CSS border-inline-start-width Property Reference

The CSS border-inline-start-width property is a standard property in CSS Logical Properties and Values. Review its formal syntax, computed behavior, and practical declarations.

Updated 2026-08-12

border-inline-start-width overview

The CSS border-inline-start-width property is a standard property in CSS Logical Properties and Values. Review its formal syntax, computed behavior, and practical declarations.

The property is not inherited by default. Use an explicit global keyword when inheritance is intended.

Syntax and formal definition

border-inline-start-width formal syntax

Field	Value
Formal syntax	<'border-top-width'>
Initial value	medium
Applies to	allElements
Inherited	No
Percentages	no
Computed value	absoluteLengthSnappedAsLineWidth
Animation type	byComputedValueType
Media	visual
Specification group	CSS Logical Properties and Values
Status	Standard

Practical examples

These declarations demonstrate valid ways to set border-inline-start-width. The initial and inherit global keywords remain available even when a property-specific value is preferable.

border-inline-start-width live example

CSS

.reset-example {
  border-inline-start-width: initial;
}

.inherit-example {
  border-inline-start-width: inherit;
}

@supports (border-inline-start-width: initial) {
  .supported {
    border-inline-start-width: initial;
  }
}