100 handcrafted themes with living, animated backgrounds — from quiet dark modes to cherry blossoms, aurora, and a tiny T‑Rex. One click, both platforms.
Three quick steps — and one that really matters.
Install Vellum free from the Chrome Web Store. It works on both Claude and ChatGPT — no account or setup needed.
In Claude or ChatGPT settings, set appearance to Dark. Vellum's themes are crafted for dark mode — on light mode they'll look washed out.
Click the Vellum icon in your toolbar, choose any theme, and it applies instantly across the whole interface.
Why dark mode? Vellum's animated backgrounds and palettes are designed to glow against a dark interface. If a theme looks faded, you're still in light mode — switch your AI app to Dark in its appearance settings and it'll come alive.
21 free · 79 Pro
Pick a theme and it applies at once — sidebar, composer, buttons, scrollbars. The entire interface, retuned.
Cherry blossoms, northern lights, rising embers, a retro synthwave grid. Subtle enough to work against, striking enough to enjoy.
No tracking, analytics, or telemetry. Everything runs in your browser; only your theme choice syncs through Chrome.
Every install starts with a 7-day Pro trial. Keep 21 themes free forever, or unlock all 100.
100 themes. Two platforms. One click. Free to start.
Add to Chrome — Free