Converting CSS to Tailwind

Migrate plain CSS files to Tailwind utility classes applied directly in markup.

Workflow

1. Read the CSS file and inventory every rule
2. Find the corresponding markup (HTML, JSX, TSX, Vue, Svelte) that references each selector
3. Convert each rule using the mapping below
4. Delete the CSS rule once all its properties are expressed as utilities
5. Remove the CSS file (or import) once it's empty
6. Verify the page looks identical — check for visual regressions

Conversion Reference

Layout & Box Model

Typography

Backgrounds & Borders

Responsive — Media Queries

@media (min-width: 768px) { .card { flex-direction: row; } }

→ <div class="flex-col md:flex-row">

Map breakpoints: sm: (640), md: (768), lg: (1024), xl: (1280), 2xl: (1536)

Pseudo-classes & States

.btn:hover { background-color: #1d4ed8; }

→ <button class="hover:bg-blue-700">

Prefixes: hover:, focus:, active:, disabled:, first:, last:, odd:, even:, group-hover:, peer-checked:

Animations & Transitions

transition: all 0.2s ease-in-out;

→ transition-all duration-200 ease-in-out

@keyframes spin { ... }
animation: spin 1s linear infinite;

→ animate-spin (built-in) or define in tailwind.config

Custom Properties / Arbitrary Values

For anything without a direct utility, use arbitrary values:

• w-[calc(100%-2rem)]
• grid-cols-[200px_1fr_1fr]
• text-[clamp(1rem,2vw,1.5rem)]

Handling Remaining CSS

Some things can't be expressed purely as utilities:

• Complex selectors (.parent > .child + .sibling) — restructure the markup or use @apply as a last resort
• @font-face — keep in a global CSS file or globals.css
• Complex @keyframes — define in tailwind.config.ts under theme.extend.keyframes
• CSS variables — migrate to Tailwind theme values in tailwind.config.ts

Rules

• Prefer semantic Tailwind classes (bg-primary) over arbitrary hex values when a theme exists
• Don't use @apply to recreate the same CSS you're migrating away from — that defeats the purpose
• Group related utilities logically: layout → spacing → typography → colors → effects
• If a component has 10+ utilities, consider extracting a reusable component rather than a CSS class