Stylish (or whatever the equivalent is for your favorite browser) is always an option until a better design comes along. For example, if you don't use the details boxes that much, you can apply something like

div#repo_details { opacity:0.3 !important; } ul.with-details-box { opacity:0.3 !important;}

to make those fade a bit and draw you eye toward the menu bars below them. You could event apply it your specific repo urls, so you could customize it depending on what you're working on.

Again, only a temporary hack, but better than nothing until a better universal design can be agreed upon and implemented.

Stylish: https://addons.mozilla.org/en-US/firefox/addon/stylish/