To write a custom theme for Catapult, put the following CSS into file
~/.local/share/catapult/themes/hello.css. Then in Catapult, type
:preferences to get to the preferences dialog and you should be able
to select your new "hello" theme. When developing your theme, use
:reload-theme to apply your changes.
@import "@dark@";
@define-color bg-color #ffff55;
@define-color fg-color #2e3436;
@define-color selected-bg-color #3584e4;
@define-color selected-fg-color #ffffff;
.catapult-body {
border-radius: 0;
box-shadow: none;
}