Your brand kit lives on Settings → Branding (under Your store) and is set per dealership: each dealership in your group has its own logo and colors. The page has one section, Brand theme, with a Booking page preview below it. The brand kit styles the customer booking page and its emails. The website chat widget's look is kept separate, on Settings → Website in its Widget appearance section, so you can tune the chat window on its own.
The website chat window is styled separately from the booking page. Go to Settings → Website, section Widget appearance: set its Primary Color and Theme Mode (Dark or Light), check the Live preview, then click Save changes.
Does this change the admin portal's appearance?
No. The Branding page only styles what customers see (the booking page and its emails; the chat widget's look is on Website). The AutoBook screens your team uses are unaffected.
My group has several dealerships. Do I set this once?
No. Branding is per dealership, so each dealership configures its own logo and colors. Switch to each dealership and set its kit separately.
What logo file should I use?
Any common image type works, including SVG (which is converted to PNG for email). A square image at least 200×200px gives the best results across the booking header and emails.
Why don't I see a favicon or accent-color option?
Those aren't part of the current Branding page. The page has Preset theme, Custom logo, Primary color, and Background color. The chat widget's Primary Color and Theme Mode are on Settings → Website.
How do my changes go live?
Edit your theme, then click Save changes in the bar at the bottom of the page. The preview shows your edits immediately; saving applies them to that dealership's booking page and emails.