1539+ distinct: String,
18611540) -> Option<String> {
1862− let base = attrs_to_css(attrs, "", kind, parent_kind, has_overlay_children);
1863−
1864− // Collect pseudo-state overrides
1865− let mut pseudo = Vec::new();
1866− for &(prefix, selector) in PSEUDO_PREFIXES {
1867− let css = attrs_to_css(attrs, prefix, kind, parent_kind, has_overlay_children);
1868− if !css.is_empty() {
1869− pseudo.push((selector.to_string(), css));
1870− }
1871− }
1872−
1873− // Auto-add ::-webkit-scrollbar pseudo for no-scrollbar attribute
1874− if attrs.iter().any(|a| a.key == "no-scrollbar") {
1875− pseudo.push((
1876− "::-webkit-scrollbar".to_string(),
1877− "display:none;".to_string(),
1878− ));
1879− }
1880−
1881− // Collect nth:EXPR: dynamic pseudo selectors
1882− let mut nth_prefixes: Vec<String> = Vec::new();
1883− for attr in attrs {
1884− if attr.key.starts_with("nth:") {
1885− let rest = &attr.key[4..];
1886− if let Some(colon_pos) = rest.find(':') {
1887− let prefix = format!("nth:{}:", &rest[..colon_pos]);
1888− if !nth_prefixes.contains(&prefix) {
1889− nth_prefixes.push(prefix);
1890− }
1891− }
1892− }
1893− }
1894− for prefix in &nth_prefixes {
1895− let expr = &prefix[4..prefix.len() - 1];
1896− let selector = format!(":nth-child({})", expr);
1897− let css = attrs_to_css(attrs, prefix, kind, parent_kind, has_overlay_children);
1898− if !css.is_empty() {
1899− pseudo.push((selector, css));
1541+ // Every condition an attribute is under, and none
1542+ let mut conditions = vec![Condition::default()];
1543+ for attr in attrs.iter().filter(|a| !a.html) {
1544+ let (condition, _) = Condition::of(&attr.key);
1545+ if !conditions.contains(&condition) {
1546+ conditions.push(condition);
19001547 }
19011548 }
1549+ // Dedupe: if a property is declared twice within a single rule, keep only
1550+ // the last occurrence.
1551+ let rules: Vec<(Condition, String)> = conditions
1552+ .into_iter()
1553+ .map(|condition| {
1554+ let css = dedupe_declarations(&attrs_to_css(attrs, &condition, site));
1555+ (condition, css)
1556+ })
1557+ .collect();
1558+ // The kind's defaults, less what the element sets itself (a user
1559+ // `[list-style disc]` wins over the default `list-style:none` anyway,
1560+ // so there is no need to ship both)
1561+ let own = rules
1562+ .iter()
1563+ .find(|(condition, _)| *condition == Condition::default())
1564+ .map_or("", |(_, css)| css.as_str());
1565+ let own: Vec<&str> = declarations(own).map(|(name, _)| name).collect();
1566+ let defaults: String = declarations(&dedupe_declarations(&default_css(site)))
1567+ .filter(|(name, _)| !own.contains(name))
1568+ .map(|(_, declaration)| declaration)
1569+ .collect();
1570+ styles.get_class(defaults, rules, distinct)
1571+}
19021572
1903− // Collect has(...): dynamic pseudo selectors
1904− let mut has_prefixes: Vec<String> = Vec::new();
1905− for attr in attrs {
1906− if attr.key.starts_with("has(")
1907− && let Some(close) = attr.key.find("):")
1908− {
1909− let prefix = format!("{}:", &attr.key[..close + 1]);
1910− if !has_prefixes.contains(&prefix) {
1911− has_prefixes.push(prefix);
1912− }
1913− }
1573+/// The defaults of an element's kind where it is: an overlay's positioning
1574+/// context, its layout, and its kind's own CSS (a heading's `margin:0`).
1575+fn default_css(site: &Site) -> String {
1576+ let mut css = String::new();
1577+ // Elements with @in-front / @behind children become positioning
1578+ // contexts
1579+ if site.has_overlay_children {
1580+ css.push_str("position:relative;isolation:isolate;");
19141581 }
1915− for prefix in &has_prefixes {
1916− let inner = &prefix[4..prefix.len() - 2]; // extract selector from has(selector):
1917− let selector = format!(":has({})", inner);
1918− let css = attrs_to_css(attrs, prefix, kind, parent_kind, has_overlay_children);
1919− if !css.is_empty() {
1920− pseudo.push((selector, css));
1921− }
1582+ if !site.root {
1583+ css.push_str(layout_css(site.kind.layout(), site.inline));
19221584 }
1585+ css.push_str(site.kind.css());
1586+ css
1587+}
19231588
1924− // Collect responsive overrides
1925− let mut responsive = Vec::new();
1926− for &(bp_name, _) in BREAKPOINTS {
1927− let prefix = format!("{}:", bp_name);
1928− let css = attrs_to_css(attrs, &prefix, kind, parent_kind, has_overlay_children);
1929− if !css.is_empty() {
1930− responsive.push((bp_name.to_string(), css));
1589+/// The declarations of a rule body, as (property, `property:value;`), for
1590+/// bodies htmlang wrote: every declaration ends in `;`, and a `;` inside
1591+/// quotes or parentheses doesn't end one.
1592+fn declarations(css: &str) -> impl Iterator<Item = (&str, &str)> {
1593+ let mut rest = css;
1594+ std::iter::from_fn(move || {
1595+ if rest.is_empty() {
1596+ return None;
19311597 }
1932− }
1933−
1934− // Collect container query overrides
1935− let mut container = Vec::new();
1936− for &(bp_name, _) in BREAKPOINTS {
1937− let prefix = format!("cq-{}:", bp_name);
1938− let css = attrs_to_css(attrs, &prefix, kind, parent_kind, has_overlay_children);
1939− if !css.is_empty() {
1940− container.push((bp_name.to_string(), css));
1598+ let (mut depth, mut quote, mut escaped) = (0i32, None, false);
1599+ let mut end = rest.len();
1600+ for (i, c) in rest.char_indices() {
1601+ match c {
1602+ _ if escaped => escaped = false,
1603+ '\\' => escaped = true,
1604+ c if Some(c) == quote => quote = None,
1605+ _ if quote.is_some() => {}
1606+ '"' | '\'' => quote = Some(c),
1607+ '(' => depth += 1,
1608+ ')' => depth -= 1,
1609+ ';' if depth == 0 => {
1610+ end = i + 1;
1611+ break;
1612+ }
1613+ _ => {}
1614+ }
19411615 }
1942− }
1943−
1944− let dark = attrs_to_css(attrs, "dark:", kind, parent_kind, has_overlay_children);
1945− let print = attrs_to_css(attrs, "print:", kind, parent_kind, has_overlay_children);
1946− let motion_safe = attrs_to_css(attrs, "motion-safe:", kind, parent_kind, has_overlay_children);
1947− let motion_reduce =
1948− attrs_to_css(attrs, "motion-reduce:", kind, parent_kind, has_overlay_children);
1949− let landscape = attrs_to_css(attrs, "landscape:", kind, parent_kind, has_overlay_children);
1950− let portrait = attrs_to_css(attrs, "portrait:", kind, parent_kind, has_overlay_children);
1951−
1952− // Dedupe: if a property is declared twice within a single rule, keep only
1953− // the last occurrence (element-kind defaults are written before
1954− // user attributes, so a user [list-style disc] correctly overrides the
1955− // default list-style:none, and we don't need to ship both).
1956− let base = dedupe_declarations(&base);
1957− let pseudo: Vec<(String, String)> = pseudo
1958− .into_iter()
1959− .map(|(sel, css)| (sel, dedupe_declarations(&css)))
1960− .collect();
1961− let responsive: Vec<(String, String)> = responsive
1962− .into_iter()
1963− .map(|(bp, css)| (bp, dedupe_declarations(&css)))
1964− .collect();
1965− let dark = dedupe_declarations(&dark);
1966− let print = dedupe_declarations(&print);
1967− let motion_safe = dedupe_declarations(&motion_safe);
1968− let motion_reduce = dedupe_declarations(&motion_reduce);
1969− let landscape = dedupe_declarations(&landscape);
1970− let portrait = dedupe_declarations(&portrait);
1971− let container: Vec<(String, String)> = container
1972− .into_iter()
1973− .map(|(bp, css)| (bp, dedupe_declarations(&css)))
1974− .collect();
1975−
1976− styles.get_class(
1977− base,
1978− pseudo,
1979− responsive,
1980− dark,
1981− print,
1982− motion_safe,
1983− motion_reduce,
1984− landscape,
1985− portrait,
1986− container,
1987− )
1616+ let (declaration, after) = rest.split_at(end);
1617+ rest = after;
1618+ let name = declaration.split(':').next().unwrap_or("").trim();
1619+ Some((name, declaration))
1620+ })
19881621}
19891622
19901623/// Dedupe CSS declarations within a single rule body: for any property
19911624/// declared more than once, keep only the last occurrence. Unparseable
1992−/// segments (no `:`) are preserved as-is. Semicolons inside parentheses are
1993−/// treated as part of a value, not as declaration separators.
1625+/// segments (no `:`) are preserved as-is. Semicolons inside parentheses or
1626+/// quoted strings are treated as part of a value, not as declaration
1627+/// separators.
19941628fn dedupe_declarations(css: &str) -> String {
19951629 if css.is_empty() {
19961630 return String::new();
@@ -2005,8 +1639,26 @@ fn dedupe_declarations(css: &str) -> String {
20051639 let mut decls: Vec<(Option<String>, String)> = Vec::new();
20061640 let mut current = String::new();
20071641 let mut depth: i32 = 0;
1642+ // A quoted string's `;` (`content "a;b"`) is text; a backslash escapes
1643+ // the character after it
1644+ let mut quote: Option<char> = None;
1645+ let mut escaped = false;
20081646 for ch in css.chars() {
2009− if ch == '(' {
1647+ if escaped {
1648+ escaped = false;
1649+ current.push(ch);
1650+ } else if ch == '\\' {
1651+ escaped = true;
1652+ current.push(ch);
1653+ } else if let Some(q) = quote {
1654+ if ch == q {
1655+ quote = None;
1656+ }
1657+ current.push(ch);
1658+ } else if ch == '"' || ch == '\'' {
1659+ quote = Some(ch);
1660+ current.push(ch);
1661+ } else if ch == '(' {
20101662 depth += 1;
20111663 current.push(ch);
20121664 } else if ch == ')' {
@@ -2088,642 +1740,553 @@ fn emit_class_attr(out: &mut String, gen_class: Option<&str>, user_class: Option
20881740// Attribute → CSS mapping
20891741// ---------------------------------------------------------------------------
20901742
2091−/// (htmlang prefix, CSS selector suffix)
2092−const PSEUDO_PREFIXES: &[(&str, &str)] = &[
2093− ("hover:", ":hover"),
2094− ("active:", ":active"),
2095− ("focus:", ":focus"),
2096− ("focus-visible:", ":focus-visible"),
2097− ("focus-within:", ":focus-within"),
2098− ("disabled:", ":disabled"),
2099− ("checked:", ":checked"),
2100− ("placeholder:", "::placeholder"),
2101− ("first:", ":first-child"),
2102− ("last:", ":last-child"),
2103− ("odd:", ":nth-child(odd)"),
2104− ("even:", ":nth-child(even)"),
2105− ("before:", "::before"),
2106− ("after:", "::after"),
2107− ("selection:", "::selection"),
2108− ("visited:", ":visited"),
2109− ("empty:", ":empty"),
2110− ("target:", ":target"),
2111− ("valid:", ":valid"),
2112− ("invalid:", ":invalid"),
2113−];
2114−const RESPONSIVE_PREFIXES: &[&str] = &["sm:", "md:", "lg:", "xl:", "2xl:"];
2115−const MEDIA_PREFIXES: &[&str] = &[
2116− "dark:",
2117− "print:",
2118− "motion-safe:",
2119− "motion-reduce:",
2120− "landscape:",
2121− "portrait:",
2122−];
2123−const CONTAINER_QUERY_PREFIXES: &[&str] = &["cq-sm:", "cq-md:", "cq-lg:", "cq-xl:", "cq-2xl:"];
2124−
2125−fn is_prefixed_attr(key: &str) -> bool {
2126− PSEUDO_PREFIXES.iter().any(|&(p, _)| key.starts_with(p))
2127− || RESPONSIVE_PREFIXES.iter().any(|p| key.starts_with(p))
2128− || MEDIA_PREFIXES.iter().any(|p| key.starts_with(p))
2129− || CONTAINER_QUERY_PREFIXES.iter().any(|p| key.starts_with(p))
2130− || key.starts_with("nth:")
2131− || key.starts_with("has(")
2132−}
2133−
2134−/// `display:flex;flex-direction:column;` — base layout for `@el` and every
2135−/// semantic wrapper that behaves like a column.
2136−const FLEX_COLUMN: &str = "display:flex;flex-direction:column;";
2137−
2138−
2139−
2140−fn attrs_to_css(
2141− attrs: &[Attribute],
2142− state_prefix: &str,
2143− kind: &ElementKind,
2144− parent_kind: Option<&ElementKind>,
1743+/// Where an element is written, which its CSS depends on.
1744+struct Site<'a> {
1745+ kind: &'a ElementKind,
1746+ /// How its parent lays out its children: its `width fill`, `height
1747+ /// fill` and `shrink` compile against it.
1748+ parent: &'a Flow,
1749+ /// It has `@in-front` / `@behind` children.
21451750 has_overlay_children: bool,
2146−) -> String {
2147− let mut css = String::new();
1751+ /// A row, column or grid inside text, laid out inline.
1752+ inline: bool,
1753+ /// The page's `<body>`, which the reset already makes a column.
1754+ root: bool,
1755+}
21481756
2149− // Base element styles only for the default (non-state) pass
2150− if state_prefix.is_empty() {
2151− // Elements with @in-front / @behind children become positioning
2152− // contexts. Pushed before user attrs so an explicit `position` wins
2153− // via dedupe (only the last declaration of a property is kept).
2154− if has_overlay_children {
2155− css.push_str("position:relative;isolation:isolate;");
2156− }
2157− match kind {
2158− ElementKind::Row => css.push_str("display:flex;flex-direction:row;"),
2159− ElementKind::Column | ElementKind::El => css.push_str(FLEX_COLUMN),
2160− ElementKind::Paragraph => css.push_str("margin:0;"),
2161− ElementKind::Tag(spec) => css.push_str(spec.css),
2162− _ => {}
2163− }
2164− // Children of @carousel get scroll-snap-align and flex-shrink
2165− if parent_kind.is_some_and(|k| k.is_tag("carousel")) {
2166− css.push_str("scroll-snap-align:start;flex-shrink:0;");
1757+impl Site<'_> {
1758+ /// Where an element in a parent with the layout `layout` and the flow
1759+ /// `parent` is.
1760+ fn new<'a>(elem: &'a Element, layout: Option<Layout>, parent: &'a Flow) -> Site<'a> {
1761+ Site {
1762+ kind: &elem.kind,
1763+ parent,
1764+ has_overlay_children: has_overlay_children(elem),
1765+ inline: layout == Some(Layout::Text) && elem.kind.layout().is_container(),
1766+ root: false,
21671767 }
21681768 }
1769+}
21691770
2170− for attr in attrs {
2171− // Determine the effective key for this pass
2172− let effective_key = if state_prefix.is_empty() {
2173− if is_prefixed_attr(&attr.key) {
2174− continue;
2175− }
2176− attr.key.as_str()
2177− } else {
2178− match attr.key.strip_prefix(state_prefix) {
2179− Some(k) => k,
2180− None => continue,
2181− }
2182− };
1771+// ---------------------------------------------------------------------------
1772+// Direction: what a child's `fill` and `shrink` compile against
1773+// ---------------------------------------------------------------------------
21831774
2184− let val = attr.value.as_deref();
1775+/// The way a flex row or column lays out its children.
1776+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
1777+enum Axis {
1778+ Row,
1779+ Column,
1780+}
21851781
2186− match effective_key {
2187− // Layout
2188− "spacing" | "gap" => {
2189− if let Some(v) = val {
2190− push_css(&mut css, "gap", &css_px(v));
2191− }
2192− }
2193− "padding" => {
2194− if let Some(v) = val {
2195− push_css(&mut css, "padding", &css_px_multi(v));
2196− }
2197− }
2198− "padding-x" => {
2199− if let Some(v) = val {
2200− // Logical property covers both inline sides in one
2201− // declaration; for symmetric values this is visually
2202− // identical to padding-left/right in LTR and RTL.
2203− push_css(&mut css, "padding-inline", &css_px(v));
2204− }
2205− }
2206− "padding-y" => {
2207− if let Some(v) = val {
2208− push_css(&mut css, "padding-block", &css_px(v));
2209− }
2210− }
2211− "padding-top" => {
2212− if let Some(v) = val {
2213− push_css(&mut css, "padding-top", &css_px(v));
2214− }
2215− }
2216− "padding-bottom" => {
2217− if let Some(v) = val {
2218− push_css(&mut css, "padding-bottom", &css_px(v));
2219− }
2220− }
2221− "padding-left" => {
2222− if let Some(v) = val {
2223− push_css(&mut css, "padding-left", &css_px(v));
2224− }
2225− }
2226− "padding-right" => {
2227− if let Some(v) = val {
2228− push_css(&mut css, "padding-right", &css_px(v));
2229− }
2230− }
1782+impl Axis {
1783+ /// The direction a `flex-direction` or `flex-flow` value sets, if it
1784+ /// names one (not `var(--dir)`, which only the browser knows).
1785+ fn of_value(value: &str) -> Option<Axis> {
1786+ value.split_whitespace().find_map(|word| match word {
1787+ "row" | "row-reverse" => Some(Axis::Row),
1788+ "column" | "column-reverse" => Some(Axis::Column),
1789+ _ => None,
1790+ })
1791+ }
1792+}
22311793
2232− // Sizing
2233− "width" => {
2234− if let Some(v) = val {
2235− match v {
2236− "fill" => match parent_kind {
2237− Some(ElementKind::Row) => {
2238− push_css(&mut css, "flex", "1");
2239− push_css(&mut css, "min-width", "0");
2240− }
2241− _ => push_css(&mut css, "width", "100%"),
2242− },
2243− "shrink" => push_css(&mut css, "flex-shrink", "0"),
2244− _ => push_css(&mut css, "width", &css_px(v)),
2245− }
2246− }
2247− }
2248− "height" => {
2249− if let Some(v) = val {
2250− match v {
2251− "fill" => match parent_kind {
2252− Some(ElementKind::Column) => {
2253− push_css(&mut css, "flex", "1");
2254− push_css(&mut css, "min-height", "0");
2255− }
2256− _ => push_css(&mut css, "height", "100%"),
2257− },
2258− "shrink" => push_css(&mut css, "flex-shrink", "0"),
2259− _ => push_css(&mut css, "height", &css_px(v)),
2260− }
2261− }
2262− }
2263− "min-width" => {
2264− if let Some(v) = val {
2265− push_css(&mut css, "min-width", &css_px(v));
2266− }
2267− }
2268− "max-width" => {
2269− if let Some(v) = val {
2270− push_css(&mut css, "max-width", &css_px(v));
2271− }
2272− }
2273− "min-height" => {
2274− if let Some(v) = val {
2275− push_css(&mut css, "min-height", &css_px(v));
2276− }
2277− }
2278− "max-height" => {
2279− if let Some(v) = val {
2280− push_css(&mut css, "max-height", &css_px(v));
2281− }
2282− }
1794+/// How an element lays out its children, as its CSS sets it: the
1795+/// direction its children's `width`/`height` `fill` and `shrink` compile
1796+/// against. That is the direction of `@row` or of a column, or the one its
1797+/// own `flex-direction` (or `flex-flow`) sets, with or without media or
1798+/// container prefixes. Like elm-ui's `.r > .wf`, the rules for a direction
1799+/// set under a prefix are keyed on the element's class: `@media (...) {
1800+/// :where(.a)>.b {...} }`.
1801+#[derive(Clone, Default)]
1802+struct Flow {
1803+ /// Without a prefix; `None` when the element isn't a flex row or column
1804+ /// (a grid, text, HTML's own layout, the top of the page)
1805+ base: Option<Axis>,
1806+ /// The direction under each chain of at-rule prefixes that sets one, in
1807+ /// the order their blocks are written
1808+ changes: Vec<(Vec<usize>, Axis)>,
1809+ /// The element's generated class, which the rules for the changes are
1810+ /// keyed on
1811+ class: Option<String>,
1812+}
22831813
2284− // Alignment
2285− "center-x" => match parent_kind {
2286− Some(ElementKind::Column) | Some(ElementKind::El) => {
2287− push_css(&mut css, "align-self", "center");
2288− }
2289− _ => {
2290− push_css(&mut css, "margin-left", "auto");
2291− push_css(&mut css, "margin-right", "auto");
2292− }
2293− },
2294− "center-y" => match parent_kind {
2295− Some(ElementKind::Row) => push_css(&mut css, "align-self", "center"),
2296− _ => {
2297− push_css(&mut css, "margin-top", "auto");
2298− push_css(&mut css, "margin-bottom", "auto");
2299− }
2300− },
2301− "align-left" => match parent_kind {
2302− Some(ElementKind::Column) | Some(ElementKind::El) => {
2303− push_css(&mut css, "align-self", "flex-start");
2304− }
2305− _ => push_css(&mut css, "margin-right", "auto"),
2306− },
2307− "align-right" => match parent_kind {
2308− Some(ElementKind::Column) | Some(ElementKind::El) => {
2309− push_css(&mut css, "align-self", "flex-end");
2310− }
2311− _ => push_css(&mut css, "margin-left", "auto"),
2312− },
2313− "align-top" => match parent_kind {
2314− Some(ElementKind::Row) => push_css(&mut css, "align-self", "flex-start"),
2315− _ => push_css(&mut css, "margin-bottom", "auto"),
2316− },
2317− "align-bottom" => match parent_kind {
2318− Some(ElementKind::Row) => push_css(&mut css, "align-self", "flex-end"),
2319− _ => push_css(&mut css, "margin-top", "auto"),
2320− },
2321−
2322− // Style
2323− "border" => {
2324− if let Some(v) = val {
2325− let parts: Vec<&str> = v.splitn(2, ' ').collect();
2326− if parts.len() == 2 {
2327− push_css(
2328− &mut css,
2329− "border",
2330− &format!("{} solid {}", css_px(parts[0]), parts[1]),
2331− );
2332− } else {
2333− push_css(
2334− &mut css,
2335− "border",
2336− &format!("{} solid currentColor", css_px(parts[0])),
2337− );
2338− }
2339− }
2340− }
2341− "border-top" | "border-bottom" | "border-left" | "border-right" => {
2342− if let Some(v) = val {
2343− let parts: Vec<&str> = v.splitn(2, ' ').collect();
2344− if parts.len() == 2 {
2345− push_css(
2346− &mut css,
2347− effective_key,
2348− &format!("{} solid {}", css_px(parts[0]), parts[1]),
2349− );
2350− } else {
2351− push_css(
2352− &mut css,
2353− effective_key,
2354− &format!("{} solid currentColor", css_px(parts[0])),
2355− );
2356− }
2357− }
2358− }
2359− "rounded" => {
2360− if let Some(v) = val {
2361− push_css(&mut css, "border-radius", &css_px(v));
2362− }
2363− }
2364− "bold" => push_css(&mut css, "font-weight", "bold"),
2365− "italic" => push_css(&mut css, "font-style", "italic"),
2366− "underline" => push_css(&mut css, "text-decoration", "underline"),
2367− "size" => {
2368− if let Some(v) = val {
2369− push_css(&mut css, "font-size", &css_px(v));
2370− }
1814+impl Flow {
1815+ fn of(elem: &Element) -> Flow {
1816+ let mut base = match elem.kind.layout() {
1817+ Layout::Row => Axis::Row,
1818+ Layout::Column => Axis::Column,
1819+ _ => return Flow::default(),
1820+ };
1821+ let mut changes: Vec<(Vec<usize>, Axis)> = Vec::new();
1822+ for attr in elem.attrs.iter().filter(|a| !a.html) {
1823+ let (condition, name) = Condition::of(&attr.key);
1824+ if !matches!(name, "flex-direction" | "flex-flow") || !condition.selector.is_empty() {
1825+ continue;
23711826 }
2372− "font" => {
2373− if let Some(v) = val {
2374− // `font "Inter, sans-serif"` quotes a whole font stack so
2375− // its commas don't split the attribute list.
2376− let v = match v.strip_prefix('"').and_then(|v| v.strip_suffix('"')) {
2377− Some(stack) if stack.contains(',') => stack,
2378− _ => v,
2379− };
2380− push_css(&mut css, "font-family", v);
2381− }
1827+ let Some(axis) = attr.value.as_deref().and_then(Axis::of_value) else {
1828+ continue;
1829+ };
1830+ if condition.at.is_empty() {
1831+ base = axis;
1832+ } else {
1833+ // The later one wins, as in the CSS
1834+ changes.retain(|(at, _)| *at != condition.at);
1835+ changes.push((condition.at, axis));
23821836 }
1837+ }
1838+ changes.sort_by_key(|(at, _)| at_order(at));
1839+ Flow {
1840+ base: Some(base),
1841+ changes,
1842+ class: None,
1843+ }
1844+ }
23831845
2384− // Typography
2385− "line-height" => {
2386− if let Some(v) = val {
2387− push_css(&mut css, "line-height", &css_line_height(v));
2388− }
2389− }
2390− "letter-spacing" => {
2391− if let Some(v) = val {
2392− push_css(&mut css, "letter-spacing", &css_px(v));
2393− }
2394− }
1846+ /// The direction under the at-rules `at`: the latest one set among
1847+ /// the conditions that hold there (`md:` holds at `lg:`), else the one
1848+ /// without a prefix.
1849+ fn at(&self, at: &[usize]) -> Option<Axis> {
1850+ let base = self.base?;
1851+ let here = Condition::at_only(at);
1852+ let changed = self
1853+ .changes
1854+ .iter()
1855+ .rev()
1856+ .find(|(chain, _)| Condition::at_only(chain).holds_at(&here))
1857+ .map(|&(_, axis)| axis);
1858+ Some(changed.unwrap_or(base))
1859+ }
1860+}
23951861
2396− // Overflow & positioning
2397− "top" => {
2398− if let Some(v) = val {
2399− push_css(&mut css, "top", &css_px(v));
2400− }
2401− }
2402− "right" => {
2403− if let Some(v) = val {
2404− push_css(&mut css, "right", &css_px(v));
2405− }
2406− }
2407− "bottom" => {
2408− if let Some(v) = val {
2409− push_css(&mut css, "bottom", &css_px(v));
2410− }
2411− }
2412− "left" => {
2413− if let Some(v) = val {
2414− push_css(&mut css, "left", &css_px(v));
2415− }
2416− }
1862+/// `width` or `height`.
1863+#[derive(Clone, Copy, PartialEq, Eq)]
1864+enum Dim {
1865+ Width,
1866+ Height,
1867+}
24171868
2418− // Display & visibility
2419− "hidden" => push_css(&mut css, "display", "none"),
1869+/// What a `width` or `height` says.
1870+#[derive(Clone, Copy, PartialEq, Eq)]
1871+enum Size {
1872+ Fill,
1873+ Shrink,
1874+ /// A size of its own (`width 300`)
1875+ Set,
1876+}
24201877
2421− // Effects
2422− "shadow" => {
2423− if let Some(v) = val {
2424− push_css(&mut css, "box-shadow", v);
2425− }
2426− }
1878+impl Size {
1879+ fn of(value: &str) -> Size {
1880+ match value.trim() {
1881+ "fill" => Size::Fill,
1882+ "shrink" => Size::Shrink,
1883+ _ => Size::Set,
1884+ }
1885+ }
1886+}
24271887
2428− // Flow
2429− "wrap" => push_css(&mut css, "flex-wrap", "wrap"),
2430− "gap-x" => {
2431− if let Some(v) = val {
2432− push_css(&mut css, "column-gap", &css_px(v));
2433− }
2434− }
2435− "gap-y" => {
2436− if let Some(v) = val {
2437− push_css(&mut css, "row-gap", &css_px(v));
2438− }
2439− }
1888+/// The declarations `fill` and `shrink` make in a parent laid out along
1889+/// `axis` (`None`: not a flex row or column). Along the parent's direction,
1890+/// `fill` takes the remaining space and `shrink` keeps the content's size;
1891+/// across it (or outside flex), `fill` is the full size and `shrink` fits
1892+/// the content.
1893+fn sizing(dim: Dim, size: Size, axis: Option<Axis>) -> &'static [(&'static str, &'static str)] {
1894+ match (dim, size, axis) {
1895+ (_, Size::Set, _) => &[],
1896+ (Dim::Width, Size::Fill, Some(Axis::Row)) => &[("flex", "1"), ("min-width", "0")],
1897+ (Dim::Width, Size::Fill, _) => &[("width", "100%")],
1898+ (Dim::Width, Size::Shrink, Some(Axis::Row)) => &[("flex-shrink", "0")],
1899+ (Dim::Width, Size::Shrink, _) => &[("width", "fit-content")],
1900+ (Dim::Height, Size::Fill, Some(Axis::Column)) => &[("flex", "1"), ("min-height", "0")],
1901+ (Dim::Height, Size::Fill, _) => &[("height", "100%")],
1902+ (Dim::Height, Size::Shrink, Some(Axis::Column)) => &[("flex-shrink", "0")],
1903+ (Dim::Height, Size::Shrink, _) => &[("height", "fit-content")],
1904+ }
1905+}
24401906
2441− // Grid
2442− "grid" => {
2443− push_css(&mut css, "display", "grid");
2444− }
2445− "grid-cols" => {
2446− if let Some(v) = val {
2447− if let Ok(n) = v.parse::<u32>() {
2448− push_css(
2449− &mut css,
2450− "grid-template-columns",
2451− &format!("repeat({},1fr)", n),
2452− );
2453− } else {
2454− push_css(&mut css, "grid-template-columns", v);
2455− }
2456− }
2457− }
2458− "grid-rows" => {
2459− if let Some(v) = val {
2460− if let Ok(n) = v.parse::<u32>() {
2461− push_css(
2462− &mut css,
2463− "grid-template-rows",
2464− &format!("repeat({},1fr)", n),
2465− );
2466− } else {
2467− push_css(&mut css, "grid-template-rows", v);
2468− }
2469− }
2470− }
2471− "col-span" => {
2472− if let Some(v) = val {
2473− push_css(&mut css, "grid-column", &format!("span {}", v));
2474− }
2475− }
2476− "row-span" => {
2477− if let Some(v) = val {
2478− push_css(&mut css, "grid-row", &format!("span {}", v));
2479− }
2480− }
1907+/// Every property `fill` and `shrink` of `dim` can set, with its initial
1908+/// value (`flex` covers `flex-shrink`).
1909+fn sizing_properties(dim: Dim) -> [(&'static str, &'static str); 3] {
1910+ match dim {
1911+ Dim::Width => [
1912+ ("flex", "0 1 auto"),
1913+ ("min-width", "auto"),
1914+ ("width", "auto"),
1915+ ],
1916+ Dim::Height => [
1917+ ("flex", "0 1 auto"),
1918+ ("min-height", "auto"),
1919+ ("height", "auto"),
1920+ ],
1921+ }
1922+}
24811923
2482− // CSS containment for rendering performance
2483− "contain" => {
2484− if let Some(v) = val {
2485− push_css(&mut css, "contain", v);
2486− } else {
2487− push_css(&mut css, "contain", "layout style paint");
2488− }
2489− }
2490− "content-visibility" => {
2491− if let Some(v) = val {
2492− push_css(&mut css, "content-visibility", v);
2493− } else {
2494− push_css(&mut css, "content-visibility", "auto");
2495− }
2496− }
1924+/// What an element's attributes under some prefixes say about its size.
1925+#[derive(Default)]
1926+struct Sizes {
1927+ /// The last `width` and `height`
1928+ width: Option<Size>,
1929+ height: Option<Size>,
1930+ /// A `fill` or `shrink` for the width / height is among them (a later
1931+ /// size may replace it)
1932+ width_word: bool,
1933+ height_word: bool,
1934+ /// It writes `flex`, one of its longhands (`flex-grow`, `flex-shrink`,
1935+ /// `flex-basis`), `min-width` or `min-height` itself
1936+ flex: bool,
1937+ flex_grow: bool,
1938+ flex_shrink: bool,
1939+ flex_basis: bool,
1940+ min_width: bool,
1941+ min_height: bool,
1942+}
24971943
2498− // Outline (like border but doesn't affect layout)
2499− "outline" => {
2500− if let Some(v) = val {
2501− let parts: Vec<&str> = v.splitn(2, ' ').collect();
2502− if parts.len() == 2 {
2503− push_css(
2504− &mut css,
2505− "outline",
2506− &format!("{} solid {}", css_px(parts[0]), parts[1]),
2507− );
2508− } else {
2509− push_css(
2510− &mut css,
2511− "outline",
2512− &format!("{} solid currentColor", css_px(parts[0])),
2513− );
1944+impl Sizes {
1945+ /// Read the attributes under the conditions that hold wherever `at`
1946+ /// does, a later condition over an earlier one.
1947+ fn of(attrs: &[Attribute], at: &Condition) -> Sizes {
1948+ let mut sizes = Sizes::default();
1949+ let mut read: Vec<(Condition, &str, &str)> = Vec::new();
1950+ for attr in attrs.iter().filter(|a| !a.html) {
1951+ let (condition, name) = Condition::of(&attr.key);
1952+ let Some(value) = attr.value.as_deref().filter(|v| !v.trim().is_empty()) else {
1953+ continue;
1954+ };
1955+ if condition.holds_at(at) {
1956+ read.push((condition, name, value));
1957+ }
1958+ }
1959+ read.sort_by_cached_key(|(condition, _, _)| condition.order());
1960+ for (_, name, value) in read {
1961+ match name {
1962+ "width" => {
1963+ let size = Size::of(value);
1964+ sizes.width = Some(size);
1965+ sizes.width_word |= size != Size::Set;
1966+ }
1967+ "height" => {
1968+ let size = Size::of(value);
1969+ sizes.height = Some(size);
1970+ sizes.height_word |= size != Size::Set;
1971+ }
1972+ "flex" => sizes.flex = true,
1973+ "flex-grow" => sizes.flex_grow = true,
1974+ "flex-shrink" => sizes.flex_shrink = true,
1975+ "flex-basis" => sizes.flex_basis = true,
1976+ "min-width" => sizes.min_width = true,
1977+ "min-height" => sizes.min_height = true,
1978+ _ => {}
1979+ }
1980+ }
1981+ sizes
1982+ }
1983+
1984+ /// The element writes `property` itself: a layout word leaves it alone.
1985+ fn writes(&self, property: &str) -> bool {
1986+ match property {
1987+ "flex" => self.flex,
1988+ "flex-grow" => self.flex || self.flex_grow,
1989+ "flex-shrink" => self.flex || self.flex_shrink,
1990+ "flex-basis" => self.flex || self.flex_basis,
1991+ "min-width" => self.min_width,
1992+ "min-height" => self.min_height,
1993+ "width" => self.width == Some(Size::Set),
1994+ "height" => self.height == Some(Size::Set),
1995+ _ => false,
1996+ }
1997+ }
1998+
1999+ /// Write a layout word's `property: value`, unless the element writes
2000+ /// the property itself. When it writes some of `flex`'s longhands, a
2001+ /// `flex` is written as the others (`flex-shrink 0, width fill` still
2002+ /// grows).
2003+ fn push(&self, css: &mut String, property: &str, value: &str) {
2004+ if property == "flex" && !self.flex {
2005+ let longhands = match value {
2006+ "1" => [
2007+ ("flex-grow", "1"),
2008+ ("flex-shrink", "1"),
2009+ ("flex-basis", "0%"),
2010+ ],
2011+ // The reset, `0 1 auto`
2012+ _ => [
2013+ ("flex-grow", "0"),
2014+ ("flex-shrink", "1"),
2015+ ("flex-basis", "auto"),
2016+ ],
2017+ };
2018+ if longhands.iter().any(|&(p, _)| self.writes(p)) {
2019+ for (longhand, value) in longhands {
2020+ if !self.writes(longhand) {
2021+ push_css(css, longhand, value);
25142022 }
25152023 }
2024+ return;
25162025 }
2026+ }
2027+ if !self.writes(property) {
2028+ push_css(css, property, value);
2029+ }
2030+ }
2031+}
25172032
2518− // Logical properties (i18n-aware)
2519− "padding-inline" => {
2520− if let Some(v) = val {
2521− push_css(&mut css, "padding-inline", &css_px_multi(v));
2522− }
2523− }
2524− "padding-block" => {
2525− if let Some(v) = val {
2526− push_css(&mut css, "padding-block", &css_px_multi(v));
2527− }
2528− }
2529− "margin-inline" => {
2530− if let Some(v) = val {
2531− push_css(&mut css, "margin-inline", &css_px_multi(v));
2532− }
2533− }
2534− "margin-block" => {
2535− if let Some(v) = val {
2536− push_css(&mut css, "margin-block", &css_px_multi(v));
2537− }
2538− }
2033+/// The rule that gives an element's `fill` and `shrink`, as its attributes
2034+/// under the at-rules `at` set them, their meaning in a parent laid out
2035+/// along `axis`. Every other property a layout word could have set is put
2036+/// back to its initial value, so the rule is right whichever earlier rule
2037+/// it overrides. Properties the element writes itself are left alone.
2038+fn sizing_rule(attrs: &[Attribute], at: &[usize], axis: Axis) -> String {
2039+ let sizes = Sizes::of(attrs, &Condition::at_only(at));
2040+ let mut sets: Vec<(&str, &str)> = Vec::new();
2041+ let mut resets: Vec<(&str, &str)> = Vec::new();
2042+ for (dim, size, word) in [
2043+ (Dim::Width, sizes.width, sizes.width_word),
2044+ (Dim::Height, sizes.height, sizes.height_word),
2045+ ] {
2046+ if !word {
2047+ continue;
2048+ }
2049+ if let Some(size) = size {
2050+ sets.extend_from_slice(sizing(dim, size, Some(axis)));
2051+ }
2052+ resets.extend_from_slice(&sizing_properties(dim));
2053+ }
2054+ let mut css = String::new();
2055+ let mut written: Vec<&str> = Vec::new();
2056+ for &(property, value) in &resets {
2057+ if sets.iter().any(|&(p, _)| p == property) || written.contains(&property) {
2058+ continue;
2059+ }
2060+ written.push(property);
2061+ sizes.push(&mut css, property, value);
2062+ }
2063+ for &(property, value) in &sets {
2064+ sizes.push(&mut css, property, value);
2065+ }
2066+ css
2067+}
25392068
2540− // Logical property start/end variants
2541− "padding-inline-start"
2542− | "padding-inline-end"
2543− | "padding-block-start"
2544− | "padding-block-end"
2545− | "margin-inline-start"
2546− | "margin-inline-end"
2547− | "margin-block-start"
2548− | "margin-block-end" => {
2549− if let Some(v) = val {
2550− push_css(&mut css, effective_key, &css_px(v));
2551− }
2552− }
2069+/// The rules an element's `fill` and `shrink` need under each chain of
2070+/// at-rules where the direction of `flow` (its parent's) changes: `(at,
2071+/// body)`.
2072+fn sizing_changes(attrs: &[Attribute], flow: &Flow) -> Vec<(Vec<usize>, String)> {
2073+ flow.changes
2074+ .iter()
2075+ .map(|(at, axis)| (at.clone(), sizing_rule(attrs, at, *axis)))
2076+ .filter(|(_, body)| !body.is_empty())
2077+ .collect()
2078+}
25532079
2554− // Logical inset
2555− "inset-inline" | "inset-block" => {
2556− if let Some(v) = val {
2557− push_css(&mut css, effective_key, &css_px_multi(v));
2558− }
2559− }
2560− "inset-inline-start" | "inset-inline-end" | "inset-block-start" | "inset-block-end" => {
2561− if let Some(v) = val {
2562− push_css(&mut css, effective_key, &css_px(v));
2563− }
2564− }
2080+/// An element's generated class, with the rules keyed on its parent's
2081+/// class that its `fill` and `shrink` need where the parent's direction
2082+/// changes under a prefix (see [`Flow`]): `:where(.a)>.b`, one class of
2083+/// specificity like any class rule.
2084+fn element_class(elem: &Element, site: &Site, styles: &mut StyleCollector) -> Option<String> {
2085+ let as_child = match site.parent.class {
2086+ Some(_) => sizing_changes(&elem.attrs, site.parent),
2087+ None => Vec::new(),
2088+ };
2089+ // Two elements with the same CSS but different rules keyed on them
2090+ // need two classes
2091+ let mut distinct = String::new();
2092+ for (at, body) in &as_child {
2093+ distinct.push_str(&format!("<{:?}{}", at, body));
2094+ }
2095+ let class = compute_class(&elem.attrs, site, styles, distinct)?;
2096+ if let Some(parent) = &site.parent.class {
2097+ for (at, body) in as_child {
2098+ styles.add_keyed(at, format!(":where(.{})>.{}", parent, class), body);
2099+ }
2100+ }
2101+ Some(class)
2102+}
25652103
2566− // Logical border
2567− "border-inline"
2568− | "border-block"
2569− | "border-inline-start"
2570− | "border-inline-end"
2571− | "border-block-start"
2572− | "border-block-end" => {
2573− if let Some(v) = val {
2574− push_css(&mut css, effective_key, v);
2575− }
2576− }
2104+/// The `display` of a layout (nothing for text, native and void elements,
2105+/// which keep HTML's own).
2106+fn layout_css(layout: Layout, inline: bool) -> &'static str {
2107+ match (layout, inline) {
2108+ (Layout::Column, false) => "display:flex;flex-direction:column;",
2109+ (Layout::Column, true) => "display:inline-flex;flex-direction:column;",
2110+ (Layout::Row, false) => "display:flex;flex-direction:row;",
2111+ (Layout::Row, true) => "display:inline-flex;flex-direction:row;",
2112+ (Layout::Grid, false) => "display:grid;",
2113+ (Layout::Grid, true) => "display:inline-grid;",
2114+ _ => "",
2115+ }
2116+}
25772117
2578− // Logical border-radius
2579− "border-start-start-radius"
2580− | "border-start-end-radius"
2581− | "border-end-start-radius"
2582− | "border-end-end-radius" => {
2583− if let Some(v) = val {
2584− push_css(&mut css, effective_key, &css_px(v));
2585− }
2586− }
2118+/// The declarations of the attributes under `condition` (the defaults of
2119+/// the element's kind are [`default_css`]'s).
2120+fn attrs_to_css(attrs: &[Attribute], condition: &Condition, site: &Site) -> String {
2121+ let mut css = String::new();
2122+ // The auto margins of `center-x`, `align-left`, ..., written at the end
2123+ let mut aligned = String::new();
2124+ let kind = site.kind;
2125+ // Under `children:` the styles go on the children, whose parent is this
2126+ // element: htmlang's words that place an element in its parent are an
2127+ // error there (the parser reports them), and left out
2128+ let on_children = condition.on_children();
2129+ let inside = condition.inside().is_some();
2130+ // The direction `fill` and `shrink` compile against
2131+ let axis = site.parent.at(&condition.at);
2132+
2133+ // htmlang's words for laying out children (`spacing`, `wrap`,
2134+ // `grid-cols`) mean nothing on an element that doesn't lay out its
2135+ // children, which the parser reports; they are left out. Under
2136+ // `children:` they go on the children, whose layout isn't known here.
2137+ let lays_out_children = kind.layout().is_container() || on_children;
2138+ fn under<'k>(key: &'k str, condition: &Condition) -> Option<&'k str> {
2139+ let (c, name) = Condition::of(key);
2140+ (c == *condition).then_some(name)
2141+ }
2142+
2143+ for (index, attr) in attrs.iter().enumerate() {
2144+ if attr.html {
2145+ continue;
2146+ }
2147+ let Some(effective_key) = under(&attr.key, condition) else {
2148+ continue;
2149+ };
2150+ if on_children && crate::vocab::places_in_parent(effective_key, attr.value.as_deref()) {
2151+ continue;
2152+ }
2153+ // Under an element prefix (`@td:`) the styles go on elements whose
2154+ // layout and parent aren't known here: htmlang's own words are an
2155+ // error there (the parser reports them), and left out
2156+ if inside && crate::vocab::is_htmlang_word(effective_key, attr.value.as_deref()) {
2157+ continue;
2158+ }
25872159
2588− // Logical scroll margins & padding
2589− "scroll-margin-inline"
2590− | "scroll-margin-block"
2591− | "scroll-padding-inline"
2592− | "scroll-padding-block" => {
2593− if let Some(v) = val {
2594− push_css(&mut css, effective_key, &css_px_multi(v));
2595− }
2596− }
2160+ let val = attr.value.as_deref();
2161+ // A style whose value came out empty (a field a record doesn't
2162+ // have, `${if()}` without its other branch) is left out
2163+ if val.is_some_and(|v| v.trim().is_empty()) {
2164+ continue;
2165+ }
25972166
2598− // Logical sizing
2599− "inline-size" | "block-size" | "min-inline-size" | "max-inline-size"
2600− | "min-block-size" | "max-block-size" => {
2167+ match effective_key {
2168+ // htmlang's own words: they lay out children or place the
2169+ // element in its parent, and mean more than one CSS property
2170+ "spacing" if !lays_out_children => {}
2171+ "spacing" => {
26012172 if let Some(v) = val {
2602− push_css(&mut css, effective_key, &css_px(v));
2173+ push_css(&mut css, "gap", &with_px("gap", v));
26032174 }
26042175 }
26052176
2606− // Margin
2607− "margin" => {
2608− if let Some(v) = val {
2609− push_css(&mut css, "margin", &css_px_multi(v));
2610− }
2611− }
2612− "margin-x" => {
2613− if let Some(v) = val {
2614− push_css(&mut css, "margin-inline", &css_px(v));
2615− }
2616− }
2617− "margin-y" => {
2618− if let Some(v) = val {
2619− push_css(&mut css, "margin-block", &css_px(v));
2177+ // Sizing: `fill` and `shrink` compile against the parent's
2178+ // direction. Only the last `width` (`height`) counts, as for
2179+ // any style written twice.
2180+ "width" | "height" if val.is_some_and(|v| Size::of(v) != Size::Set) => {
2181+ let later = attrs[index + 1..].iter().any(|a| {
2182+ !a.html
2183+ && under(&a.key, condition) == Some(effective_key)
2184+ && a.value.as_deref().is_some_and(|v| !v.trim().is_empty())
2185+ });
2186+ if later {
2187+ continue;
26202188 }
2621− }
2622−
2623− // Container queries
2624− "container" => {
2625− push_css(&mut css, "container-type", "inline-size");
2626− }
2627−
2628− // Inset (shorthand for top/right/bottom/left)
2629− "inset" => {
2630− if let Some(v) = val {
2631− push_css(&mut css, "inset", &css_px(v));
2189+ let dim = if effective_key == "width" {
2190+ Dim::Width
2191+ } else {
2192+ Dim::Height
2193+ };
2194+ let size = Size::of(val.unwrap_or_default());
2195+ // What the element writes itself, which a layout word
2196+ // leaves alone
2197+ let sizes = Sizes::of(attrs, condition);
2198+ for &(property, value) in sizing(dim, size, axis) {
2199+ sizes.push(&mut css, property, value);
2200+ }
2201+ }
2202+
2203+ // A size of its own under a prefix, where a `fill` or
2204+ // `shrink` that sets `flex` (along a flex parent's direction)
2205+ // holds too: the word's `flex` and minimum are put back, so the
2206+ // size is the one the element gets (`width fill, lg:width 200`
2207+ // in a row)
2208+ "width" | "height"
2209+ if *condition != Condition::default()
2210+ && attrs.iter().any(|a| {
2211+ let (c, name) = Condition::of(&a.key);
2212+ let along = match site.parent.at(&c.at) {
2213+ Some(Axis::Row) => name == "width",
2214+ Some(Axis::Column) => name == "height",
2215+ None => false,
2216+ };
2217+ !a.html
2218+ && name == effective_key
2219+ && along
2220+ && c != *condition
2221+ && c.holds_at(condition)
2222+ && a.value
2223+ .as_deref()
2224+ .is_some_and(|v| !v.trim().is_empty() && Size::of(v) != Size::Set)
2225+ }) =>
2226+ {
2227+ let dim = if effective_key == "width" {
2228+ Dim::Width
2229+ } else {
2230+ Dim::Height
2231+ };
2232+ let sizes = Sizes::of(attrs, condition);
2233+ for (property, value) in sizing_properties(dim) {
2234+ if property != effective_key {
2235+ sizes.push(&mut css, property, value);
2236+ }
26322237 }
2633− }
2634−
2635− // Table
2636− "border-spacing" => {
26372238 if let Some(v) = val {
2638− push_css(&mut css, "border-spacing", &css_px(v));
2239+ push_css(&mut css, effective_key, &with_px(effective_key, v));
26392240 }
26402241 }
26412242
2642− // Text decoration
2643− "text-decoration-thickness" => {
2644− if let Some(v) = val {
2645− push_css(&mut css, "text-decoration-thickness", &css_px(v));
2646− }
2243+ // Alignment: auto margins, which work along either direction.
2244+ // They are written last, so a `margin` on the same element
2245+ // keeps its other sides (`center-x, margin 20`)
2246+ "center-x" => {
2247+ push_css(&mut aligned, "margin-left", "auto");
2248+ push_css(&mut aligned, "margin-right", "auto");
26472249 }
2648− "text-underline-offset" => {
2649− if let Some(v) = val {
2650− push_css(&mut css, "text-underline-offset", &css_px(v));
2651− }
2250+ "center-y" => {
2251+ push_css(&mut aligned, "margin-top", "auto");
2252+ push_css(&mut aligned, "margin-bottom", "auto");
26522253 }
2254+ "align-left" => push_css(&mut aligned, "margin-right", "auto"),
2255+ "align-right" => push_css(&mut aligned, "margin-left", "auto"),
2256+ "align-top" => push_css(&mut aligned, "margin-bottom", "auto"),
2257+ "align-bottom" => push_css(&mut aligned, "margin-top", "auto"),
26532258
2654− // Multi-column
2655− "column-width" => {
2656− if let Some(v) = val {
2657− push_css(&mut css, "column-width", &css_px(v));
2658− }
2659− }
2259+ "wrap" if lays_out_children => push_css(&mut css, "flex-wrap", "wrap"),
2260+ "wrap" => {}
26602261
2661− // New CSS properties
2662− "column-gap" => {
2663− if let Some(v) = val {
2664− push_css(&mut css, "column-gap", &css_px(v));
2665− }
2666− }
2667− "text-indent" => {
2668− if let Some(v) = val {
2669− push_css(&mut css, "text-indent", &css_px(v));
2670− }
2671− }
2672− "flex-basis" => {
2673− if let Some(v) = val {
2674− push_css(&mut css, "flex-basis", &css_px(v));
2675− }
2676− }
2677− "scroll-margin" => {
2678− if let Some(v) = val {
2679− push_css(&mut css, "scroll-margin", &css_px(v));
2680− }
2681− }
2682− "scroll-margin-top"
2683− | "scroll-margin-bottom"
2684− | "scroll-margin-left"
2685− | "scroll-margin-right" => {
2686− if let Some(v) = val {
2687− push_css(&mut css, effective_key, &css_px(v));
2688− }
2689− }
2690− "scroll-padding" => {
2691− if let Some(v) = val {
2692− push_css(&mut css, "scroll-padding", &css_px(v));
2693− }
2694− }
2695− "scroll-padding-top"
2696− | "scroll-padding-bottom"
2697− | "scroll-padding-left"
2698− | "scroll-padding-right" => {
2262+ // Grid
2263+ "grid-cols" | "grid-rows" if !lays_out_children => {}
2264+ "grid-cols" | "grid-rows" => {
26992265 if let Some(v) = val {
2700− push_css(&mut css, effective_key, &css_px(v));
2266+ let property = if effective_key == "grid-cols" {
2267+ "grid-template-columns"
2268+ } else {
2269+ "grid-template-rows"
2270+ };
2271+ match v.parse::<u32>() {
2272+ Ok(n) => push_css(&mut css, property, &format!("repeat({},1fr)", n)),
2273+ Err(_) => push_css(&mut css, property, &with_px(property, v)),
2274+ }
27012275 }
27022276 }
2703−
2704− "content" => {
2277+ "col-span" | "row-span" => {
27052278 if let Some(v) = val {
2706− // Wrap in quotes if not already quoted and not a CSS keyword
2707− if v.starts_with('"')
2708− || v.starts_with('\'')
2709− || v == "none"
2710− || v == "normal"
2711− || v.starts_with("attr(")
2712− || v.starts_with("counter(")
2713− {
2714− push_css(&mut css, "content", v);
2279+ let property = if effective_key == "col-span" {
2280+ "grid-column"
27152281 } else {
2716− push_css(&mut css, "content", &format!("\"{}\"", v));
2717− }
2282+ "grid-row"
2283+ };
2284+ push_css(&mut css, property, &format!("span {}", v));
27182285 }
27192286 }
27202287
2721− // --- CSS Shorthands ---
2722− "truncate" => {
2723− push_css(&mut css, "overflow", "hidden");
2724− push_css(&mut css, "text-overflow", "ellipsis");
2725− push_css(&mut css, "white-space", "nowrap");
2726− }
2288+ // CSS's `line-clamp` has no support yet without its
2289+ // `-webkit-` fallback, which needs a box to clamp
27272290 "line-clamp" => {
27282291 if let Some(v) = val {
27292292 push_css(&mut css, "display", "-webkit-box");
@@ -2732,76 +2295,15 @@ fn attrs_to_css(
27322295 push_css(&mut css, "overflow", "hidden");
27332296 }
27342297 }
2735− "blur" => {
2736− if let Some(v) = val {
2737− push_css(&mut css, "filter", &format!("blur({})", css_px(v)));
2738− }
2739− }
2740− "backdrop-blur" => {
2741− if let Some(v) = val {
2742− push_css(&mut css, "backdrop-filter", &format!("blur({})", css_px(v)));
2743− }
2744− }
2745− "no-scrollbar" => {
2746− push_css(&mut css, "scrollbar-width", "none");
2747− push_css(&mut css, "-ms-overflow-style", "none");
2748− }
2749− "skeleton" => {
2750− push_css(
2751− &mut css,
2752− "background",
2753− "linear-gradient(90deg,#e5e7eb 25%,#f3f4f6 50%,#e5e7eb 75%)",
2754− );
2755− push_css(&mut css, "background-size", "200% 100%");
2756− push_css(
2757− &mut css,
2758− "animation",
2759− "hl-skeleton 1.5s ease-in-out infinite",
2760− );
2761− }
2762− "gradient" => {
2763− if let Some(v) = val {
2764− // Parse: "from to [angle]" or "color1 color2 [angle]"
2765− let parts: Vec<&str> = v.split_whitespace().collect();
2766− let bg = if parts.len() >= 3
2767− && (parts[2].ends_with("deg")
2768− || parts[2].ends_with("turn")
2769− || parts[2].ends_with("rad"))
2770− {
2771− format!("linear-gradient({},{},{})", parts[2], parts[0], parts[1])
2772− } else if parts.len() >= 2 {
2773− format!("linear-gradient({},{})", parts[0], parts[1])
2774− } else {
2775− format!("linear-gradient({},transparent)", parts[0])
2776− };
2777− push_css(&mut css, "background", &bg);
2778− }
2779− }
27802298
2781− // Critical CSS hint — not CSS, handled elsewhere
2782− "critical" => {}
2783−
2784− // Identity and HTML passthrough — not CSS
2785− "id" | "class" => {}
2786− "type" | "placeholder" | "name" | "value" | "disabled" | "required" | "checked"
2787− | "for" | "action" | "method" | "autocomplete" | "min" | "max" | "step" | "pattern"
2788− | "maxlength" | "rows" | "cols" | "multiple" | "alt" | "role" | "tabindex"
2789− | "title" | "controls" | "autoplay" | "loop" | "muted" | "playsinline" | "poster"
2790− | "preload" | "loading" | "decoding" | "ordered" | "src" | "open" | "novalidate"
2791− | "low" | "high" | "optimum" | "colspan" | "rowspan" | "scope" | "inline"
2792− | "responsive" | "datetime" | "media" | "sizes" | "srcset" | "cite" | "list"
2793− | "sandbox" | "allow" | "allowfullscreen" | "referrerpolicy" | "formaction"
2794− | "formmethod" | "formtarget" | "target" | "autofocus" => {}
2795−
2796− // Any other standard CSS property is copied through, with `px`
2797− // added to bare numbers where the property takes a length.
2798− key if crate::vocab::is_css_property(key) && !crate::vocab::is_html_passthrough(key) => {
2299+ // Every other name is a CSS property (standard, custom,
2300+ // vendor-prefixed, or one htmlang doesn't know, which the
2301+ // parser warned about), written under its own name with the
2302+ // value as written, except for `px` after a bare number where
2303+ // the property takes a length
2304+ key if crate::vocab::is_property_name(key) => {
27992305 if let Some(v) = val {
2800− if crate::vocab::is_length_property(key) {
2801− push_css(&mut css, key, &css_px_multi(v));
2802− } else {
2803− push_css(&mut css, key, v);
2804− }
2306+ push_css(&mut css, key, &with_px(key, v));
28052307 }
28062308 }
28072309
@@ -2809,6 +2311,7 @@ fn attrs_to_css(
28092311 }
28102312 }
28112313
2314+ css.push_str(&aligned);
28122315 css
28132316}
28142317
@@ -2819,262 +2322,10 @@ fn push_css(css: &mut String, prop: &str, value: &str) {
28192322 css.push(';');
28202323}
28212324
2822−/// Known CSS units — if a value ends with one, skip appending `px`.
2823−/// Format a length value: a bare number gets `px` appended; anything else
2824−/// (values with units, keywords like `auto`, functions like `calc(...)`) is
2825−/// passed through unchanged.
2826−fn css_px(value: &str) -> String {
2827− let v = value.trim();
2828− if v == "0" {
2829− return "0".to_string();
2830− }
2831− let is_bare_number = !v.is_empty()
2832− && v.bytes().all(|b| b.is_ascii_digit() || matches!(b, b'.' | b'-' | b'+'))
2833− && v.parse::<f64>().is_ok();
2834− if is_bare_number {
2835− format!("{}px", v)
2836− } else {
2837− v.to_string()
2838− }
2839−}
2840−
2841−/// Rewrite literal values that match a declared CSS custom property (from
2842−/// `@theme` or `@let --name value`) to `var(--name)` references. Matches are
2843−/// anchored to CSS value boundaries so e.g. `#3b82f6` inside a longer hex or
2844−/// inside an identifier is not replaced. The `:root` block is emitted before
2845−/// this call runs, so its declarations are not affected.
2846−fn substitute_css_vars(css: &str, vars: &[(String, String)]) -> String {
2847− if css.is_empty() || vars.is_empty() {
2848− return css.to_string();
2849− }
2850− // Prefer longer values first so that if two vars share a prefix, the
2851− // longer (more specific) match wins.
2852− let mut pairs: Vec<(&str, String)> = vars
2853− .iter()
2854− .filter(|(name, value)| name.starts_with("--") && !value.is_empty())
2855− .map(|(name, value)| (value.as_str(), format!("var({})", name)))
2856− .collect();
2857− pairs.sort_by_key(|(v, _)| std::cmp::Reverse(v.len()));
2858− if pairs.is_empty() {
2859− return css.to_string();
2860− }
2861−
2862− let is_boundary_before = |b: Option<u8>| match b {
2863− None => true,
2864− Some(c) => matches!(c, b':' | b' ' | b',' | b'(' | b';' | b'{' | b'\n' | b'\t'),
2865− };
2866− let is_boundary_after = |b: Option<u8>| match b {
2867− None => true,
2868− Some(c) => matches!(c, b';' | b'}' | b',' | b' ' | b')' | b'\n' | b'\t'),
2869− };
2870−
2871− let bytes = css.as_bytes();
2872− let mut out = String::with_capacity(css.len());
2873− let mut i = 0;
2874− let mut prev: Option<u8> = None;
2875− // Only declaration values are rewritten — never selectors or at-rule
2876− // preludes such as `@media (min-width:768px)`. `blocks` records, for
2877− // each open `{`, whether it holds declarations (a style rule) or nested
2878− // rules (an at-rule like `@media` / `@layer`).
2879− let mut blocks: Vec<bool> = Vec::new();
2880− let mut prelude_start = 0;
2881− let mut in_value = false;
2882− while i < bytes.len() {
2883− match bytes[i] {
2884− b'{' => {
2885− let prelude = css[prelude_start..i].trim_start();
2886− blocks.push(!prelude.starts_with('@'));
2887− in_value = false;
2888− prelude_start = i + 1;
2889− }
2890− b'}' => {
2891− blocks.pop();
2892− in_value = false;
2893− prelude_start = i + 1;
2894− }
2895− b';' => {
2896− in_value = false;
2897− prelude_start = i + 1;
2898− }
2899− b':' if blocks.last() == Some(&true) => in_value = true,
2900− _ => {}
2901− }
2902− if in_value && is_boundary_before(prev) {
2903− let mut matched = false;
2904− for (val, repl) in &pairs {
2905− let vb = val.as_bytes();
2906− if i + vb.len() <= bytes.len() && &bytes[i..i + vb.len()] == vb {
2907− let next = bytes.get(i + vb.len()).copied();
2908− if is_boundary_after(next) {
2909− out.push_str(repl);
2910− prev = repl.as_bytes().last().copied();
2911− i += vb.len();
2912− matched = true;
2913− break;
2914− }
2915− }
2916− }
2917− if matched {
2918− continue;
2919− }
2920− }
2921− // Advance by one UTF-8 code point.
2922− let start = i;
2923− i += 1;
2924− while i < bytes.len() && (bytes[i] & 0xC0) == 0x80 {
2925− i += 1;
2926− }
2927− out.push_str(&css[start..i]);
2928− prev = bytes.get(i - 1).copied();
2929− }
2930− out
2931−}
2932−
2933−/// Scan generated CSS for literal property values that repeat often enough
2934−/// that substituting them with an auto-named custom property would reduce
2935−/// total byte count. Returns the rewritten CSS and any new vars that should
2936−/// be appended to `:root`.
2937−///
2938−/// The algorithm only promotes a value if it strictly saves bytes after
2939−/// accounting for the `--xN:value;` declaration overhead plus the
2940−/// `var(--xN)` reference cost at each call site. Values that are already
2941−/// `var(...)` references or contain `var(` calls are skipped so we never
2942−/// nest references. Names avoid collisions with `existing_vars`.
2943−fn auto_extract_repeats(
2944− css: &str,
2945− existing_vars: &[(String, String)],
2946−) -> (String, Vec<(String, String)>) {
2947− if css.is_empty() {
2948− return (css.to_string(), Vec::new());
2949− }
2950− // Count occurrences of each distinct property value (the text between
2951− // `:` and the next `;` or `}` at the top level of a declaration block,
2952− // ignoring balanced parentheses so that e.g. `rgba(...)` stays intact).
2953− let bytes = css.as_bytes();
2954− let mut counts: HashMap<String, usize> = HashMap::new();
2955− let mut depth: i32 = 0;
2956− let mut i = 0;
2957− while i < bytes.len() {
2958− match bytes[i] {
2959− b'{' => {
2960− depth += 1;
2961− i += 1;
2962− continue;
2963− }
2964− b'}' => {
2965− if depth > 0 {
2966− depth -= 1;
2967− }
2968− i += 1;
2969− continue;
2970− }
2971− _ => {}
2972− }
2973− if depth > 0 && bytes[i] == b':' {
2974− // Skip past `:` then walk to the terminator.
2975− let start = i + 1;
2976− let mut end = start;
2977− let mut pdepth = 0i32;
2978− while end < bytes.len() {
2979− match bytes[end] {
2980− b'(' => pdepth += 1,
2981− b')' if pdepth > 0 => pdepth -= 1,
2982− b';' | b'}' if pdepth == 0 => break,
2983− b'{' if pdepth == 0 => break,
2984− _ => {}
2985− }
2986− end += 1;
2987− }
2988− let val = css[start..end].trim();
2989− if !val.is_empty() && !val.starts_with("var(") && !val.contains("var(") {
2990− *counts.entry(val.to_string()).or_default() += 1;
2991− }
2992− i = end;
2993− continue;
2994− }
2995− i += 1;
2996− }
2997−
2998− // Decide which values are worth extracting. A value of length L appearing
2999− // N times costs N*L bytes inline; promoting it costs (L + 6) for the
3000− // `--hK:V;` declaration plus N * ref_len for the call sites. We estimate
3001− // ref_len optimistically as `var(--h0)` (9 bytes) and fall back to 10 for
3002− // two-digit indices, which only affects very large extraction counts.
3003− let existing: std::collections::HashSet<&str> =
3004− existing_vars.iter().map(|(n, _)| n.as_str()).collect();
3005− let mut candidates: Vec<(String, usize)> =
3006− counts.into_iter().filter(|(_, n)| *n >= 2).collect();
3007− // Stable, deterministic ordering — longest values first, tiebreak by text.
3008− candidates.sort_by(|a, b| b.0.len().cmp(&a.0.len()).then_with(|| a.0.cmp(&b.0)));
3009−
3010− let mut extracted: Vec<(String, String)> = Vec::new();
3011− let mut next_idx: usize = 0;
3012− for (value, n) in candidates {
3013− let l = value.len();
3014− // Allocate the next unused `--hN` name.
3015− let (name, ref_len) = loop {
3016− let candidate = format!("--h{}", next_idx);
3017− next_idx += 1;
3018− let rl = candidate.len() + 6; // `var(` + name + `)`
3019− if !existing.contains(candidate.as_str())
3020− && !extracted.iter().any(|(n, _)| *n == candidate)
3021− {
3022− break (candidate, rl);
3023− }
3024− };
3025− // Skip if promotion would not strictly reduce byte count.
3026− // Before: n * l bytes. After: (l + name.len() + 2) for the :root
3027− // declaration (`<name>:<value>;`) plus n * ref_len for the sites.
3028− let decl_overhead = l + name.len() + 2;
3029− let before = n * l;
3030− let after = decl_overhead + n * ref_len;
3031− if after < before {
3032− extracted.push((name, value));
3033− } else {
3034− // Rewind the index so the next value can reuse this slot.
3035− next_idx -= 1;
3036− }
3037− }
3038−
3039− if extracted.is_empty() {
3040− return (css.to_string(), Vec::new());
3041− }
3042− let new_css = substitute_css_vars(css, &extracted);
3043− (new_css, extracted)
3044−}
3045−
3046−/// Format a `line-height` value. CSS accepts either a unitless multiplier
3047−/// (e.g. `1.5`) or a length (e.g. `24px`). Plain integers in htmlang source
3048−/// are ambiguous: `[line-height 24]` was historically emitted as `24` (which
3049−/// CSS interprets as 24× font-size — almost never what anyone wants). Treat
3050−/// integers ≥ 2 as pixel lengths; anything with a decimal, an existing unit,
3051−/// or the value `0`/`1` passes through unchanged.
3052−fn css_line_height(value: &str) -> String {
3053− let v = value.trim();
3054− if v == "0" || v == "1" {
3055− return v.to_string();
3056− }
3057− // Plain integer — treat as pixel length. Decimals, units, keywords and
3058− // functions pass through.
3059− if !v.is_empty() && v.chars().all(|c| c.is_ascii_digit()) {
3060− return format!("{}px", v);
3061− }
3062− v.to_string()
3063−}
3064−
3065−/// Format multiple space-separated values, each getting px if needed.
3066−fn css_px_multi(value: &str) -> String {
3067− value
3068− .split_whitespace()
3069− .map(css_px)
3070− .collect::<Vec<_>>()
3071− .join(" ")
3072−}
3073−
30742325fn extract_id_class(attrs: &[Attribute]) -> (Option<String>, Option<String>) {
30752326 let mut id = None;
30762327 let mut class = None;
3077− for attr in attrs {
2328+ for attr in attrs.iter().filter(|a| a.html) {
30782329 match attr.key.as_str() {
30792330 "id" => id = attr.value.clone(),
30802331 "class" => class = attr.value.clone(),
@@ -3084,153 +2335,6 @@ fn extract_id_class(attrs: &[Attribute]) -> (Option<String>, Option<String>) {
30842335 (id, class)
30852336}
30862337
3087−/// Read image dimensions from a local file by parsing the header bytes.
3088−/// Supports PNG, JPEG, GIF, WebP, AVIF, and SVG.
3089−fn read_image_dimensions(path: &str) -> Option<(u32, u32)> {
3090− // SVG: parse as text for viewBox/width/height attributes
3091− if path.ends_with(".svg") || path.ends_with(".SVG") {
3092− let text = std::fs::read_to_string(path).ok()?;
3093− return read_svg_dimensions(&text);
3094− }
3095−
3096− let data = std::fs::read(path).ok()?;
3097− if data.len() < 12 {
3098− return None;
3099− }
3100−
3101− // PNG: 8-byte signature, then IHDR chunk with width/height at bytes 16-23
3102− if data.len() >= 24 && data.starts_with(b"\x89PNG\r\n\x1a\n") {
3103− let w = u32::from_be_bytes([data[16], data[17], data[18], data[19]]);
3104− let h = u32::from_be_bytes([data[20], data[21], data[22], data[23]]);
3105− return Some((w, h));
3106− }
3107−
3108− // GIF: "GIF87a" or "GIF89a", width/height at bytes 6-9 (little-endian)
3109− if data.starts_with(b"GIF87a") || data.starts_with(b"GIF89a") {
3110− let w = u16::from_le_bytes([data[6], data[7]]) as u32;
3111− let h = u16::from_le_bytes([data[8], data[9]]) as u32;
3112− return Some((w, h));
3113− }
3114−
3115− // JPEG: scan for SOF0/SOF2 marker (0xFF 0xC0 or 0xFF 0xC2)
3116− if data.starts_with(b"\xff\xd8") {
3117− let mut i = 2;
3118− while i + 9 < data.len() {
3119− if data[i] != 0xFF {
3120− i += 1;
3121− continue;
3122− }
3123− let marker = data[i + 1];
3124− if marker == 0xC0 || marker == 0xC2 {
3125− let h = u16::from_be_bytes([data[i + 5], data[i + 6]]) as u32;
3126− let w = u16::from_be_bytes([data[i + 7], data[i + 8]]) as u32;
3127− return Some((w, h));
3128− }
3129− if i + 3 < data.len() {
3130− let len = u16::from_be_bytes([data[i + 2], data[i + 3]]) as usize;
3131− i += 2 + len;
3132− } else {
3133− break;
3134− }
3135− }
3136− }
3137−
3138− // WebP: "RIFF" ... "WEBP", VP8 header at byte 20
3139− if data.len() >= 30 && &data[..4] == b"RIFF" && &data[8..12] == b"WEBP" {
3140− if &data[12..16] == b"VP8 " && data.len() >= 30 {
3141− let w = u16::from_le_bytes([data[26], data[27]]) as u32 & 0x3FFF;
3142− let h = u16::from_le_bytes([data[28], data[29]]) as u32 & 0x3FFF;
3143− return Some((w, h));
3144− }
3145− if &data[12..16] == b"VP8L" && data.len() >= 25 && data[21] == 0x2F {
3146− let bits = u32::from_le_bytes([data[22], data[23], data[24], data[25]]);
3147− let w = (bits & 0x3FFF) + 1;
3148− let h = ((bits >> 14) & 0x3FFF) + 1;
3149− return Some((w, h));
3150− }
3151− }
3152−
3153− // AVIF: ISOBMFF container with "ftyp" box containing "avif"/"avis" brand,
3154− // then "ispe" box with width/height
3155− if data.len() >= 12 && &data[4..8] == b"ftyp" {
3156− let brand = &data[8..12];
3157− if brand == b"avif" || brand == b"avis" || brand == b"mif1" {
3158− return read_avif_dimensions(&data);
3159− }
3160− }
3161−
3162− None
3163−}
3164−
3165−/// Parse SVG viewBox or width/height attributes to get dimensions.
3166−fn read_svg_dimensions(text: &str) -> Option<(u32, u32)> {
3167− // Try viewBox first: viewBox="minX minY width height"
3168− if let Some(vb_start) = text.find("viewBox=\"") {
3169− let rest = &text[vb_start + 9..];
3170− if let Some(end) = rest.find('"') {
3171− let parts: Vec<&str> = rest[..end].split_whitespace().collect();
3172− if parts.len() == 4
3173− && let (Ok(w), Ok(h)) = (parts[2].parse::<f64>(), parts[3].parse::<f64>())
3174− && w > 0.0
3175− && h > 0.0
3176− {
3177− return Some((w.round() as u32, h.round() as u32));
3178− }
3179− }
3180− }
3181− // Fall back to width/height attributes on <svg>
3182− let svg_tag = text.find("<svg")?;
3183− let tag_end = text[svg_tag..].find('>')? + svg_tag;
3184− let tag = &text[svg_tag..tag_end];
3185− let w = extract_svg_attr(tag, "width")?;
3186− let h = extract_svg_attr(tag, "height")?;
3187− Some((w, h))
3188−}
3189−
3190−fn extract_svg_attr(tag: &str, attr: &str) -> Option<u32> {
3191− let needle = format!("{}=\"", attr);
3192− let start = tag.find(&needle)? + needle.len();
3193− let rest = &tag[start..];
3194− let end = rest.find('"')?;
3195− let val = rest[..end].trim_end_matches("px");
3196− val.parse::<f64>().ok().map(|v| v.round() as u32)
3197−}
3198−
3199−/// Parse AVIF (ISOBMFF) container to find ispe box with image dimensions.
3200−fn read_avif_dimensions(data: &[u8]) -> Option<(u32, u32)> {
3201− // Walk ISOBMFF boxes looking for "ispe" (image spatial extents)
3202− let mut i = 0;
3203− while i + 8 <= data.len() {
3204− let box_size =
3205− u32::from_be_bytes([data[i], data[i + 1], data[i + 2], data[i + 3]]) as usize;
3206− let box_type = &data[i + 4..i + 8];
3207− if box_size < 8 {
3208− break;
3209− }
3210− let box_end = (i + box_size).min(data.len());
3211− // ispe box: 4 bytes version/flags + 4 bytes width + 4 bytes height
3212− if box_type == b"ispe" && box_end >= i + 20 {
3213− let w = u32::from_be_bytes([data[i + 12], data[i + 13], data[i + 14], data[i + 15]]);
3214− let h = u32::from_be_bytes([data[i + 16], data[i + 17], data[i + 18], data[i + 19]]);
3215− return Some((w, h));
3216− }
3217− // Recurse into container boxes (meta, iprp, ipco)
3218− if matches!(
3219− box_type,
3220− b"meta" | b"iprp" | b"ipco" | b"moov" | b"trak" | b"mdia"
3221− ) {
3222− let header_size = if box_type == b"meta" { 12 } else { 8 };
3223− if i + header_size < box_end
3224− && let Some(dims) = read_avif_dimensions(&data[i + header_size..box_end])
3225− {
3226− return Some(dims);
3227− }
3228− }
3229− i = box_end;
3230− }
3231− None
3232−}
3233−
32342338fn html_escape(s: &str) -> String {
32352339 s.replace('&', "&")
32362340 .replace('<', "<")
@@ -3346,43 +2450,30 @@ fn vlq_encode(value: i64, out: &mut String) {
33462450 }
33472451}
33482452
3349−
3350−/// Does the tree contain the table element `name` (e.g. `"main"`)?
3351−fn has_tag(nodes: &[Node], name: &str) -> bool {
3352− nodes.iter().any(|node| match node {
3353− Node::Element(elem) => elem.kind.is_tag(name) || has_tag(&elem.children, name),
3354− _ => false,
3355− })
3356−}
3357−
3358−/// Collect unique external domains from generated HTML for DNS prefetch hints.
3359−fn collect_dns_prefetch(html: &str, dev: bool) -> String {
3360− let mut domains = Vec::new();
3361− let mut rest = html;
3362− while let Some(pos) = rest.find("https://") {
3363− let start = pos + 8; // skip "https://"
3364− rest = &rest[start..];
3365− let end = rest
3366− .find(['/', '"', '\'', ' ', '>', ')'])
3367− .unwrap_or(rest.len());
3368− let domain = &rest[..end];
3369− if !domain.is_empty() && domain.contains('.') && !domains.contains(&domain.to_string()) {
3370− domains.push(domain.to_string());
3371− }
2453+#[cfg(test)]
2454+mod tests {
2455+ use super::*;
2456+
2457+ #[test]
2458+ fn a_name_is_a_stable_hash_of_the_style() {
2459+ // The same in every build and on every platform
2460+ assert_eq!(stable_hash(""), 0xf52a_15e9_a9b5_e89b);
2461+ assert_eq!(hash_digits(35, 3), "z00");
2462+ assert_eq!(hash_digits(u64::MAX, 13), "fsgs46211e5w3");
2463+ }
2464+
2465+ #[test]
2466+ fn a_name_taken_in_the_file_takes_more_digits() {
2467+ // These two styles' hashes end in the same 7 digits
2468+ let mut styles = StyleCollector::new();
2469+ let first = styles.get_class("width:129555px;".into(), Vec::new(), String::new());
2470+ let second = styles.get_class("width:170577px;".into(), Vec::new(), String::new());
2471+ let (first, second) = (first.unwrap(), second.unwrap());
2472+ assert_eq!(first.len(), 3 + CLASS_DIGITS, "{first}");
2473+ assert_eq!(second.len(), 3 + CLASS_DIGITS + 1, "{second}");
2474+ assert!(second.starts_with(&first), "{first} {second}");
2475+ // The same style gets the name it got before
2476+ let again = styles.get_class("width:170577px;".into(), Vec::new(), String::new());
2477+ assert_eq!(again.as_deref(), Some(second.as_str()));
33722478 }
3373− let mut out = String::new();
3374− for domain in &domains {
3375− if dev {
3376− out.push_str(&format!(
3377− "<link rel=\"dns-prefetch\" href=\"//{}\">\n",
3378− domain
3379− ));
3380− } else {
3381− out.push_str(&format!(
3382− "<link rel=\"dns-prefetch\" href=\"//{}\">",
3383− domain
3384− ));
3385− }
3386− }
3387− out
33882479}