border-block-width
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2021.
The border-block-width CSS property defines the width of the logical block borders of an element, which maps to a physical border width depending on the element's writing mode, directionality, and text orientation. It corresponds to the border-top-width and border-bottom-width, or border-left-width, and border-right-width property depending on the values defined for writing-mode, direction, and text-orientation.
Try it
border-block-width: thick;
writing-mode: horizontal-tb;
border-block-width: thick;
writing-mode: vertical-rl;
border-block-width: 4px;
writing-mode: horizontal-tb;
direction: rtl;
<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;
unicode-bidi: bidi-override;
}
The border width in the other dimension can be set with border-inline-width, which sets border-inline-start-width, and border-inline-end-width.
Syntax
/* <'border-width'> values */
border-block-width: 5px;
border-block-width: thick;
/* Global values */
border-block-width: inherit;
border-block-width: initial;
border-block-width: revert;
border-block-width: revert-layer;
border-block-width: unset;
Values
<'border-width'>-
The width of the border. See
border-width.
Formal definition
| Initial value | medium |
|---|---|
| Applies to | all elements |
| Inherited | no |
| Percentages | logical-width of containing block |
| Computed value | absolute length; 0 if the border style is none or hidden |
| Animation type | by computed value type |
Formal syntax
border-block-width =
<'border-top-width'> {1,2}
<border-top-width> =
<line-width>
<line-width> =
<length [0,∞]> |
thin |
medium |
thick
Examples
Border width with vertical text
HTML
<div>
<p class="exampleText">Example text</p>
</div>
CSS
div {
background-color: yellow;
width: 120px;
height: 120px;
}
.exampleText {
writing-mode: vertical-lr;
border: 1px solid blue;
border-block-width: 5px;
}
Results
Specifications
| Specification |
|---|
| CSS Logical Properties and Values Level 1 # propdef-border-block-width |
Browser compatibility
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See also
- CSS Logical Properties and Values
- This property maps to one of the physical border properties:
border-top-width,border-right-width,border-bottom-width, andborder-left-width writing-mode,direction,text-orientation