Web Colors (Wikipedia)
Wikipedia’s article on web colors. Covers hex triplet notation, the 16 basic and ~140 extended HTML/CSS named colors (derived from X11), CSS color functional syntax (RGB, RGBA, HSL, HSLA, HWB), CSS Color Level 4/5 features (wider gamuts, OKLab, color-mix()), the 216-color web-safe palette (mid-1990s, now obsolete), and accessibility guidance on specifying both foreground/background colors and WCAG contrast ratios.
License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/
Media: Five diagrams/tables (basic HTML colors, X11 color chart, SVG 1.1 named colors, 216-color web-safe table, 22-color “safest” table) — all on Wikimedia Commons; not downloaded, consistent with all Wikipedia ingestions.
Key points
- HSL (hue/saturation/lightness) as a designer-intuitive color model, distinct from RGB but mapped to the same sRGB gamut.
- sRGB as the web’s baseline color space — the gamut against which contrast ratios are calculated.
- Web-safe colors: a now-obsolete mid-1990s constraint (a 216-color palette adopted to avoid dithering on 256-color displays).
- Always specify both foreground and background colors together, to avoid browser-theme combination failures.
- WCAG 1.4.3 contrast ratios: 4.5:1 (AA, normal text), 3:1 (AA, large text), 7:1 (AAA) — with the nuance that maximum AAA contrast is not universally optimal for dyslexic readers.