HSL also allows for an opacity value. HSLA is similar to HSL, just in additional it accepts the fourth opacity value.
HSLA(hue, saturation, lightness, opacity)
| hue | in degrees from 0 to 359. examples: 0 = red, 60 = yellow, 120 = green, 180 = cyan, 240 = blue, and 300 = magenta. You can use any value in between. |
| saturation | as a percentage. 100% is the norm for saturation. Saturation of 100% will be the full hue, and saturation of 0 will give you a shade of gray—essentially causing the hue value to be ignored. |
| lightness | A percentage for lightness, with 50% being the norm. Lightness of 100% will be white, 50% will be the actual hue, and 0% will be black. |
| opacity | value between 0 and 1 |
snippet
hsla(300, 100%, 50%, 0.5)
It is magenta with full saturation and normal lightness, which is 50% opaque.
snippet
hsla(0,100%,13%,1.0)
