Template:Wikitable fluid

Wikitable fluid isn't a transcluded template — it exists only to hold Template:Wikitable fluid/styles.css, the stylesheet for the wikitable--fluid modifier class. Add the class alongside wikitable and load the stylesheet to get a full-width table with word-wrapping cells:

{| class="wikitable wikitable--fluid"
...
|}

This lives here instead of MediaWiki:Common.css because that page requires interface-admin rights this account doesn't have.