Not working with .sass

[fredguth]

Steps to reproduce

1. create-cycle-app rabisco --flavor cycle-scripts-one-fits-all --yarn
2. change styles.scss to styles.sass in webpack.config.js
3. rename src/css/styles.scss to src/css/styles.sass
4. change styles.sass code to

*
  box-sizing: border-box

.double-menu
  $item-size: 6rem
  $item-margin: 0.5rem

  position: absolute
  bottom: 1rem
  left: 1rem

  > .menu-vertical,
  > .menu-horizontal
    position: absolute
    bottom: 0
    left: 0

  > .trigger
    position: relative
    z-index: 2
    display: block

  > .trigger,
  > .menu-vertical > .menu-item,
  > .menu-horizontal > .menu-item
    width: $item-size
    height: $item-size
    padding: $item-margin
    cursor: pointer

6. npm start