Qt applications look acceptable in Gnome 3, but with the Qt4 Configure utility you can change the colours and fonts to match their GTK+ brethren.
Installing Qt4 Configure
This is a potential gotcha; depending on your distribution you may have to specify qt4, or not. For example, in Fedora:
# yum install qt-config
# cd /usr/ports/misc/qt4-config # make install clean
Once you've installed it, a beautifully large Qt4 Configure icon should appear in the "Other" category of your Gnome 3 Shell. Given many of my GTK+ applications still have crappy icons, having the Qt4 Configure app fit in so well was a pleasant surprise!
The default GTK+ theme for Qt looks passable, but Gnome 3 uses a whiter shade of pale. This is most noticeable between the title and menu bar in Qt applications.
You can correct this by clicking "Button Background" and "Window Background" under "Build Palette", and slotting in the following values:
- Red: 239
- Green: 235
- Blue: 231
To get the right shade of blue for selected menu items, click "Tune Palette…" under "Build Palette", then choose "Highlight" under "Central color roles". Slot in the following values:
- Red: 74
- Green: 144
- Blue: 217
I derived these colours from using the GColor2 utility, so they may be approximations. I can't tell the difference!
For better or worse, Gnome 3 uses Cantarell for its default font. To get Qt applications to match, set the font to "Cantarell" on the "Family" dropdown box under the "Fonts" tab.
Curiously, I had to go through this rigmarole on my Fedora 16 x86_64 tower, but on my MacBook Pro running Fedora 16 i686, Qt had the right colours set for Gnome 3 by default.
I've since discovered it has to do with installation order. If you install Qt4 Configure before any Qt applications such as VirtualBox, Amarok or Opera, the Gnome 3 colours will be included by default. Interesting!