old way

gistfile1.txt

// variables.scss

$color: "red"

// componentA.scss

.componentA {
  color: $color;
}

// componentB.scss

.componentB {
  color: $color;
}

// manifest.scss

@import variables
@import componentA
@import componentB

// ComponentA.js

import 'manifest.scss' // has both componentA and componentB styles embedded in it