CSS3 Colors

CSS supports color names, hexadecimal and RGB colors.
In addition, CSS3 also introduces:

• RGBA colors
• HSL colors
• HSLA colors
• opacity

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Browser Support

The numbers in the table specify the first browser version that fully supports CSS3 color values/property.

Property
RGBA, HSL, and HSLA	4.0	9.0	3.0	3.1	10.1
opacity	4.0	9.0	2.0	3.1	10.1

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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).

rgba(255, 0, 0, 0.2);

rgba(255, 0, 0, 0.4);

rgba(255, 0, 0, 0.6);

rgba(255, 0, 0, 0.8);

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 */

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HSL Colors

HSL stands for Hue, Saturation and Lightness.
An HSL color value is specified with: hsl(hue, saturation, lightness).

1. Hue is a degree on the color wheel (from 0 to 360):
   • 0 (or 360) is red
   • 120 is green
   • 240 is blue
2. Saturation is a percentage value: 100% is the full color.
3. Lightness is also a percentage; 0% is dark (black) and 100% is white.

hsl(0, 100%, 30%);

hsl(0, 100%, 50%);

hsl(0, 100%, 70%);

hsl(0, 100%, 90%);

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 */

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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).

hsla(0, 100%, 30%, 0.3);

hsla(0, 100%, 50%, 0.3);

hsla(0, 100%, 70%, 0.3);

hsla(0, 100%, 90%, 0.3);

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 */

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Opacity

The CSS3 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).

rgb(255, 0, 0);opacity:0.2;

rgb(255, 0, 0);opacity:0.4;

rgb(255, 0, 0);opacity:0.6;

rgb(255, 0, 0);opacity:0.8;

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 */

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