Stylus vs PostCSS

Stylus has an extremely terse syntax. Colons, semicons and braces are all optional allowing you to write Stylus code however you want.

hover-darken(percent)
  if @background
    &:hover
      background: darken(@background, percent)

.test
  background: blue
  hover-darken(50%)

The hierarchy is required to be whitespace indented which makes it easier to identify which parent selectors child selectors belong to.

Not only does Stylus support all the features from Less and Sass, it provides features not found anywhere else:

• You can get properties from parents and pull them into children and/or mixins - if the property isn't found, it will bubble up until it finds a match
• Introspective API, where a CSS block can tell if it’s at root level or not and change its output based on this
• Splats - taking variable amount of arguments in as an array
• Automatically vendor prefixes @keyframes
• Pass a CSS literal block wherever you want
• Convert files to base64

One of Stylus' distinguishing features is transparent mixins: reusuable, possibly dynamic styles that look exactly like native CSS properties. This is particularly useful for using future non-prefixed properties and having them transparently expand to their prefixed counterparts without any special, preprocessor-specific syntax.

Stylus runs on node.js which makes it very easy to integrate into your project if you're using npm.

@extend gives inheritance and unlike for other preprocessors, you can pass any CSS selector, not just classes.

Stylus has clear and detailed error reporting that includes stack traces and line numbers.

Nib is Stylus's answer to Compass, but with the advantage of transparent mixins.

Ride css add dozens of useful mixins to Stylus. Compatible with axis, nib and other mixins libraries.

Roots is a awesome toolkit that contains a CSS library for Stylus that provides the benefits of Nib and more. It is essentially a collection of mixins that add a variety of enhancements to the Stylus workflow.

Stylus can also convert files to base64 which provides the following advantages:

• Easier to maintain
• Gives you the cleanliness of a URL link resource as well the benefits of base64 encoding
• Reducing the number of requests

Functions like max(), min(), sum(), all collour handling functions are all there.

PostCSS is 3-30 times faster than Sass (including libsass), Less, and Stylus

PostCSS allows you to opt-in to the features you need with plugins. This allows you to set it up to behave exactly like Sass, with nesting, mixing, extends, and more. On the other hand, it allows you to use plugins by themselves for things like auto-prefixing, minification, and more. You can even set up your own custom "stack" of plugins to do exactly what you like.

Rather than learn a different syntax, PostCSS allows you to write in pure CSS.

Since it's basically CSS extended through JavaScript it works in the browser directly without the need to compile it beforehand.