outline-color - CSS: Cascading Style Sheets 编辑

The outline-color CSS property sets the color of an element's outline.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

Syntax

/* <color> values */
outline-color: #f92525;
outline-color: rgb(30,222,121);
outline-color: blue;

/* Keyword value */
outline-color: invert;

/* Global values */
outline-color: inherit;
outline-color: initial;
outline-color: unset;

The outline-color property is specified as any one of the values listed below.

Values

<color>

The color of the outline, specified as a <color>.

invert

To ensure the outline is visible, performs a color inversion of the background. Note that browsers are not required to support this value; if they don't, this keyword is considered invalid.

Description

An outline is a line that is drawn around an element, outside the border. Unlike the element's border, the outline is drawn outside the element's frame, and may overlap other content. The border, on the other hand, will actually alter the page's layout to ensure that it fits without overlapping anything else (unless you explicitly set it to overlap).

It is often more convenient to use the shorthand property outline when defining the appearance of an outline.

Accessibility concerns

Custom focus styles commonly involve making adjustments to the outline property. If the color of the outline is adjusted, it is important to ensure that the contrast ratio between it and the background the outline is placed over is high enough that people experiencing low vision conditions will be able to perceive it.

Color contrast ratio is determined by comparing the luminosity of the text and background color values. In order to meet current Web Content Accessibility Guidelines (WCAG), a ratio of 4.5:1 is required for text content and 3:1 for larger text such as headings. Large text is defined as 18.66px and bold or larger, or 24px or larger.

• WebAIM: Color Contrast Checker
• MDN Understanding WCAG, Guideline 1.4 explanations
• Understanding Success Criterion 1.4.3 | W3C Understanding WCAG 2.0

Formal definition

Initial value	invert, for browsers supporting it, currentColor for the other
Applies to	all elements
Inherited	no
Computed value	For the keyword invert, the computed value is invert. For the color value, if the value is translucent, the computed value will be the rgba() corresponding one. If it isn't, it will be the rgb() corresponding one. The transparent keyword maps to rgba(0,0,0,0).
Animation type	a color

Formal syntax

<color> | invert
where 
<color> = <rgb()> | <rgba()> | <hsl()> | <hsla()> | <hex-color> | <named-color> | currentcolor | <deprecated-system-color>
where 
<rgb()> = rgb( <percentage>{3} [ / <alpha-value> ]? ) | rgb( <number>{3} [ / <alpha-value> ]? ) | rgb( <percentage>#{3} , <alpha-value>? ) | rgb( <number>#{3} , <alpha-value>? )
<rgba()> = rgba( <percentage>{3} [ / <alpha-value> ]? ) | rgba( <number>{3} [ / <alpha-value> ]? ) | rgba( <percentage>#{3} , <alpha-value>? ) | rgba( <number>#{3} , <alpha-value>? )
<hsl()> = hsl( <hue> <percentage> <percentage> [ / <alpha-value> ]? ) | hsl( <hue>, <percentage>, <percentage>, <alpha-value>? )
<hsla()> = hsla( <hue> <percentage> <percentage> [ / <alpha-value> ]? ) | hsla( <hue>, <percentage>, <percentage>, <alpha-value>? )
where 
<alpha-value> = <number> | <percentage>
<hue> = <number> | <angle>

Examples

Setting a solid blue outline

HTML

<p>My outline is blue, as you can see.</p>

CSS

p {
  outline: 2px solid;      /* Set the outline width and style */
  outline-color: #0000FF;  /* Make the outline blue */
  margin: 5px;
}

Result

Specifications

Specification	Status	Comment
CSS Basic User Interface Module Level 3 The definition of 'outline-color' in that specification.	Recommendation	No change.
CSS Level 2 (Revision 1) The definition of 'outline-color' in that specification.	Recommendation	Initial definition.

Browser compatibility

BCD tables only load in the browser

See also

• outline
• outline-color
• outline-style
• outline-width
• The <color> data type
• Other color-related properties: color, background-color, border-color, text-decoration-color, text-emphasis-color, text-shadow, caret-color, and column-rule-color
• Applying color to HTML elements using CSS