Normalize unicode-range descriptors, and can convert to wildcard ranges.

Reduce transform functions with PostCSS.

SCSS parser for PostCSS

Normalize URLs with PostCSS

Nest rules inside each other in CSS

Trim whitespace inside and around CSS rules & declarations.

Normalize CSS animation/transition timing functions.

PostCSS plugin to transform :not() W3C CSS level 4 pseudo class to :not() CSS level 3 selectors

Merge longhand properties into shorthand with PostCSS.

Ensure CSS selectors are unique.

Use the :focus-visible pseudo-selector in CSS

Use two values display syntax for inner and outer display types.

Use the :focus-within pseudo-selector in CSS

PostCSS plugin to transform percentage-based opacity values to more compatible floating-point values.

Use unquoted format on @font-face CSS definitions.

Use a place-* shorthand for align-* and justify-* in CSS

Use the ic length unit

Use 4 & 8 character hex color notation in CSS

Discard duplicate rules in your CSS files with PostCSS.

Use the overflow shorthand in CSS