hsl(210, 100%, 50%)
The HSL color format is an alternative to the RGB color format. It has three components to it - hue, saturation, and lightness.
The HSL color format is easier to use than the RGB. Since the HSL color format does not require any additional calculations for creating a gradient, it can be used in conjunction with other formats such as RGB or hexadecimal.
Throughout history, there have been many different ways of representing colors such as using words or using digits from 0-255. In contrast to these methods, the HSL color format has its values of Hues, in degrees, while its Saturation and Lightness values are in percentages.