You can set the CSS for individual wiki sites in a farm by adding a Fedwiki Theme Folder to the status folder of the site.
The folder structure for your wiki site looks like this:
example.com/ pages/ ... lots of json files for the sites content status/ favicon.png persona.identity sitemap.json sitempa.xml theme/ style.css
You can dig into the way wiki is styled by playing around with the browser debugging tools. When you find a style you want copy this to the file:
example.com/status/theme/style.css
# Example
Here we show an example CSS file, where we remove the footer, and tweak things to make the wiki translucent if needed. We also need to remove the min-height attribute of .page selctor.
#welcome-visitors { /* option to make first page wider */ /* width: 1000px; */ } #welcome-visitors .journal { /* may want to hide journal only on first page */ /* visibility: hidden; */ } body { /* makes the background translucent */ background: rgba(255,255,255,0.94); } .page { /* resets the bottom from it's wiki setting of 60 */ background-color: transparent; } .main { /* resets the bottom from it's wiki setting of 60 */ bottom: 18px; } .paper { /* resets wiki value of 100% */ min-height: 0; } div.footer { /* sort of deletes the footer rather than just hides it */ display:none; /* visibility: hidden; */ } footer { /* otherwise we have an empty scrolling area */ display:none; /* visibility: hidden; */ } .footer-item { /* visibility: hidden; margin-left: -146px; */ } .journal { display:none; /* visibility: hidden; */ }
You can see what it looks like here - daisy.world 
# See also - Splash Page Creation - How I Shrunk Wiki