Non-standard
This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
The :-moz-system-metric(windows-default-theme)
CSS pseudo-class matches an element if the user is currently using one of the following themes in Windows: Luna, Royale, Zune, or Aero (i.e., Vista Basic, Vista Standard, or Aero Glass). This will exclude Windows Classic themes as well as third-party themes.
This selector is intended for use mainly by theme developers.
Note: Since Firefox 58, this pseudo-class is no longer available to web content — it is only available internally (e.g. to XUL / chrome code). See bug 1396066 for more details.
Example
HTML Content
<p id="defaultThemes"> This paragraph should have a green background with Luna/Royale/Zune/Aero Windows themes and red with other themes. </p> <p id="nonDefaultThemes"> This paragraph should have a green background with Windows Classic or third-party themes and red with other themes. </p> <p id="notSupported">Theme detection is not supported.</p>
CSS Content
#defaultThemes, #nonDefaultThemes { background-color: #FFA0A0; } #defaultThemes:-moz-system-metric(windows-default-theme) { background-color: #A0FFA0; } #nonDefaultThemes:not(-moz-system-metric(windows-default-theme)) { background-color: #A0FFA0; } #notSupported:-moz-system-metric(windows-default-theme), #notSupported:not(:-moz-system-metric(windows-default-theme)) { display: none; }
Specifications
Not part of any specification.
Browser compatibility
No compatibility data found. Please contribute data for "css.selectors.-moz-system-metric.windows-default-theme" (depth: 1) to the MDN compatibility data repository.