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 value as each of the properties of the shorthand:
Applies to all elements
Inherited no
Media visual, interactive
Computed value as 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 type as each of the properties of the shorthand:
Canonical order order 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; }


Browser compatibility

Feature Chrome Edge Firefox Internet Explorer Opera Safari
Basic support 1 Yes


1 —? -moz-

8 7 1.2
Feature Android webview Chrome for Android Edge mobile Firefox for Android IE mobile Opera Android iOS Safari
Basic support 1 ? Yes 4 8 7 3.1

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

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.