Mentioned this before, but filing this as an actual issue so as not to forget: the "+"/"-" icon on expand/collapse controls (in Understanding docs, but then also used quite liberally across WAI pages) is very inconsistent across browsers, and in many cases looks broken (or at least very amateurish). For instance, here's how it renders for me in Chrome/Windows...

Trying to fix the CSS in one browser then leads to broken-looking output in other browsers. It may well require a change in approach (possibly an SVG icon, rather than trying to hack it purely via CSS generated content)
Mentioned this before, but filing this as an actual issue so as not to forget: the "+"/"-" icon on expand/collapse controls (in Understanding docs, but then also used quite liberally across WAI pages) is very inconsistent across browsers, and in many cases looks broken (or at least very amateurish). For instance, here's how it renders for me in Chrome/Windows...
Trying to fix the CSS in one browser then leads to broken-looking output in other browsers. It may well require a change in approach (possibly an SVG icon, rather than trying to hack it purely via CSS generated content)