postcss-cssnext featuresautomatic vendor prefixes custom properties & `var()` custom properties set & `@apply` reduced `calc()` custom media queries media queries ranges custom selectors nesting `image-set()` function `color()` function `hwb()` function `gray()` function `#rrggbbaa` colors `rgba` function (`rgb` fallback) `rebeccapurple` color `font-variant` property `filter` property `initial` value `rem` unit (`px` fal
