CSS baseline-source Property Reference

The CSS baseline-source property is a standard property in CSS Inline. Review its formal syntax, computed behavior, and practical declarations.

Updated 2026-08-12

baseline-source overview

The CSS baseline-source property is a standard property in CSS Inline. 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

baseline-source formal syntax

Field	Value
Formal syntax	auto \| first \| last
Initial value	auto
Applies to	inlineLevelBoxes
Inherited	No
Percentages	no
Computed value	asSpecified
Animation type	discrete
Media	visual
Specification group	CSS Inline
Status	Standard

Practical examples

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

baseline-source live example

CSS

.reset-example {
  baseline-source: initial;
}

.inherit-example {
  baseline-source: inherit;
}

@supports (baseline-source: initial) {
  .supported {
    baseline-source: initial;
  }
}