docs: document configuring the tab bar colors

docs/configuration.markdown

@@ -374,3 +374,56 @@ $ for scheme in *.sh ; do ; echo $scheme ; \
 
   <video width="80%" controls src="screenshots/wezterm-dynamic-colors.mp4" loop></video>
 
+### Tab Bar Colors
+
+The following options control the appearance of the tab bar:
+
+```toml
+[colors.tab_bar]
+# The color of the strip that goes along the top of the window
+background = "#0b0022"
+
+# The active tab is the one that has focus in the window
+[colors.tab_bar.active_tab]
+# The color of the background area for the tab
+bg_color = "#2b2042"
+# The color of the text for the tab
+fg_color = "#c0c0c0"
+
+# Specify whether you want "Half", "Normal" or "Bold" intensity for the
+# label shown for this tab.
+# The default is "Normal"
+intensity = "Normal"
+
+# Specify whether you want "None", "Single" or "Double" underline for
+# label shown for this tab.
+# The default is "None"
+underline = "None"
+
+# Specify whether you want the text to be italic (true) or not (false)
+# for this tab.  The default is false.
+italic = false
+
+# Specify whether you want the text to be rendered with strikethrough (true)
+# or not for this tab.  The default is false.
+strikethrough = false
+
+# Inactive tabs are the tabs that do not have focus
+[colors.tab_bar.inactive_tab]
+bg_color = "#1b1032"
+fg_color = "#808080"
+
+# The same options that were listed under the `active_tab` section above
+# can also be used for `inactive_tab`.
+
+# You can configure some alternate styling when the mouse pointer
+# moves over inactive tabs
+[colors.tab_bar.inactive_tab_hover]
+bg_color = "#3b3052"
+fg_color = "#909090"
+italic = true
+
+# The same options that were listed under the `active_tab` section above
+# can also be used for `inactive_tab_hover`.
+```
+