Through community CSS and JavaScript, local administrators can affect the way all visitors—logged in or not—see their wikis on desktop and tablets.

Local customization offers great challenge and satisfaction to many editors, so we at Fandom encourage you to try your hand at it. But there are two important things to keep in mind as you do:

  • Use the Theme designer first, before attempting any CSS customization - it'll likely make your life a lot easier.
  • There are some limits as to what and how you can customize things, as both our customization policy and Terms of Use explain in greater detail.



Editing a light-themed community's CSS.

To customize your community's CSS, simply edit MediaWiki:Wikia.css. You can also access this page from the Admin Dashboard via the CSS link.

The Community Central Technical Updates board contains periodic updates about changes that might affect your customizations. Another board, Designing Your Wiki, is a great place to get help from other users if needed. This webinar and this PDF are also great resources to learn more about custom community CSS.

CSS pages

MediaWiki:Common.css and MediaWiki:Wikia.css are both used for Fandom's layout, but they may be consolidated in the future.

On all wikis created after July 2014
MediaWiki:Common.css is loaded. The contents will be applied before MediaWiki:Wikia.css. For most communities this doesn't matter, but if you use both pages and @import rules (like for importing custom fonts), then these rules must be added at the top of MediaWiki:Common.css to function.
On most wikis created before July 2014
MediaWiki:Common.css is not loaded. If you want to use MediaWiki:Common.css, ask Fandom Staff to enable this. If you do so, make sure to clean up any old CSS in MediaWiki:Common.css beforehand, otherwise, it may cause unexpected effects.


With the exception of imported scripts from the Fandom Developers Wiki through ImportJS, you cannot include community JS until you ask Fandom to turn it on for you. After it's enabled, you'll probably want to edit the main JS page, MediaWiki:Common.js, where you can add freeform JS as opposed to only imports. Whatever JS is there will be loaded for all visitors to your community, whether they're logged in or not. So be aware of the following:

  • For security reasons, edits to community JS must go through an approval process.
    • Using ImportJS bypasses the need for the review process.
  • JS errors can break basic functionality in your community. Please be careful to avoid introducing errors.
  • Please do not include JS that you do not understand, nor import from sources that you do not fully trust. Additionally, do not import JS from personal JS pages, or from insecure pages.
  • As with the CSS pages, both Common.js and Wikia.js affect the whole wiki, but they may be consolidated in the future.

Some technicalities

Changes you make to either CSS or JS are usually not immediately seen upon publication. This is because of a concept called "caching". If you're in the middle of a lengthy period of editing your CSS and JS, you may have to frequently bypass your cache to see your changes.

Also, Fandom's load order—the priority given to each of the various pages used to customize your wiki—is crucial for administrators to understand. A common reason that some customizations aren't seen is because a later-loading page effectively cancels a declaration made on an earlier-loading page.

See also

Further help and feedback

Community content is available under CC-BY-SA unless otherwise noted.