This makes it easier to keep baseline alignment between labels and their
respective inputs. Declaring `margin-left: 51%;` for the post-input notes
is not exactly what we want, but it's much closer and less troublesome than
dealing with the vertical alignment of labels otherwise.
This avoids a situation where multiple summaries have floats that stack on
top of each other vertically, which end up getting far away from the actual
text.
In order to make this work, we had to change the styling of #mainContent on
blog pages (and others with a sidebar). Otherwise, headlines with
class="clear" would clear the sidebar as well.
