## What kind of change does this PR introduce?
Chore.
## What is the current behaviour?
Classic Dark remains available across the shared theme library and
several apps. Studio now supports System, Dark, and Light as its theme
modes, but still carries compatibility paths for Classic Dark.
## What is the new behaviour?
- Removes Classic Dark from shared theme options, application commands,
stylesheets, previews, examples, and replay handling.
- Deletes the Classic Dark and faux Classic Dark stylesheets.
- Removes the now-unused Classic Dark branches from Studio theme colour
controls.
- Migrates `classic-dark` to `dark` so first rendered frame renders Dark
(not Light)
| After |
| --- |
| <img width="1458" height="1778" alt="CleanShot 2026-09-18 at 11 07
40@2x"
src="https://github.com/user-attachments/assets/679bf87f-a3c1-4599-ad2f-292d98d0b856"
/> |
## To test
1. In Studio, open Account Preferences → Appearance. Confirm the
available themes are System, Dark, and Light, and that theme colour
controls still work in each resolved mode.
2. Set the `theme` local storage value to `classic-dark`, then reload
Studio. Confirm it renders as Dark immediately and the stored value
becomes `dark`.
3. Open the theme switcher in Design System, Learn, and UI Library.
Confirm Classic Dark is no longer available and Light, Dark, and System
still apply correctly.
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **Changes**
* Removed the Classic Dark theme option from theme menus and settings
across the application.
* Classic Dark selections are automatically migrated to the standard
Dark theme.
* Updated theme documentation and demonstrations to list only System,
Light, and Dark.
* Removed Classic Dark styling and preview support; existing Dark,
Light, and System themes remain available.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
## I have read the
[CONTRIBUTING.md](https://github.com/supabase/supabase/blob/master/CONTRIBUTING.md)
file.
YES/NO
## What kind of change does this PR introduce?
Bug fix, feature, docs update, ...
## What is the current behavior?
Please link any relevant issues here.
## What is the new behavior?
Feel free to include screenshots if it includes visual changes.
## Additional context
Add any other context or screenshots.
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **New Features**
* Refreshed theming across the UI to use modern color expressions and
shared theme variables (including OKLCH-based gradients), improving
consistency for charts, code blocks, overlays, icons, and decorative
backgrounds.
* **Bug Fixes**
* Improved light/dark color and gradient consistency across axis/grid
styling, reference lines, buttons/badges, sidebar accents, loaders, and
other visual components.
* **Documentation**
* Updated styling/theming guidance to align with the revised semantic
token system and the updated theme variable usage patterns.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
---------
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **Chores**
* Updated React Router packages to v7.17.0 for improved routing
stability.
* Adjusted workspace dependency governance and overrides for more
consistent installs.
* Removed an obsolete PostCSS re-export.
* **New Features**
* Integrated Tailwind into the build pipeline to enable utility-first
styling.
* **Style**
* Added global base styles to standardize border color across UI
elements.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
This PR migrates all tailwind configs in the apps to be CSS configs.
They import a shared CSS Tailwind config from the `config` package
(which in turns imports the old JS config).
The shared JS config will be migrated to CSS in a followup PR.
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **Chores**
* Centralized Tailwind into a config-driven entrypoint and updated the
app build flow to use the new build step; many apps now import unified
global styles.
* **Style**
* Migrated global styles to a Tailwind v4-style setup, added
project-wide content scanning, consolidated theme imports, standardized
theme tokens (including new --container-site max-width), and added a
small prose utility to remove paragraph margins.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
---------
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Danny White