1.4 #permalink .pagesize
Restricts the maximum width a element can have and centers it if the surrounding space is big enough to do so. The example shows a common use case, where you want the section to span the whole surface area while the content should not exceed a certain width
Examples
Default styling
Content
.pagesize--expanded
Modify the section to ignore any set max width
Markup
<div class="section">
<div class="pagesize {modifiers}">
Content
</div>
</div>
Source:
globals.css, line 97