Skin:Vector/Customizing the logo for special events

Many projects feature custom logos to celebrate certain events, milestones, or even to distinguish special features within a wiki (See Category:Wikipedia_commemorative_logos).

These custom logos will not appear on modern Vector without changes to MediaWiki:Common.css on your wiki.

Legacy Vector
In Vector classic the logo is provided purely by CSS and thus a CSS only change can substitute the logo for another.

The way these logos have been customized traditionally in Vector is by adding this CSS MediaWiki:Common.css:

To customize the logo on MediaWiki:Common.css page in modern Vector:
It is possible to customize the logo for special events. In modern Vector the mechanisms are different.

In the Vector modern version the logo cannot be substituted but can be decorated using CSS pseudo elements as in the examples in this page.

Example 1 - Wikipedia logo with a party hat
Code:

Example 2 - decoration
You can use the :before and :after pseudo elements to add 2 images and also target the wordmark and logo separately.