diff --git a/package.json b/package.json
index 1c7bfd537f..d04ee43024 100644
--- a/package.json
+++ b/package.json
@@ -34,7 +34,9 @@
     "dist",
     "es"
   ],
-  "sideEffects": false,
+  "sideEffects": [
+    "*.less"
+  ],
   "main": "dist/antd.js",
   "module": "es/index.js",
   "unpkg": "dist/antd.min.js",
diff --git a/site/antd.js b/site/antd.js
index d831021e6f..c2ebdc9a4a 100644
--- a/site/antd.js
+++ b/site/antd.js
@@ -1,28 +1,3 @@
-/* eslint no-console:0 */
-function pascalCase(name) {
-  return name.charAt(0).toUpperCase() + name.slice(1).replace(/-(\w)/g, (m, n) => n.toUpperCase());
-}
-
-// Import all the component less file.
-// This is mostly like index.js but we do not need root `themes/index`
-const req = require.context('../components', true, /^\.\/[^_][\w-]+\/style\/index\.less$/);
-
-req.keys().forEach(mod => {
-  let v = req(mod);
-  if (v && v.default) {
-    v = v.default;
-  }
-  const match = mod.match(/^\.\/([^_][\w-]+)\/index\.less$/);
-  if (match && match[1]) {
-    if (match[1] === 'message' || match[1] === 'notification') {
-      // message & notification should not be capitalized
-      exports[match[1]] = v;
-    } else {
-      exports[pascalCase(match[1])] = v;
-    }
-  }
-});
-
 // Need import for the additional core style
 exports.styleCore = require('../components/style/reset.css');
 
diff --git a/site/bisheng.config.js b/site/bisheng.config.js
index 730e00df6c..2e30880a74 100644
--- a/site/bisheng.config.js
+++ b/site/bisheng.config.js
@@ -10,7 +10,6 @@ const themeConfig = require('./themeConfig');
 const { webpack } = getWebpackConfig;
 
 const isDev = process.env.NODE_ENV === 'development';
-const { ANT_THEME, DEV_THEME } = process.env;
 
 function alertBabelConfig(rules) {
   rules.forEach(rule => {
@@ -42,7 +41,7 @@ module.exports = {
     'components/form/v3': ['components/form/v3.zh-CN.md', 'components/form/v3.en-US.md'],
     'docs/resources': ['./docs/resources.zh-CN.md', './docs/resources.en-US.md'],
   },
-  theme: ANT_THEME ? './site/theme/index-css-only.js' : './site/theme',
+  theme: './site/theme',
   htmlTemplate: './site/theme/static/template.html',
   themeConfig,
   filePathMapper(filePath) {
@@ -63,7 +62,7 @@ module.exports = {
   lessConfig: {
     javascriptEnabled: true,
     modifyVars: {
-      'root-entry-name': ANT_THEME || DEV_THEME || 'variable',
+      'root-entry-name': 'variable',
     },
   },
   webpackConfig(config) {
@@ -131,47 +130,6 @@ module.exports = {
       config.mode = 'development';
     }
 
-    if (ANT_THEME) {
-      config.mode = 'development';
-      config.plugins.forEach(plugin => {
-        if (plugin?.options?.filename?.includes?.('.css')) {
-          delete plugin.options.chunkFilename;
-          plugin.options.filename = `${ANT_THEME}.css`;
-        }
-      });
-
-      // Remove preset target
-      config.module.rules.forEach(rule => {
-        if (rule.options?.presets?.[1]?.[0]?.includes('preset-env')) {
-          delete rule.options.presets[1][1];
-          delete rule.options.plugins;
-        }
-      });
-
-      config.optimization.minimize = false;
-      delete config.optimization.minimizer;
-
-      config.externals = [
-        /^rc-.*/,
-        /^react.*/,
-        /^@ant-design\/.*/,
-        /^@babel\/.*/,
-        /^@algolia\/.*/,
-        /^@docsearch\/.*/,
-        /autocomplete.js/,
-        /docsearch.js/,
-        /.*\.md/,
-        /lodash/,
-        /jquery/,
-        /dayjs/,
-        /core-js/,
-        /jsonml/,
-        /ramda/,
-        /tinycolor/,
-        /bisheng-plugin/,
-      ];
-    }
-
     // Split chunks
     if (config.mode === 'production') {
       config.optimization.splitChunks = {
diff --git a/site/theme/template/Content/ComponentOverview.less b/site/theme/template/Content/ComponentOverview.less
index 1f22f8b53b..8d81d0d1e0 100644
--- a/site/theme/template/Content/ComponentOverview.less
+++ b/site/theme/template/Content/ComponentOverview.less
@@ -1,4 +1,4 @@
-@import '../../style/themes/index.less';
+@import (reference) '../../style/themes/index.less';
 
 .components-overview {
   padding: 0;
diff --git a/site/theme/template/Home/Banner/Background.less b/site/theme/template/Home/Banner/Background.less
index 861138f280..a81991f6bb 100644
--- a/site/theme/template/Home/Banner/Background.less
+++ b/site/theme/template/Home/Banner/Background.less
@@ -1,4 +1,4 @@
-@import '../../../style/themes/index.less';
+@import (reference) '../../../style/themes/index.less';
 
 .home-banner-background {
   position: absolute;
diff --git a/site/theme/template/Layout/Header/SearchBar.less b/site/theme/template/Layout/Header/SearchBar.less
index 2fb43ca903..4fdf646477 100644
--- a/site/theme/template/Layout/Header/SearchBar.less
+++ b/site/theme/template/Layout/Header/SearchBar.less
@@ -1,5 +1,5 @@
 @import '../../../static/theme.less';
-@import '../../../style/themes/index.less';
+@import (reference) '../../../style/themes/index.less';
 @import './index.less';
 @import './DocSearch.less';