Cross Browser Wordpress Site Fixes

There are tweaks needed to the wordpress installed at this location [login to view URL] such as but not limited to: z-index's positioning alignments (i.e. in firefox almost everything is set properly, but in internet explorer and safari, background items with a z-index of -1 are showing on top of items with a z-index: 99 etc) Also please review other areas of the site that may be an issue in different browsers, there are only 5-10 pages