We were using these rules in order to set the maximum width of an
element to `$global-width`. However, since we now do so in the <body>
element, there's no need to apply these rules to "rows".
Note we're adding `overflow: hidden` to the budget subheader. That's
because it only contains `float` element inside, and we're now missing
the `.row::before` and `.row::after` rules which make sure float
elements are rendered properly.
