The border-top-width
CSS property sets the width of the top border of an element.
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Syntax
/* Keyword values */
border-top-width: thin;
border-top-width: medium;
border-top-width: thick;
/* <length> values */
border-top-width: 10em;
border-top-width: 3vmax;
border-top-width: 6px;
/* Global keywords */
border-top-width: inherit;
border-top-width: initial;
border-top-width: unset;
Values
<line-width>
- Defines the width of the border, either as an explicit nonnegative
<length>
or a keyword. If it's a keyword, it must be one of the following values:thin
A thin border medium
A medium border thick
A thick border Note: Because the specification doesn't define the exact thickness denoted by each keyword, the precise result when using one of them is implementation-specific. Nevertheless, they always follow the pattern
thin ≤ medium ≤ thick
, and the values are constant within a single document.
Formal definition
Initial value | medium |
---|---|
Applies to | all elements. It also applies to ::first-letter . |
Inherited | no |
Computed value | the absolute length or 0 if border-top-style is none or hidden |
Animation type | a length |
Formal syntax
<line-width>where <line-width> = <length> | thin | medium | thick
Examples
HTML
<div>Element 1</div>
<div>Element 2</div>
CSS
div {
border: 1px solid red;
margin: 1em 0;
}
div:nth-child(1) {
border-top-width: thick;
}
div:nth-child(2) {
border-top-width: 2em;
}
Result
Specifications
Specification | Status | Comment |
---|---|---|
CSS Backgrounds and Borders Module Level 3 The definition of 'border-top-width' in that specification. |
Candidate Recommendation | No significant change. |
CSS Level 2 (Revision 1) The definition of 'border-top-width' in that specification. |
Recommendation | No significant change. |
CSS Level 1 The definition of 'border-top-width' in that specification. |
Recommendation | Initial definition. |
Browser compatibility
BCD tables only load in the browser
See also
- The other border-width-related CSS properties:
border-left-width
,border-right-width
,border-bottom-width
, andborder-width
. - The other border-top-related CSS properties:
border
,border-top
,border-top-style
, andborder-top-color
.