border-bottom

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

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

Try it

As with all shorthand properties, border-bottom always sets the values of all of the properties that it can set, even if they are not specified. It sets those that are not specified to their default values. Consider the following code:

css

border-bottom-style: dotted;
border-bottom: thick green;

It is actually the same as this one:

css

border-bottom-style: dotted;
border-bottom: none thick green;

The value of border-bottom-style given before border-bottom is ignored. Since the default value of border-bottom-style is none, not specifying the border-style part results in no border.

Constituent properties

This property is a shorthand for the following CSS properties:

Syntax

css

border-bottom: 1px;
border-bottom: 2px dotted;
border-bottom: medium dashed blue;

/* Global values */
border-bottom: inherit;
border-bottom: initial;
border-bottom: revert;
border-bottom: revert-layer;
border-bottom: unset;

The three values of the shorthand property can be specified in any order, and one or two of them may be omitted.

Values

<br-width>: See border-bottom-width.
<br-style>: See border-bottom-style.
<color>: See border-bottom-color.

Formal definition

Initial value	as each of the properties of the shorthand: `border-bottom-width`: `medium` `border-bottom-style`: `none` `border-bottom-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-bottom-width`: the absolute length or `0` if `border-bottom-style` is `none` or `hidden` `border-bottom-style`: as specified `border-bottom-color`: computed color
Animation type	as each of the properties of the shorthand: `border-bottom-color`: a CSS data type are interpolated on each of their red, green, blue components, each handled as a real, floating-point number. Note that interpolation of colors happens in the alpha-premultiplied sRGBA color space to prevent unexpected grey colors to appear.">color `border-bottom-style`: discrete `border-bottom-width`: a CSS data type are interpolated as real, floating-point numbers.">length

Formal syntax

border-bottom = 
  <line-width>  ||
  <line-style>  ||
  <color>       

<line-width> = 
  <length [0,∞]>  |
  thin            |
  medium          |
  thick           

<line-style> = 
  none    |
  hidden  |
  dotted  |
  dashed  |
  solid   |
  double  |
  groove  |
  ridge   |
  inset   |
  outset

Examples

Applying a bottom border

HTML

html

<div>This box has a border on the bottom side.</div>

CSS

css

div {
  border-bottom: 4px dashed blue;
  background-color: gold;
  height: 100px;
  width: 100px;
  font-weight: bold;
  text-align: center;
}

Results

Specifications

Specification
CSS Backgrounds and Borders Module Level 3 # border-shorthands

Browser compatibility

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