An extensive CSS reference offering way more content than MDN.

Interactive browser support tables for CSS (and HTML5).

This screencast series will teach you the basics of CSS in about one hour.

This article explains what the cascade is and how this affects you.

Understanding specificity and inheritance is important to master CSS. This article will help.

An article explaining the foundation of layout on the web.; Also have a look at the detailed information about the…

Extensive information about all aspects of responsive design to make sites that look great and work well for everyone.

Overview covering absolute and relative units.

Imparts the basics and shows some nifty use-cases.

An introduction to the very basic CSS selectors you need to know.

Level up your knowledge. From attribute selectors to CSS3 pseudo classes.

Learn how to use CSS selectors with this fun little game.

A short introduction to CSS variables.

Describes the advantages of locally scoped CSS variables.

Patterns and anti-patterns for using CSS variables.

In depth article going beyond the basics of CSS Variables using real-world examples.

Mindblowing talk about the possibilities of the combination of CSS variables and functional reactive programming in…

Learn about CSS layout techniques in 5 chapters.

Jen Simmons video series about the new CSS Layout possibilities.

Introduction of a new layout system encompassing Flexbox, CSS Grid and the Box Alignment Module.

In depth information about how to use (and clear) floats.

A closer look at a few little-known things related to the CSS positioning layout method.

Shows in which cases it makes sense to use the display property inline-block for layouting.

All you need to know about Flexbox on one page.

Play with Flexbox examples on CodePen.

A tower defense game in the browser to learn about Flexbox with fun.

Learn all the basics of Flexbox with a fun game involving frogs and lily pads.

Community-curated list of flexbox issues and cross-browser workarounds for them.

A training course driven by a storyline where you use Flexbox and a crossbow to hunt zombies.

A simple, free 20 video course that will help you master CSS Flexbox!

All you need to know about CSS Grid Layout on one page.

Besides examples of how to use Grid, this site also has additional useful learning resources.

Talk about the new layout possibilities CSS Grid is offering.

Lovely game where you write CSS code to grow your carrot garden.

Community-curated list of Grid interop issues and workarounds for them.

Learn CSS grid layout by mastering an adventure game.

Learn CSS grid with Wes Bos - Free 4 hours video course, 25 Videos.

An introduction to CSS transitions and CSS (2D) transforms.

Also addressing advanced topics from chaining and events to hardware acceleration and animation functions.

Multi page tutorial with examples like card flip and carousel effects.

Imparts the concepts of CSS animations with keyframes.

Nice little page demonstrating which CSS properties are animatable.