$height_auto: auto !default;
$height_xs: 320px !default;
$height_sm: 480px !default;
$height_md: 768px !default;
$height_lg: 1024px !default;
$height_xl: 1280px !default;
$height_2xl: 1440px !default;
$height_3xl: 1920px !default;
$heights: (
  height_auto: $height_auto,
  height_xs: $height_xs,
  height_sm: $height_sm,
  height_md: $height_md,
  height_lg: $height_lg,
  height_xl: $height_xl,
  height_xxl: $height_2xl,
  height_xxxl: $height_3xl
);