docs: add how to skip the preprocessing of less/scss files (#623)

Author: Timeless0911

website/docs/en/guide/faq/features.mdx

@@ -1,5 +1,38 @@
 # Features FAQ
 
+## Style Processing
+
+### How to skip the preprocessing of Less / Sass files in bundleless mode?
+
+Bundleless means that each source file is compiled and built separately, which can be understood as the process of code conversion of source files only. To skip the preprocessing of `.less/.scss` files, you need to:
+
+1. Set `source.entry` to remove `.less/.scss` files from the entry.
+2. Set `output.copy` to copy `.less/.scss` files to the output directory.
+3. Set `redirect.style` to `false` to disable the redirect behavior for the import path of `.less/.scss` files.
+
+Below is an example of skipping the `.scss` file processing. All `.scss` files in `src` will be copied to the output directory and retained with consistent relative paths.
+
+```ts title="rslib.config.ts"
+export default defineConfig({
+  lib: [
+    {
+      // ...
+      source: {
+        entry: {
+          index: ['./src/**', '!src/**/*.scss'],
+        },
+      },
+      output: {
+        copy: [{ from: '**/*.scss', context: path.join(__dirname, 'src') }],
+      },
+      redirect: {
+        style: false,
+      },
+    },
+  ],
+});
+```
+
 ## Code Minification
 
 ### How to preserve all comments in the output files?

website/docs/zh/guide/faq/features.mdx

@@ -1,5 +1,38 @@
 # 功能类问题
 
+## 样式处理
+
+### bundleless 模式如何跳过对 Less / Sass 等文件的预处理？
+
+bundleless 是指对每个源文件单独进行编译构建，可以理解为仅对源文件进行代码转换的过程。跳过对 `.less/.scss` 文件的预处理需要：
+
+1. 设置 `source.entry` 将 `.less/.scss` 文件从入口里移除。
+2. 设置 `output.copy` 将 `.less/.scss` 文件拷贝到产物目录。
+3. 设置 `redirect.style` 为 `false` 禁用对 `.less/.scss` 文件导入路径的重定向行为。
+
+下面是一个跳过 `.scss` 文件处理的例子，`src` 里面所有的 `.scss` 文件都会被拷贝到产物目录下并且保留一致的相对路径。
+
+```ts title="rslib.config.ts"
+export default defineConfig({
+  lib: [
+    {
+      // ...
+      source: {
+        entry: {
+          index: ['./src/**', '!src/**/*.scss'],
+        },
+      },
+      output: {
+        copy: [{ from: '**/*.scss', context: path.join(__dirname, 'src') }],
+      },
+      redirect: {
+        style: false,
+      },
+    },
+  ],
+});
+```
+
 ## 代码压缩
 
 ### 如何保留产物文件代码中的注释？