HEXkoodi

HEXkoodi, or hexadecimal color code, is a compact representation of color used in digital media, web design, and software. A typical hex code starts with a hash symbol (#) followed by six hexadecimal digits. The first two digits specify red, the next two green, and the last two blue. Each pair ranges from 00 to FF, corresponding to 0 to 255 intensity. For example, #1E90FF encodes a medium blue.

A shorter form exists in many applications: #RGB expands to #RRGGBB by duplicating each digit (for instance, #3F3 becomes #33FF33). In modern CSS, an eight-digit variant is also used to include alpha transparency, written as #RRGGBBAA in some environments, where AA determines opacity.

HEXkoodis are case-insensitive in practice, meaning #1e90ff and #1E90FF denote the same color. They are widely supported across programming languages, graphics tools, and web technologies. Hex codes are often generated by color pickers in editors or design software and can be converted to other color models such as RGB, HSL, or CMYK.

Usage and considerations: hex colors are essential in web styling (CSS), user interfaces, and graphic design. They enable precise color matching but require attention to accessibility, as insufficient contrast with background elements can impede readability. Designers often test hex color combinations against WCAG contrast guidelines to ensure legibility.

See also: color models (RGB, HSL, CMYK), CSS color specification, color accessibility.