You can override the GTK theme that Zrythm uses along with much of the color scheme in a special CSS file. It is a good idea to start by copying the theme from your Zrythm installation directory (normally /usr/share/zrythm/themes/zrythm-theme.css on GNU/Linux and share/zrythm/themes/zrythm-theme.css in the installation path on Windows or the Application contents on MacOS.

You should create a file called theme.css under the themes directory in your Zrythm directory. For example, if your Zrythm directory is /home/me/zrythm, you should create a file at /home/me/zrythm/themes/theme.css.

Color Scheme#

Inside the theme file, you will find lots of colors defined using @define-color. You can override these with your own colors and Zrythm will use them where possible.

Other GTK-Specific Rules#

You will find lots of information about changing CSS rules for general GTK widgets online.

Here are some links by official GNOME sources: