css doesn't work on Macs for <ul><li> formatting

On Macs, the css doesn't seem to work in formatting a couple <ul><li> components - specifically the "Recently Viewed" bar and the letters buttons to narrow down a search result. I upgraded from civiCRM 2.1 to 2.2 and the problem remained. No problem with Firefox on linux. The browsers affected are Firefox 2 and Safari 3.1 on Macs running OSX.