RGB/RGBa in Sass

rgba.scss

// Declare the color as RGB; SASS will treat this as hex
$green: rgb(27,224,63);
// Declare an alpha
$alpha: .5;
// Declare another color variable as a color with an alpha
$greenAlpha: rgba($green, $alpha);

body {
  /* As RGB (which SASS actually ouputs as HEX) */
  background: $green;
  /* With RGBa syntax */
  background: rgba($green, $alpha);
  /* Or as a simple variable with RGBa */
  background: $greenAlpha;
}