Easy, take out the IE fix; it's ugly, bulky, and is of no use to just about anyone (I'm more than willing to sacrifice a small inconvenience to IE users at the stake of a conforming design).

Defaults:
.ubbcode-block
Code
width: 508px;
margin: 5px 2em;
border: 1px solid #000000;
padding: 0px;
border-spacing: 0px;

.ubbcode-body
Code
width: 500px;
margin: 4px;
overflow: auto; 
font-size: 10pt;
display: block;

Replace those with something similar to:
.ubbcode-block
Code
margin: 5px 2em;
background: #081750;
border: 1px solid #000000;
padding: 0px;
border-spacing: 0px;

.ubbcode-body
Code
margin: 4px;
max-width: 100%; 
max-height: 300px; 
overflow: auto; 
font-size: 10pt;
display: block;

Now your muti-level quotes, spoier tags, code boxes will actually conform to your forum design and will no longer be "bonkers"

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