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`border-bottom` CSS property

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.

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

Try it

border-bottom: solid;

border-bottom: dashed red;

border-bottom: 1rem solid;

border-bottom: thick double #32a1ce;

border-bottom: 4mm ridge rgb(211 220 50 / 0.6);

<section class="default-example" id="default-example">
  <div class="transition-all" id="example-element">
    This is a box with a border around it.
  </div>
</section>

#example-element {
  background-color: #eeeeee;
  color: darkmagenta;
  padding: 0.75em;
  width: 80%;
  height: 100px;
}

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.

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.

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>`, snapped as a line width `border-bottom-style`: as specified `border-bottom-color`: computed color
Animation type	as each of the properties of the shorthand: `border-bottom-width`: a length `border-bottom-style`: discrete `border-bottom-color`: a color

Formal syntax

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

<line-width> = 
  <length [0,∞]>  |
  hairline        |
  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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This page was last modified on Aug 27, 2026 by MDN contributors.

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