CSS outline Property Reference

The CSS outline property is a standard property in CSS Basic User Interface. Review its formal syntax, computed behavior, and practical declarations.

Updated 2026-08-12

outline overview

The CSS outline property is a standard property in CSS Basic User Interface. 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

outline formal syntax

Field	Value
Formal syntax	<'outline-width'> \|\| <'outline-style'> \|\| <'outline-color'>
Initial value	outline-width, outline-style, outline-color
Applies to	allElements
Inherited	No
Percentages	no
Computed value	outline-width, outline-style, outline-color
Animation type	outline-width, outline-style, outline-color
Media	visual, interactive
Specification group	CSS Basic User Interface
Status	Standard

Practical examples

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

outline live example

CSS

.reset-example {
  outline: initial;
}

.inherit-example {
  outline: inherit;
}

@supports (outline: initial) {
  .supported {
    outline: initial;
  }
}