Tilix supports themes for configuring the color scheme of the terminal, each theme is stored in a file. A theme file is a simple json file that specifies the color for each element as well as identifying whether certain colors should be used or defaulted. Here is an example of a theme file:
Themes are loaded from one of two places by Tilix. The first is
/usr/share/tilix/schemes, these are the themes that are shipped with Tilix. The second place that Tilix looks for theme files is in the user home directory, specifically
~/.config/tilix/schemes. Users can place any custom themes they want to use here.
While Tilix only includes a small number of themes, additional themes can be easily downloaded and installed. For instance, there are a couple of GitHub repositories as Tilix-Themes and gogh-to-tilix which have various pre-built themes.