You might want to clear your browser cache on your IE, it looks the same to me perhaps you could be detailed after clearing your cache as I didnt see any differences.

The style.css should read pretty much identical regaurdless of browser

The only difference in .css that comes to mind is the scroll bar which is able to be edited for IE such as adding

/*Only IE will show for the scroller style */
BODY {
SCROLLBAR-FACE-COLOR: #17171C;
SCROLLBAR-HIGHLIGHT-COLOR: #35353F;
SCROLLBAR-SHADOW-COLOR: #303030;
SCROLLBAR-3DLIGHT-COLOR: #4D4E53;
SCROLLBAR-ARROW-COLOR: #00FF00;
SCROLLBAR-TRACK-COLOR: #3C3C42;
SCROLLBAR-DARKSHADOW-COLOR: #000000;
 }

To clear cache

1. clear all browser cookies, cache/temporary internet files, and history.
2. update all bookmarks related to the domain you are attempting to access.
3. reload the browser.
4. try accessing the domain(s) using http://www.megaproxy.com/freesurf/ or http://www.proxify.com/
5. Windows 2000/XP and MAC users, please clear your DNS cache by doing:

Windows 2000:
a. go to start,  run
b. type:  ipconfig /flushdns

Windows XP:
a. go to start , run
b. type: ipconfig /flushdns

MAC:
a. open a terminal window
b. type: lookupd -flushcache

Windows 98/98SE/ME:
there is no dns cache flush option on these operating systems. (restarting pc may help).

Could be just the difference in font settings with the browser itself the issue of the text you noted I dont think are controled by the style.css more of in the post itself such as <font size=2>

Hope this helps