1. CSS3 Colors

    Method of describing colors using Hue, Saturation and Lightness (hsl()) rather than just RGB, as well as allowing alpha-transparency with rgba() and hsla().

  2. types: <color>: `rgba()` (rgb color model)

  3. types: <color>: `rgba()` (rgb color model): float values in parameters

  4. types: <color>: `rgba()` (rgb color model): space-separated parameters