Customisation (?page=customisation) controls the visual theme and layout preferences for the whole app, including a custom CSS editor for advanced tweaks.
Step-by-step
Go to Settings → Customisation.
Pick a built-in theme (options include Default, Ocean, Midnight, Rose, Slate, Emerald, Violet, Amber, Arctic, Crimson, Dusk, Nord, Sakura, Obsidian, Sand, Neon, or Custom).
If choosing Custom, use the CSS editor to write your own overrides.
Save — the theme applies clinic-wide for all staff.
Common issues & fixes
switch back to a built-in theme temporarily while fixing the custom CSS, since it applies globally.
confirm they've refreshed/hard-reloaded; cached styles can persist briefly.