The `.Box` component can be used for something as simple as a rounded corner box, or more complex lists and forms. It includes optional modifiers for padding density and color themes.
## Box
A `.Box` is a container with a a white background, a light gray border, and rounded corners. By default there are no additional styles such as padding, these can be added as needed with utility classes. Other styles and layouts can be achieved with box elements and modifiers shown in the documentation below.
```html live
<divclass="Box">
This is a box.
</div>
```
## Box elements
Box elements include `Box-header`, `Box-body`, and `Box-footer`. These elements include borders and consistent padding. Optionally, you can include use `Box-title` which applies a bold font-weight the heading.
```html live
<divclass="Box">
<divclass="Box-header">
<h3class="Box-title">
Box title
</h3>
</div>
<divclass="Box-body">
Box body
</div>
<divclass="Box-footer">
Box footer
</div>
</div>
```
### Box row
Use `Box-row` to add rows with borders and maintain the same padding. Box rows have a lighter border to give contrast between the header and footer.
**Note:** Box rows have some reliance on markup structure in order to target the first and last rows, therefore using an unordered list is recommended. See [box row markup structure](#box-row-markup-structure) for more information.
```html live
<divclass="Box">
<ul>
<liclass="Box-row">
Box row one
</li>
<liclass="Box-row">
Box row two
</li>
<liclass="Box-row">
Box row three
</li>
<liclass="Box-row">
Box row four
</li>
</ul>
</div>
```
Rows can be used with or without `Box-header`, `Box-footer`, or `Box-body`.
```html live
<divclass="Box">
<divclass="Box-header">
Box header
</div>
<divclass="Box-body">
<strong>Box body</strong>
</div>
<ul>
<liclass="Box-row">
Box row one
</li>
<liclass="Box-row">
Box row two
</li>
<liclass="Box-row">
Box row three
</li>
<liclass="Box-row">
Box row four
</li>
</ul>
<divclass="Box-footer">
Box footer
</div>
</div>
```
### Box row markup structure
Box rows have some reliance on markup structure in order to target the first and last rows. Box rows are given a top border that is lighter in color than other box elements so the first row is targeted to apply a darker border color. An inner border-radius is applied to the first and last rows that that row corners don't poke outside the `Box`, this can be particularly noticeable when using a highlight on box rows.
Using an unordered list is recommended in order to target the first and last rows, however, if you need to use a `<div>` for your rows, you may want to place your rows inside a parent `<div>` so that the first and last rows are styled appropriately.
You can changed the padding density of the box component.
Use `Box--condensed` to apply a more condensed line-height and reduce the padding on the Y axis.
```html live
<divclass="Box Box--condensed">
<divclass="Box-header">
<h3class="Box-title">
Box title
</h3>
</div>
<divclass="Box-body">
Box body
</div>
<ul>
<liclass="Box-row">
Box row one
</li>
<liclass="Box-row">
Box row two
</li>
</ul>
<divclass="Box-footer">
Box footer
</div>
</div>
```
Use `Box--spacious` to increase padding and increase the title font size.
You may want to increase the overall font size to work with the larger padding, in this example the default body font size is increased to 16px using the `f4` typography utility.
```html live
<divclass="Box Box--spacious f4">
<divclass="Box-header">
<h3class="Box-title">
Box title
</h3>
</div>
<divclass="Box-body">
Box body
</div>
<ul>
<liclass="Box-row">
Box row one
</li>
<liclass="Box-row">
Box row two
</li>
</ul>
<divclass="Box-footer">
Box footer
</div>
</div>
```
## Blue box theme
Use `Box--blue` to style the box borders and box header in blue.
```html live
<divclass="Box Box--blue">
<divclass="Box-header">
Box header
</div>
<ul>
<liclass="Box-row">
Box row one
</li>
<liclass="Box-row">
Box row two
</li>
</ul>
<divclass="Box-footer">
Box footer
</div>
</div>
```
## Blue box header theme
Use `Box-header--blue` to add to change the header border and background to blue.
```html live
<divclass="Box">
<divclass="Box-header Box-header--blue">
<h3class="Box-title">Box with blue header</h3>
</div>
<divclass="Box-body">
Box body
</div>
</div>
```
## Box danger theme
Use `Box--danger` to apply a red border to the outside of the box. This theme is helpful for communicating destructive actions.
**Note:** `Box-danger` only works with either `Box-row`'s or `Box-body`.
```html live
<divclass="Box Box--danger">
<divclass="Box-row">
Row one
</div>
<divclass="Box-row">
Row two
</div>
</div>
```
`Box-danger` is often paired with a red heading. See the [subhead](./subhead) docs for more information.
You can change the background color for individual rows, or change the color on hover or navigation focus.
```html live
<divclass="Box">
<divclass="Box-row Box-row--gray">
.Box-row--gray
</div>
<divclass="Box-row Box-row--hover-gray">
.Box-row--hover-gray
</div>
<divclass="Box-row Box-row--yellow">
.Box-row--yellow
</div>
<divclass="Box-row Box-row--hover-blue">
.Box-row--hover-blue
</div>
<divclass="Box-row Box-row--blue">
.Box-row--blue
</div>
</div>
```
Use `Box-row--focus-gray` or `Box-row--focus-blue` when using along-side `navigation-focus` if you want to highlight rows when using keyboard commands.
Use .`Box-row-link` when you want a link to appear dark gray and blue on hover on desktop, and remain a blue link on mobile. This is useful to indicate links on mobile without having hover styles.
Use the `border-dashed` utility to apply a dashed border to a box.
```html live
<divclass="Box border-dashed p-2">
A box with a dashed border
</div>
```
## Boxes with flash alerts
Use `flash-full` for flash alert inside a box to remove the rounded corners. Place the flash alert above the `Box-body` and underneath the `Box-header`.
Flash alerts come in three different colors and can be used with icons and buttons, see the [alert documentation](./alerts) for more information.
Use `Box-btn-octicon` with `btn-octicon` when you want the icon to maintain the same padding as other box elements. This selector offsets margin to ensure it lines up on the left and right sides of the box so you may need to add padding neighboring elements.
It's common to want to float icons to the far left or right and stop the `Box-title`from wrapping underneath. To do this you'll need to create a media object with utilities. Add `clearfix` to the surrounding div (this could be the header, body, or rows), add `overflow-hidden` to the title (or other text element), and float the icons as desired.
<h3class="Box-title overflow-hidden pr-3">A very long title that wraps onto multiple lines without overlapping or wrapping underneath the icon to it's right</h3>
<pclass="overflow-hidden pl-3">A very long paragraph that wraps onto multiple lines without overlapping or wrapping underneath the icon to it's left</p>
</div>
</div>
```
## Box headers with counters
Use a counter with a background that works against the contrast of the box header. The default counter colors do not stand out well against the header background so we suggest using one of the following styles:
Use `Counter--gray` for a counter with a gray background and dark gray text.
```html live
<divclass="Box">
<divclass="Box-header">
<h3class="Box-title">
Box title
<spanclass="Counter Counter--gray">12</span>
</h3>
</div>
<divclass="Box-body">
Box body
</div>
</div>
```
Use `Counter--gray-dark` for a counter with a dark gray background and white text.
```html live
<divclass="Box">
<divclass="Box-header">
<h3class="Box-title">
Box title
<spanclass="Counter Counter--gray-dark">12</span>
</h3>
</div>
<divclass="Box-body">
Box body
</div>
</div>
```
## Form elements and buttons in boxes
To achieve different layouts when adding buttons or form elements to boxes we suggest you use utilities to achieve the layout you want. Here's some common examples:
Use [flexbox utilities](/utilities/flexbox) to center align items, and avoid using floats by using `flex-auto` to have the text fill the remaining space so that the button rests on the far right.
You can put forms in boxes. Often form submission buttons are aligned to the bottom right of the form which you can do with `text-right` instead of using floats.
When a box is all by itself centered on a page you can use [column widths](/objects/grid) to control the width of the box. If needed, break the mold a little and use [typography utilities](/utilities/typography) instead of the built in box title styles.
