Recipes and migrations

Tailwind output

When Tailwind emits rem, place postcss-rem-to-responsive-pixel after Tailwind's PostCSS plugin and set the root value to the design system's base font size. If the same stylesheet needs several unit targets, use postcss-rule-unit-converter with a grouped preset.

Platform presets

postcss-pxtrans provides weapp, h5, rn, quickapp and harmony presets. Start from the preset that matches the runtime, then override designWidth, rootValue, or property filters for the project.

Migrating to the rule engine

The focused packages remain useful when their old API is part of your public build configuration. Move to postcss-rule-unit-converter when you need multiple rules or custom transforms. Its migration page contains side-by-side option mapping for postcss-rem-to-responsive-pixel, postcss-rem-to-viewport, and postcss-units-to-px.

Protecting declarations

Use propList for property-level control, selectorBlackList for selectors, and exclude for file-level decisions. The shared matcher behavior is documented in postcss-plugin-shared and is consistent across the conversion packages.