The first IE conditional was to make the text smaller so it wouldn’t create a new line (although it’s still indenting).
The other is an old CSS rule I forgot to remove. *makes a mental note of that*
I’ll try sharkbait’s fix.
UPDATE: Oddly enough...
<!--[if IE 7]> <style type="text/css"> .ui-tabs-nav { margin-left: 0px; }</style> <![endif]-->
...worked. I guess setting to the left margin to 0 works (I assume IE7 must have a predefined indent or something). Thanks for all your help.