styled-components/src/constructors/css.js

**This is a work in progress** based off of [this demo](https://github.com/geelen/css-components-demo).

// @flow
import interleave from '../utils/interleave'
import flatten from '../utils/flatten'
import type { Interpolation, RuleSet } from '../types'

export default (strings: Array<string>, ...interpolations: Array<Interpolation>): RuleSet => (
  flatten(interleave(strings, interpolations))
)