BibTeX Reference for “CSS Color Module Level 3”

@TechReport{0944064,
  author      = "Tantek \c{C}elik and Chris Lilley and David Baron",
  title       = "{CSS} Color Module Level 3",
  month       = aug,
  note        = "https://www.w3.org/TR/2021/REC-css-color-3-20210805/",
  year        = "2021",
  bibsource   = "https://w2.syronex.com/jmr/w3c-biblio",
  type        = "{W3C} Recommendation",
  institution = "W3C",
}