Syncfusion have another of their free ‘Succinctly’ E-book series, this time on CSS3. https://www.syncfusion.com/... As noted before, you need to register to download these books but there’s no other commitment and several other benefits from registering, not least their Metro Studio icon tool ......
Simplilearn have an excellent list of CSS3 resources which covers just about every question you’d want to ask.
http://www.simplilearn.com/css3-resources-ultimate-list-article
Definitely worth book marking.
It’s a great help being able to use fully developed and tested CSS grid packages but sometimes they are total overkill for a simple project. Even Skeleton, one of the easiest to use, can be too prescriptive. Chris Nager has created what he calls ‘ungrid’ and describes it as the simplest responsive grid system. The basic minified CSS file is a mere 97 bytes. The caveat? It uses CSS tables which need IE8 or greater and early versions of some other browsers need prefixes adding. Definitely worth looking ......