Read this short and concise CSS Guide by @mdo.

Can I use to lookup feature’s browser support.

Trustworthy search results coming from:

• https://css-tricks.com/
• https://developer.mozilla.org/
• https://css-irl.info/

Follow people who excels at CSS (Why?):

• Brad Frost
• Chris Coyier
• CSS Tricks
• CSS Working Group
• Geoff Graham
• Jen Simmons
• Lynn Fisher
• Mark Otto
• Michelle Barker
• Miriam Suzanne
• Rachel Andrew
• Robin Rendle
• Sarah Drasner

I like to watch videos from:

• Layout Land
• Mozilla Developer
• Google Chrome Developers

Clear doubts at how popular framework do it:

• PostCSS
• Pure.css
• Primer
• Tachyons