border CSS property on arvau

MDN / border CSS property

The border shorthand CSS property sets an element’s border. It sets the values of , , and .

border: solid;

border: dashed red;

border: 1rem solid;

border: thick double #32a1ce;

border: 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

/* style */
border: solid;

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

/* style | color */
border: outset #ff3333;

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

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

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 .
- : Sets the style of the border. Defaults to none if absent. See .
- : Sets the color of the border. Defaults to currentColor if absent. See .

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 , 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 , , and properties, which accept different values for each side. Alternatively, you can target one border at a time with the physical (e.g., ) and logical (e.g., ) 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

Formal syntax

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;
}