Help:Global CSS and JS
From Tardis Wiki, the free Doctor Who reference
The following file tells you how you can change your personal CSS and JS. Many users do not utilise this function, and it is not necessary. However, if there is some feature you would like to ensure happens on every Wikia wiki, then you must change your global CSS and/or JS.
You can also change your personal CSS and/or JS on just this wiki. A change we recommend you make to your personal CSS on this site can be found at MediaWiki:FixMe.css.