rgba()
The rgba() functional notation expresses a color according to its red, green, and blue components. An optional alpha component represents the color's transparency.
Note: CSS Colors Level 4 allows for space-separated in addition to comma-separated values.
Syntax
rgba(255, 255, 255) /* white */
rgba(255, 255, 255, .5) /* white with 50% opacity */
rgba(255 255 255 / 0.5); /* CSS Colors 4 space-separated values */
Values
- Functional notation: 
rgba(R, G, B[, A]) - 
    
R(red),G(green), andB(blue) can be either<number>s or<percentage>s, where the number255corresponds to100%.A(alpha) can be a<number>between0and1, or a<percentage>, where the number1corresponds to100%(full opacity). - Functional notation: 
rgba(R G B[ / A]) - 
    
CSS Colors Level 4 adds support for space-separated values in the functional notation.
 
Browser compatibility
BCD tables only load in the browser
Space-separated values
BCD tables only load in the browser