Web/CSS/border

The border shorthand CSS property sets an element's border. It sets the values of border-width, border-style, and border-color.

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Constituent properties

This property is a shorthand for the following CSS properties:

Syntax

/* style */
border: solid;

/* width | style */
border: 2px dotted;

/* style | color */
border: outset #f33;

/* width | style | color */
border: medium dashed green;

/* Global values */
border: inherit;
border: initial;
border: unset;

The border property may be specified using one, two, or three of the values listed below. The order of the values does not matter.

Note: The border will be invisible if its style is not defined. This is because the style defaults to none.

Values

<line-width>: Sets the thickness of the border. Defaults to medium if absent. See border-width.
<line-style>: Sets the style of the border. Defaults to none if absent. See border-style.
<color>: Sets the color of the border. Defaults to currentcolor if absent. See border-color.

Description

As with all shorthand properties, any omitted sub-values will be set to their initial value. Importantly, border cannot be used to specify a custom value for border-image, but instead sets it to its initial value, i.e., none.

The border shorthand is especially useful when you want all four borders to be the same. To make them different from each other, however, you can use the longhand border-width, border-style, and border-color properties, which accept different values for each side. Alternatively, you can target one border at a time with the physical (e.g., border-top ) and logical (e.g., border-block-start) border properties.

Borders vs. outlines

Borders and outlines are very similar. However, outlines differ from borders in the following ways:

Outlines never take up space, as they are drawn outside of an element's content.
According to the spec, outlines don't have to be rectangular, although they usually are.

Formal definition

Initial value	as each of the properties of the shorthand: `border-width`: as each of the properties of the shorthand: `border-top-width`: `medium` `border-right-width`: `medium` `border-bottom-width`: `medium` `border-left-width`: `medium` `border-style`: as each of the properties of the shorthand: `border-top-style`: `none` `border-right-style`: `none` `border-bottom-style`: `none` `border-left-style`: `none` `border-color`: as each of the properties of the shorthand: `border-top-color`: `currentcolor` `border-right-color`: `currentcolor` `border-bottom-color`: `currentcolor` `border-left-color`: `currentcolor`
Applies to	all elements. It also applies to `::first-letter`.
Inherited	no
Computed value	as each of the properties of the shorthand: `border-width`: as each of the properties of the shorthand: `border-bottom-width`: the absolute length or `0` if `border-bottom-style` is `none` or `hidden` `border-left-width`: the absolute length or `0` if `border-left-style` is `none` or `hidden` `border-right-width`: the absolute length or `0` if `border-right-style` is `none` or `hidden` `border-top-width`: the absolute length or `0` if `border-top-style` is `none` or `hidden` `border-style`: as each of the properties of the shorthand: `border-bottom-style`: as specified `border-left-style`: as specified `border-right-style`: as specified `border-top-style`: as specified `border-color`: as each of the properties of the shorthand: `border-bottom-color`: computed color `border-left-color`: computed color `border-right-color`: computed color `border-top-color`: computed color
Animation type	as each of the properties of the shorthand: `border-color`: as each of the properties of the shorthand: `border-bottom-color`: a color `border-left-color`: a color `border-right-color`: a color `border-top-color`: a color `border-style`: discrete `border-width`: as each of the properties of the shorthand: `border-bottom-width`: a length `border-left-width`: a length `border-right-width`: a length `border-top-width`: a length

Formal syntax

<line-width> || <line-style> || <color>where <line-width> = <length> | thin | medium | thick<line-style> = none | hidden | dotted | dashed | solid | double | groove | ridge | inset | outset<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 pink outset border

HTML

<div>I have a border, an outline, AND a box shadow! Amazing, isn't it?</div>

CSS

div {
  border: 0.5rem outset pink;
  outline: 0.5rem solid khaki;
  box-shadow: 0 0 0 2rem skyblue;
  border-radius: 12px;
  font: bold 1rem sans-serif;
  margin: 2rem;
  padding: 1rem;
  outline-offset: 0.5rem;
}

Result

Specifications

Specification	Status	Comment
CSS Backgrounds and Borders Module Level 3The definition of 'border' in that specification.	Candidate Recommendation	Removes specific support for `transparent`, as it is now a valid `<color>`; this has no practical impact. Though it cannot be set to a custom value using the shorthand, `border` now resets `border-image` to its initial value (`none`).
CSS Level 2 (Revision 1)The definition of 'border' in that specification.	Recommendation	Accepts the `inherit` keyword. Also accepts `transparent` as a valid color.
CSS Level 1The definition of 'border' in that specification.	Recommendation	Initial definition.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`border`	Chrome Full support 1	Edge Full support 12	Firefox Full support 1	IE Full support 4	Opera Full support 3.5	Safari Full support 1	WebView Android Full support ≤37	Chrome Android Full support 18	Firefox Android Full support 4	Opera Android Full support 14	Safari iOS Full support 1	Samsung Internet Android Full support 1.0

Legend

Full support: Full support

border by Mozilla Contributors is licensed under CC-BY-SA 2.5.