Basic Grid HTML
To create a simple layout, create a container with a <div> that has a class of .row and
add the appropriate amount of .span* columns. Since we have a 12-column grid, we
just need the amount of .span* columns to equal 12. We could use a 3-6-3 layout, 4-8,
3-5-4, 2-8-2… we could go on and on, but I think you get the gist.
The following code shows .span8 and .span4, which adds up to 12:
<div class="row">
 <div class="span8">...</div>
 <div class="span4">...</div>
</div>
Offsetting Columns
You can move columns to the right using the .offset* class. Each class moves the span
over that width. So an .offset2 would move a .span7 over two columns (see
Figure 1-2):
<div class="row">
 <div class="span2">...</div>
 <div class="span7 offset2">...</div>
</div>