border-block-start - CSS | MDN (original) (raw)

Try it

border-block-start: solid;
writing-mode: horizontal-tb;

border-block-start: dashed red;
writing-mode: vertical-rl;

border-block-start: 1rem solid;
writing-mode: horizontal-tb;

border-block-start: thick double #32a1ce;
writing-mode: vertical-lr;

<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;
  unicode-bidi: bidi-override;
}

Constituent properties

This property is a shorthand for the following CSS properties:

Syntax

border-block-start: 1px;
border-block-start: 2px dotted;
border-block-start: medium dashed blue;

/* Global values */
border-block-start: inherit;
border-block-start: initial;
border-block-start: revert;
border-block-start: revert-layer;
border-block-start: unset;

border-block-start can be used to set the values for one or more of border-block-start-width, border-block-start-style, and border-block-start-color. The physical border to which it maps depends on the element's writing mode, directionality, and text orientation. It corresponds to the border-top, border-right, border-bottom, or border-left property depending on the values defined for writing-mode, direction, and text-orientation.

Related properties are border-block-end, border-inline-start, and border-inline-end, which define the other borders of the element.

Values

The border-block-start is specified with one or more of the following, in any order:

<'border-width'>

The width of the border. See border-width.

<'border-style'>

The line style of the border. See border-style.

The color of the border.

Formal definition

Initial value	as each of the properties of the shorthand:border-width: as each of the properties of the shorthand:border-top-width: mediumborder-right-width: mediumborder-bottom-width: mediumborder-left-width: mediumborder-style: as each of the properties of the shorthand:border-top-style: noneborder-right-style: noneborder-bottom-style: noneborder-left-style: nonecolor: canvastext
Applies to	all elements
Inherited	no
Computed value	as each of the properties of the shorthand:border-width: as each of the properties of the shorthand:border-bottom-width: the absolute length or 0 if border-bottom-style is none or hiddenborder-left-width: the absolute length or 0 if border-left-style is none or hiddenborder-right-width: the absolute length or 0 if border-right-style is none or hiddenborder-top-width: the absolute length or 0 if border-top-style is none or hiddenborder-style: as each of the properties of the shorthand:border-bottom-style: as specifiedborder-left-style: as specifiedborder-right-style: as specifiedborder-top-style: as specifiedborder-block-start-color: computed color
Animation type	as each of the properties of the shorthand:border-block-start-color: by computed value typeborder-block-start-style: discreteborder-block-start-width: by computed value type

Formal syntax

border-block-start =
||
||

=
<length [0,∞]> |
thin |
medium |
thick

Examples

Border 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-rl;
  border-block-start: 5px dashed blue;
}

Specifications

Specification
CSS Logical Properties and Values Level 1 # border-shorthands