The outline CSS property is a shorthand property for setting one or more of the individual outline properties outline-style, outline-width, and outline-color in a single declaration.

/* width | style | color */
outline: 1px solid white;

/* Global values */
outline: inherit;
outline: initial;
outline: unset;

Outlines differ from borders in the following ways:

  • Outlines never take up space, as they are drawn outside of an element's content.
  • Outlines may be non-rectangular. They are rectangular in Gecko/Firefox, but Opera, for example, draws a non-rectangular shape around a construct like this:
Initial valueas each of the properties of the shorthand:
Applies toall elements
Mediavisual, interactive
Computed valueas each of the properties of the shorthand:
  • outline-color: For the keyword invert, the computed value is invert. For the color value, if the value is translucent, the computed value will be the rgba() corresponding one. If it isn't, it will be the rgb() corresponding one. The transparent keyword maps to rgba(0,0,0,0).
  • outline-width: an absolute length; if the keyword none is specified, the computed value is 0
  • outline-style: as specified
Animation typeas each of the properties of the shorthand:
Canonical orderorder of appearance in the formal grammar of the values


The outline property is specified as one, two, or three values from the list below. The order of the values does not matter.


Sets the thickness of the outline.
Sets the style of the outline.
Sets the color of the outline. Since Gecko 1.9 (Firefox 3), the value of the element's color property (foreground color) is used as the default.

Formal syntax

[ <'outline-color'> || <'outline-style'> || <'outline-width'> ]


outline: solid; | outline: dashed red; | outline: dotted 1px; | outline: ridge thick violet; | outline: custom 5px;

/* Two identical declarations */

:link:hover { outline: 1px solid #000; }
:link:hover { outline: solid black 1px; }


Specification Status Comment
CSS Basic User Interface Module Level 3
The definition of 'outline' in that specification.
Candidate Recommendation No change.
CSS Level 2 (Revision 1)
The definition of 'outline' in that specification.
Recommendation Initial definition.

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 1.0 (Yes) 1.5 (1.8)[1] 8.0 7.0 1.2 (125)
Feature Android Edge Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support 1.0 (Yes) 1.0 (1.8) [1] 8.0 6.0 3.1

[1] In browsers previous to Gecko 1.8 (Firefox 1.5) a similar effect can be achieved using Mozilla CSS Extension -moz-outline.

Firefox includes absolutely positioned elements inside the outline (bug 687311).

Document Tags and Contributors

 Last updated by: mfluehr,