Allow admins to add custom CSS to their Nextcloud instance from inside the Theming settings.
Admin can use CSS custom properties to make use of the variables that are available from the default.css variables file file:
Example:
#element {
color: var(--color-primary);
}
The css configuration is stored in the app config database table, but you can use the occ config:app:* commands to obtain, modify or reset it as well. e.g.
occ config:app:get theming_customcss customcss
occ config:app:set theming_customcss customcss --value "body { background-color: red; }"
occ config:app:delete theming_customcss customcss
