[spawnia]

The library ships index.css unminified, with a second, unprefixed copy of some antd 4 styles.
Consumers that inline it as a JavaScript string, such as through style-loader, ship all of it.

esm/index.css	Raw	gzip
Before	903,158 bytes	93.1 KB
Minified with cssnano	740,843 bytes	85.0 KB
Without the unprefixed copy	590,687 bytes	68.8 KB

The unprefixed copy styles no component of the library

Grid and DatePicker imported antd/es/grid/style/index and antd/es/date-picker/style/index.
rollup-plugin-styles compiled those without the @ant-prefix: mll-ant of src/antd.less, so they emitted .ant-row, .ant-btn, .ant-tag and a second copy of antd's base styles.
Provider sets prefixCls: 'mll-ant', so components render only mll-ant- classes.
src/antd.less covers the same components with the prefix: .mll-ant-col-8, .mll-ant-row, .mll-ant-picker, .mll-ant-btn and .mll-ant-tag all remain.

A consumer that still runs antd 3 got these rules on its own .ant- elements.
Removing them can change how such a consumer looks, so the alpha below gets a visual check there.

The copy also carried antd's base styles in the default theme, after the compact ones.
They set body to font-size: 14px; line-height: 1.5715, so Storybook and consumers that leave body to the library now get the compact 12px; 1.337.

cssnano keeps every @Keyframes, @media and !important declaration

Compared before and after minifying:

• 61 @keyframes and 32 @media in both. Dropping the unprefixed copy then removes 5 @media of its grid.
• Every !important declaration stays. The count drops from 101 to 95 only because cssnano merges identical rules and shortens values, such as rgba(0, 0, 0, 0.85) → rgba(0,0,0,.85).
• url('#linearGradient-1') of the Empty image stays as written.

A per-module build would save a consumer that uses most components little, so it stays out

A prototype shipped each module with preserveModules and compiled one prefixed stylesheet per antd component, imported by the modules that use it.
Measured with webpack 5 in production mode, honoring sideEffects:

Consumer bundle	CSS today	CSS per module	JS today	JS per module
116 of 151 exports, as our main consumer uses	591 KB (68.5 KB gzip)	549 KB (64.2 KB gzip)	2.30 MB (609 KB gzip)	2.36 MB (625 KB gzip)
Button only	591 KB	61 KB	2.22 MB	225 KB

It pays off only for consumers that use a few components.
It would be a major release: esm/index.css goes away, the CSS loads through side-effect imports that need a CSS-capable bundler or a Jest mapper, and antd resolves from the consumer's node_modules.

For agents 🤖: visual check passed, in review by mic-web

• Two commits: minimize: true in styles() of rollup.config.js, then the two style imports removed from src/Grid/index.tsx and src/DatePicker/index.tsx. cssnano 5 comes with rollup-plugin-styles 4, so no new dependency.
• 21.0.1-alpha.1 is published from the alpha branch, reset to this branch. The visual check in a consumer passed: screenshots of 9 pages identical, only inert antd 3 declarations changed. Next: merge.
• perf: gives a patch release through semantic-release.
• Six unprefixed selectors remain, .ant-divider-inner-text and .ant-motion-collapse*, from antd/dist/antd.less itself.
• Storybook compiles every .less through less-loader in .storybook/main.ts, so it showed the unprefixed copy too. Its body text drops from 14px to the compact 12px; components keep their prefixed styles from src/antd.less.
• Build output for comparison is untracked: yarn build on the branch writes esm/index.css.
• The per-module prototype is uncommitted on the local branch per-module-build-prototype. Its side findings, unverified: the source mixes antd/lib and antd/es imports, which can yield two copies of the ConfigProvider context, and babel-plugin-import never runs on .ts/.tsx.

🤖 Generated with Claude Code

[github-actions]

🎉 This PR is included in version 21.0.1-alpha.1 🎉

The release is available on:

• npm package (@alpha dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[github-actions]

🎉 This PR is included in version 21.0.1 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀