Tailwind CSS theme editor

Utility classes and no components; the theme is CSS variables you can override. UISandbox builds Tailwind CSS 4.3.3 from its own package and opens it in the editor: seven screens in Tailwind CSS's own components and its own defaults. Turn the brand, the type, the spacing and the corners, and every component follows. Nothing to install, nothing uploaded.

Open Tailwind CSS in the editor Try it on your own app

Tailwind CSS in the UISandbox editor: the knobs on the left, Tailwind CSS's own components on the right — Tailwind CSS as it ships, in the editor. A real screenshot.

What is read from Tailwind CSS

Version: 4.3.3
Licence: MIT
Package: tailwindcss
Runs in: any page, no framework asked
Variables: 419 in its light mode, read from its package
Brand as it ships: #4f39f6
Body type: the system stack
Corners: 6px

What you take with you

Export writes Tailwind CSS's design system in Tailwind CSS's own names, starting from what you see:

theme.css: the variables, in Tailwind CSS's own names, as the knobs left them
install.md: where each file goes, step by step
MANIFEST.md: what could not be done, said rather than substituted
DESIGN.md: the design system for people and agents: colours, type, spacing, what each is for
.claude/skills/design-system/SKILL.md: for Claude Code, Cursor or Codex: build the next screen in Tailwind CSS's own classes
tokens.json: W3C design tokens, which Tokens Studio and Figma variables import

On your own app

If your app runs on Tailwind CSS, the sandbox recognises it from the rendered page and writes the design system in Tailwind CSS's names from your app's own values. What you turned on the kit comes with you. The quickest way in is the one where nothing leaves your machine: run npx uisandbox-mcp open in your project, or ask your agent to "open this app in UISandbox". How it works.