Skins {#skin}

Core Skins

MediaWiki bundles five skins:

Vector 2022: The default skin. A modernised version of the Vector skin, with improved accessibility and mobile support. Introduced in the 1.36 release (2021), it has been the default in MediaWiki since 1.37 (2022).
Vector (legacy): Introduced in the 1.16 release (2010), it had been the default skin since MediaWiki 1.17 (2011) until the introduction of Vector 2022. It was designed to be more user-friendly and visually appealing than the previous default, MonoBook.
MinervaNeue: A mobile-optimized skin, introduced in the 1.19 release (2012). It is designed for mobile devices, but can also be used on desktop.
Timeless: A responsive skin for different screen sizes, equally focussed on reading and editing interfaces, introduced in the 1.31 release (2018).
MonoBook: Named after the black-and-white photo of a book in the page background. Introduced in the 1.3 release (2004), it had been the default skin since then, before being replaced by Vector.

Custom CSS/JS

It is possible to customise the site CSS and JavaScript without editing any server-side source files. This is done by editing some pages on the wiki:

MediaWiki:Common.css for skin-independent CSS
MediaWiki:Common.js for skin-independent JavaScript
MediaWiki:Vector.css, MediaWiki:Minerva.css, etc. for skin-dependent CSS
MediaWiki:Vector.js, MediaWiki:Minerva.js, etc. for skin-dependent JavaScript

These can also be customised on a per-user basis, by editing User:<name>/vector.css, User:<name>/vector.js, etc.

Custom skins

Several custom skins are available as of 2019. List of all skins is available at MediaWiki.org.

Installing a skin requires adding its files in a subdirectory under skins/ and adding an appropriate wfLoadSkin line to LocalSettings.php, similarly to how extensions are installed.

You can then make that skin the default by adding:

php

$wgDefaultSkin = '<name>';

Or disable it entirely by removing the wfLoadSkin line. (User settings will not be lost if it's reenabled later.)

See https://www.mediawiki.org/wiki/Special:MyLanguage/Manual:Skinning for more information on writing new skins.