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css property

`border-left-width` CSS property

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The border-left-width CSS property sets the width of the left border of an element.

Interactive exampleOpen the canonical MDN source to run this embedded demo.
border-left-width: thick;

border-left-width: 2em;

border-left-width: 4px;

border-left-width: 2ex;

border-left-width: 0;

<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: palegreen;
  color: black;
  border: 0 solid crimson;
  padding: 0.75em;
  width: 80%;
  height: 100px;
}

Syntax

/* Keyword values */
border-left-width: thin;
border-left-width: medium;
border-left-width: thick;

/* <length> values */
border-left-width: 10em;
border-left-width: 3vmax;
border-left-width: 6px;

/* Global keywords */
border-left-width: inherit;
border-left-width: initial;
border-left-width: revert;
border-left-width: revert-layer;
border-left-width: unset;

Values

  • &lt;line-width&gt;
    • : Defines the width of the border, either as an explicit non-negative &lt;length&gt; or the keywords: thin, medium, or thick. The default is medium.

Formal definition

Formal syntax

Examples

Comparing border widths

HTML

<div>Element 1</div>
<div>Element 2</div>

CSS

div {
  border: 1px solid red;
  margin: 1em 0;
}

div:nth-child(1) {
  border-left-width: thick;
}
div:nth-child(2) {
  border-left-width: 2em;
}

Result

Interactive exampleOpen the canonical MDN source to run this embedded demo.

Specifications

SpecificationsStandards references are available on the canonical MDN page.

Browser compatibility

Browser compatibilityCompatibility data is available on the canonical MDN page.

See also