From NeoWiki - Wiki on Neoseeker

TOC Alignment

When 4 or more headers are created in a wiki page the Wiki software will automatically create a TOC (Table of Contents). These tend to be very narrow and can get quite long, so it is proposed that long TOCs are left or right aligned with the content to improve readability and aesthetic of the page.

TOC Aligned vs Unaligned

Compare the two images below:

Without aligment:

With alignment:

(You can see the above page here)

Code to Align TOC

 {| style="margin-right:1em;" align="left"
 | __TOC__
 |}