Low contrast boxes on new documentation webpages

FWIW, on my screen and seen with my eyes, the boxes on the new documentation pages have a background colour almost as bright as the main background. This way, the contrast is reduced compared to the old pages, making quick skimming more difficult.

For instance, look at the code snippets on https://docs.djangoproject.com/en/1.7/intro/overview/ and the adminition boxes on https://docs.djangoproject.com/en/1.7/intro/install/

Compare the code snippets on the overview page and the admonition boxes on the install page linked in the issue, then inspect the documentation site's styling entry points. Done means those boxes are visibly distinct from the main background and easier to skim, with contrast improved over the reported appearance.

Written by the indexing model from the issue text.