Please add a 'chrome://browser/skin/aboutAccount.css' to browser/base/content/aboutaccounts/aboutaccounts.xhtml, so that themes such as Walnut can also style this page.

Alfred, can you explain more about how the skinning system works? We've modeled about:accounts after about:healthreport; does about:healthreport need additional work too? I'm assuming we'd need to make changes for this kind of skinning work on mobile, too. Can you point me at an example for mobile, too? For the record, on mobile, at http://mxr.mozilla.org/mozilla-central/source/mobile/android/chrome/content/aboutAccounts.xhtml#23 we reference http://mxr.mozilla.org/mozilla-central/source/mobile/android/themes/core/aboutAccounts.css Thanks for filing!

about:accounts is just an iframe to remote content, it doesn't make sense to style it from a Firefox theme.

The "address" about:accounts indicates that it is a page from Firefox itself, not a hosted/remote page. It is in no way clear that it is a remote page (with all its security issues). But if it is really meant as part of Firefox itself (even if remote hosted), then it should be styled as being part of Firefox itself. Also in the case when a theme is applied.

We're not going to support styling this page from a theme.