CSS supports 140+ color names, HEX values, RGB values, RGBA values, HSL values, HSLA values, and opacity.
RGBA Colors #
RGBA color values are an extension of RGB color values with an alpha channel – which specifies the opacity for a color.
An RGBA color value is specified with: rgba(red, green, blue, alpha). The alpha parameter is a number between 0.0 (fully transparent) and 1.0 (fully opaque).
The following example defines different RGBA colors:
Example #
#p1 {background-color: rgba(255, 0, 0, 0.3);} /* red with opacity */
#p2 {background-color: rgba(0, 255, 0, 0.3);} /* green with opacity */
#p3 {background-color: rgba(0, 0, 255, 0.3);} /* blue with opacity */ HSL Colors #
HSL stands for Hue, Saturation and Lightness.
An HSL color value is specified with: hsl(hue, saturation, lightness).
- Hue is a degree on the color wheel (from 0 to 360):
- 0 (or 360) is red
- 120 is green
- 240 is blue
- Saturation is a percentage value: 100% is the full color.
- Lightness is also a percentage; 0% is dark (black) and 100% is white.
The following example defines different HSL colors:
Example #
#p1 {background-color: hsl(120, 100%, 50%);} /* green */
#p2 {background-color: hsl(120, 100%, 75%);} /* light green */
#p3 {background-color: hsl(120, 100%, 25%);} /* dark green */
#p4 {background-color: hsl(120, 60%, 70%);} /* pastel green */ HSLA Colors #
HSLA color values are an extension of HSL color values with an alpha channel – which specifies the opacity for a color.
An HSLA color value is specified with: hsla(hue, saturation, lightness, alpha), where the alpha parameter defines the opacity. The alpha parameter is a number between 0.0 (fully transparent) and 1.0 (fully opaque).
The following example defines different HSLA colors:
Example #
#p1 {background-color: hsla(120, 100%, 50%, 0.3);} /* green with opacity */
#p2 {background-color: hsla(120, 100%, 75%, 0.3);} /* light green with opacity */
#p3 {background-color: hsla(120, 100%, 25%, 0.3);} /* dark green with opacity */
#p4 {background-color: hsla(120, 60%, 70%, 0.3);} /* pastel green with opacity */ Opacity #
The CSS opacity property sets the opacity for the whole element (both background color and text will be opaque/transparent).
The opacity property value must be a number between 0.0 (fully transparent) and 1.0 (fully opaque).
Notice that the text above will also be transparent/opaque!
The following example shows different elements with opacity:
Example #
#p1 {background-color:rgb(255,0,0);opacity:0.6;} /* red with opacity */
#p2 {background-color:rgb(0,255,0);opacity:0.6;} /* green with opacity */
#p3 {background-color:rgb(0,0,255);opacity:0.6;} /* blue with opacity */ 
