Getting rid of Comic Sans in Firefox

Test page: the Microsoft Comic Sans Café.
Original look:

How to get rid of Comic Sans for Mozilla Firefox

1. Look for the following folder: %userprofile%\Application Data\Mozilla\Firefox\Profiles\chrome under Windows or the equivalent under your OS.
2. Create a file named userContent.css in it. If it already exists, you can simply append the following at the end of it.
3. Copy-paste the following line into it: @font-face { font-family: 'Comic Sans MS'; src: local('Lucida Sans Unicode'); }
4. Lucida Sans Unicode is a good choice because it has approximately the same height and weight as Comic Sans MS, but you can replace it with any other font, such as Arial, Deja Vu Sans or Century Gothic.
5. Save the file and restart Firefox.

Resulting look: