Have now upgraded to 3.2.2. Did you check to see if the fix was made to webtress theme Nigel? If not could you please let me the fix.
The fix wasn’t added to any core code. I’m still looking for a better solution. But the one provided to mac does work (it just spoils a recent “improvement” that works in all other browsers 🙁 ) The fix is described in http://kiwitrees.net/forums/topic/colours-theme-woes-2/#post-6519. Just read “webtrees’ theme wherever colors is mentioned in the discussion.
For further general info about customising themes see http://kiwitrees.net/customising-themes/