The design grid consists of 12 columns, each 60 pixels wide with a 20 pixel gutter space between them giving a total of 960px wide.
Columns
Masthead - Home
Masthead - Content Pages
Correct mark up examples
A three column section
<div class="container-12"</div>
<div class="grid-4">
<p>...</p>
</div>
<div class="grid-4">
<p>...</p>
</div>
<div class="grid-4">
<p>...</p>
</div>
</div>A main column with sidebar
<div class="container-12"</div>
<div class="grid-8">
<p>...</p>
</div>
<div class="grid-4">
<p>...</p>
</div>
</div>A smaller main column with sidebar
<div class="container-12"</div>
<div class="grid-4 suffix-4">
<p>...</p>
</div>
<div class="grid-4">
<p>...</p>
</div>
</div>