Unreadable text/ugly lines in nautilus gear menu

[bwat47]

In 13.04 with the default ambiance theme the nautilus gear menu just looks awful with heavy black lines, and there's also a usability issue of unreadable (white-on-white) text on the right.

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: light-themes 13.04daily13.04.12-0ubuntu1
ProcVersionSignature: Ubuntu 3.8.0-19.29-generic 3.8.8
Uname: Linux 3.8.0-19-generic x86_64
ApportVersion: 2.9.2-0ubuntu8
Architecture: amd64
Date: Sat Apr 20 10:16:24 2013
InstallationDate: Installed on 2013-04-17 (2 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Alpha amd64 (20130416)
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: ubuntu-themes
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.