http://cssnext.io/features/#color-function
справочник https://cssreference.io/flexbox/ => интерактив по флексам http://flexbox.help/ => для продакшена https://dmitriy-8-kireev.github.io/flexboxgrid2/docs/
справочники https://gridbyexample.com/learn/ и https://css-tricks.com/snippets/css/complete-guide-gr.. => интерактив по Гридам http://yui.github.io/gridbuilder/ и https://codepen.io/anthonydugois/pen/RpYBmy
https://habr.com/post/305900/ и https://learn.javascript.ru/es-modern
https://github.com/areai51/yarn-cheatsheet
https://github.com/UsulPro/js-stack-from-scratch-v1-rus
Список рекомендаций по вёрстке БЭМ