CSS Usage#

Builder has built-in multiple style resource processing capabilities, including Less / Sass preprocessor, PostCSS, CSS Modules, CSS inline and CSS compression.

In addition, Builder also provides multiple configs to customize the compile rules of style resources.

Using Less, Sass and Stylus#

The Builder has built-in community popular CSS preprocessors such as Less, Sass.

By default, you don't need to configure anything for Less and Sass. If you need to customize loader config, you can configure tools.less, tools.sass to set it up.

You can also use Stylus in Builder, just install the Stylus plugin provided by Builder, please refer to Stylus Plugin for usage.

Using PostCSS#

Builder has built-in PostCSS to transform the CSS code. You can configure the postcss-loader via tools.postcss.

export default {
  tools: {
    postcss: opts => {
      const viewportPlugin = require('postcss-px-to-viewport')({
        viewportWidth: 375,
      });
      opts.postcssOptions.plugins.push(viewportPlugin);
    },
  },
};

Builtin PostCSS plugins#

Builder has some builtin PostCSS plugins, which will perform the following transformations on CSS:

• autoprefixer: we have enabled autoprefixer to add vendor prefixes to CSS rules. If you want to configure the target browser, you can use output.overrideBrowserslist config.
• postcss-nesting: Provide CSS Nesting support, you can Use nested writing in CSS, such as:

.my-table {
  & td {
    text-align: center;

    &.c {
      text-transform: uppercase;
    }
  }
}

• postcss-flexbugs-fixes: Used to fix known Flex Bugs.
• postcss-initial: Enabled only when it needs to be compatible with legacy browsers, providing the initial attribute value compatible.
• postcss-page-break: Enabled only when compatibility with legacy browsers is required, providing support for break- attribute.
• postcss-font-variant: Enabled only when compatibility with legacy browsers is required, providing support for font-variant.
• postcss-media-minmax: Enabled only when compatibility with legacy browsers is required, providing support for Media Query Ranges compatibility.
• postcss-custom-properties: Only enabled when compatibility with legacy browsers is required, providing support for Custom Properties, you can define and use custom variables in CSS, such as:

:root {
  --main-bg-color: pink;
}

body {
  background-color: var(--main-bg-color);
}

CSS Minify#

Usually, in production environments we compress static assets such as CSS, JS, etc. to achieve better transfer efficiency.

Builder automatically compresses CSS code at production build time with css-minimizer-webpack-plugin (The compression tool used at the bottom is cssnano).

You can configure tools.minifyCss to make it more customizable.

Inline CSS Files#

By default, Builder will extract CSS into a separate .css file and output it to the dist directory.

If you want to inline styles into your JS file, you can set output.disableCssExtract to true to disable CSS extraction logic.When the JS file is requested by the browser, JS dynamically inserts the <style> tag into the Html to load the CSS styles.

export default {
  output: {
    disableCssExtract: true,
  },
};

This will increase the size of your JS Bundle, so it is usually not recommended to disable the CSS extraction.

Import CSS in node_modules#

You can directly import CSS files in node_modules.

• Import in a component:

// Import the Arco Design style:
import '@arco-design/web-react/dist/css/arco.css';

• Import in a style file:

/* reference normalize.css */
/* https://github.com/necolas/normalize.css */
@import 'normalize.css';

body {
  /* */
}