https://codepen.io/gblazex/pen/poWJdvZ?editors=1010

https://docs.microsoft.com/en-us/microsoft-edge/devtools-guide-chromium/whats-new/2021/01/devtools#new-color-contrast-calculation---advanced-perceptual-contrast-algorithm-apca


https://github.com/MicrosoftEdge/DevToolsSamples/blob/master/docs/badges/badges-contrast.html

https://bugs.chromium.org/p/chromium/issues/detail?id=1121900

https://bugs.chromium.org/p/chromium/issues/attachmentText?aid=486488

# these have tables
https://w3c.github.io/silver/guidelines/methods/Method-font-characteristic-contrast.html
https://www.w3.org/WAI/GL/WCAG3/2020/methods/font-characteristics-contrast/

https://github.com/Myndex/SAPC-APCA/blob/master/JS/SAPC_0_98G_4g_minimal.js



https://chromium.googlesource.com/devtools/devtools-frontend/+/c88c76b465f2dc8a853fe2a0997ccbfbff0e5bac/front_end/color_picker/ContrastInfo.js