lucy24 - 4:19 am on Oct 18, 2011 (gmt 0)

Look through all your browsers' prefs. I assume you have at least five. Pick the one that has the quickest and easiest way to enable or disable a user style sheet. In general, these take precedence over site styles. Some browsers have an "always use my styles" option. (Take that, !important rule! :-P)