Remove macro from sc import preset

[ben-rogerson]

This patch adjusts the css import to remove the macro.

This is due to an error that started being thrown in CRA when using preset: "styled-components":

Attempted import error: 'css' is not exported from 'styled-components/macro' (imported as '_css').

Old:

import { css } from 'styled-components/macro'

New:

import { css } from 'styled-components'

Reference #264