Which format to use where
HEX is the compact default in CSS and design tools. RGB is useful when you need alpha transparency (rgba) or are manipulating channels in code. HSL is the most human-friendly for adjustments: change lightness for hover states and hue for theme variants without recalculating everything.
Accepted inputs
3- and 6-digit hex with or without #, rgb(r, g, b) with values 0–255, and hsl(h, s%, l%) with hue 0–360. The picker always produces a 6-digit hex.