new way

gistfile1.txt

// variables.scss

$color: "red"

// componentA.scss

@import "variables.scss" // needs this line or it wont find $color 

.componentA {
  color: $color;
}

// componentB.scss

@import "variables.scss"

.componentB {
  color: $color;
}

// manifest.scss

@import componentA
@import componentB

// ComponentA.js

import 'componentA.scss' // has only componentA.scss embedded