Short description
Tables of contents are produced as a plain ordered list which does not belong to any class and does not have any id. Thus, it is not possible to alter the appearance of the table with a style sheet. The list should be enclosed in a <div> to make this possible.
Interestingly, the rst formatter does this; the table of contents produced with the ".. contents" directive is enclosed in <div class="contents topic" id="contents">.
True, toc should have an id. The reason it does not have one (and also many other parts) is that the formatter interface does not support div or class and id on lists.
Patches
I've created a patch which I think implements your request. See MoinMoinPatch/AlterTableOfContentsAppearanceWithStyleSheet -- DeronMeranda 2006-01-12 20:42:14
Committed as moin--main--1.5--patch-561.