https://wiki.selfhtml.org/wiki/Grafik/Farbkonzept/Farbenlehre
https://snook.ca/technical/colour_contrast/colour.html#fg=000000,bg=2DC3E5
https://webaim.org/resources/contrastchecker/
https://www.w3.org/Translations/WCAG20-de/
Farben umrechnen https://www.webfx.com/web-design/hex-to-rgb/
Farben benennen http://html-color.org/names http://html-color.org/names