Base16

Base16 refers to the base-16 numeral system, a positional numeral system that uses sixteen distinct symbols. In most conventions, the digits 0 through 9 represent values zero to nine, and the letters A through F (or a–f) represent ten to fifteen. Each place value corresponds to a power of sixteen; thus one hex digit encodes four binary bits, or a nibble, making hexadecimal convenient for representing byte-oriented data. Hex notation is common in computing for memory addresses, machine code, and color values. In many contexts, hexadecimal numbers are prefixed with 0x or suffixed with h and written in uppercase or lowercase.

Base16 is also the name of a design project that provides a standardized set of sixteen colors and a framework for creating color themes. The Base16 themes define a palette of base00 through base0F, with each color assigned a typical role (background, foreground, comments, strings, keywords, etc.). Themes built on these palettes aim for consistency across editors, terminals, and IDEs, and are widely ported to many tools.

The Base16 approach separates color choices from the application logic, allowing a single palette to be used by different software. The project supplies reference palettes and guidelines to generate theme files in multiple formats, such as CSS, JSON, Vim, Emacs, and others. While the base16 color sets are designed for readability and contrast, users can select a theme that suits their preferences and lighting conditions.