Design and custom CSS

Settings → Design (/settings/design).

Layout background

Applies to the main chrome (dashboard, settings), not necessarily every project board background.

• Dynamic background — default animated/gradient treatment
• Static background — pick a hex color

Save and reload if the preview does not apply immediately.

Project board backgrounds are separate: set per project (Projects), including custom image upload (project/background/upload/{id}).

Custom CSS

A large textarea injected as extra CSS for the app. Use it for small branding tweaks. Invalid CSS can hide controls — keep a backup of the previous snippet.

The same kind of field may also appear on Global settings depending on version; Design is the dedicated screen.