colourspace: Convert from One Colour Space to Another, Print a Ready-to-Paste Modern 'CSS' Syntax

Provides a comprehensive 'API' for colour conversion between popular colour spaces ('RGB', 'HSL', 'OKLab', 'OKLch', 'hex', and named colours) along with clean, modern 'CSS' Color Level 4 syntax output. Integrates seamlessly into 'Shiny' and 'Quarto' workflows. Includes nearest colour name lookup powered by a curated database of over 30,000 colour names. 'OKLab'/'OKLCh' colour spaces are described in Ottosson (2020) . 'CSS' Color Level 4 syntax follows the W3C specification .