Web browsers also seem to be using RGB for storing colors internally. You can specify colors in HSL, but retrieved values are only in RGB. E.g. if you write "hsl(100,0%,0%)" in your CSS file then the color will be represented as #000000 in DOM/CSSOM. This is especially annoying when you are trying to implement color picker because information about hue is lost if saturation or lightness are low.