border-block-start-style

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨January 2020⁩.

The border-block-start-style CSS property defines the style of the logical block start border of an element, which maps to a physical border style depending on the element's writing mode, directionality, and text orientation. It corresponds to the border-top-style, border-right-style, border-bottom-style, or border-left-style property depending on the values defined for writing-mode, direction, and text-orientation.

Try it

border-block-start-style: dotted; writing-mode: horizontal-tb;

border-block-start-style: dotted; writing-mode: vertical-rl;

border-block-start-style: groove; writing-mode: horizontal-tb;

border-block-start-style: dashed; 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: black; border: 0.75em solid; padding: 0.75em; width: 80%; height: 100px; unicode-bidi: bidi-override; }

Syntax

css

/* <'border-style'> values */ border-block-start-style: dashed; border-block-start-style: dotted; border-block-start-style: groove; /* Global values */ border-block-start-style: inherit; border-block-start-style: initial; border-block-start-style: revert; border-block-start-style: revert-layer; border-block-start-style: unset;

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

Values

<'border-style'>: The line style of the border. See border-style.

Formal definition

Initial value	`none`
Applies to	all elements
Inherited	no
Computed value	as specified
Animation type	discrete

Formal syntax

border-block-start-style = 
 <line-style> 

<line-style> = 
 none |
 hidden |
 dotted |
 dashed |
 solid |
 double |
 groove |
 ridge |
 inset |
 outset

Examples

Dashed border with vertical text

HTML

html

<div> <p class="exampleText">Example text</p> </div>

CSS

css

div { background-color: yellow; width: 120px; height: 120px; } .exampleText { writing-mode: vertical-lr; border: 5px solid blue; border-block-start-style: dashed; }

Results

Specifications

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

Browser compatibility

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This page was last modified on ⁨Nov 7, 2025⁩ by MDN contributors.

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