I'm glad to announce this to you.
After removing the GTK+-2.0 support, I was able to use some
features of GTK+-3.0 which are not available on
GTK+-2.0. Features such as CSS theming.
Instead of loading a GtkRc file, GTK+-3.0 loads a CSS
In my opinion, GtkRc is a big shit. If I wanted to keep GTK+-2.0,
I had to use the GtkWidget tuning functions.
In other words : a painful trip. Another good reason to remove GTK+-2.0
If you don't want to use the default GTK theme, just put
your custom CSS file into ~/.config/cream-browser/theme.css
An example of CSS theme is already available on the git