[TweedHeads]

Here is what I'd do, start from here:

  <div class="comment level0">
    <a class="up"></a> 
    <a class="dn off"></a>
    <h1>title</h1>
    <p class="minus2">comment here</p>
  </div>

Then apply styles at will, increase padding per level and dimming per negative karma.

I bet code size decreases while readability increases.

[zepolen]

No need to use class 'levels', as nested <li>'s shows in regards to padding.