The purpose of MediaWiki:Vector.css and MediaWiki:Vector.js is to augment the MediaWiki CSS and JS code in ways that are tailored to, or necessary to improve, the Vector skin. Vector is the default skin, and thus probably used by all registered users. Therefore, although wiki-wide changes are typically made to MediaWiki:Common.css and MediaWiki:Common.js, the changes to these Vector pages will override those changes for the average user. On top of any changes to Vector or Common pages come any changes made to users' local vector.css and vector.js pages.
- Vector.css starts off by anchoring the sidebar in place so that scrolling down an article does not affect the sidebar's position.
- The background of the code style (the style applied to any line of text that begins with at least one space character) is darkened, for better contrast against the standard page background.
- The text in the wiki's diff view is made normal size, for better readability.