Any Exercises For Practicing CSS?

Why not make your own personal website? That'd give you a pretty good opportunity to practice your skills.

Alternatively, you can visit the following website which contains a ton of free HTML & CSS templates:

http://templates.ironmyers.com/

If you click on the "download" link underneath any of those templates, you'll get the HTML and CSS files, as well as any images/other assets that come along with the template. You can then use the HTML and images to try to re-create the look and feel of the website using your newfound CSS skills. Or, if you're feeling creative, do your own redesign.

Nothing cements your knowledge better than applying it to a real-world project. When I was going through many of the treehouse courses, I was immediately applying those skills to my personal blog and a couple other projects that I have been building on the side. When you come across something interesting in one of the videos, pause it and go apply that trick to some project you are working on. As Marc Clinedinst mentioned, building a personal website is a great place to start if you don't have any awesome ideas to build out just yet. Even if it is just a portfolio of cat GIFs, use something on the side to begin playing around with CSS, and slowly build out the complexity as you learn new syntax. The best way I have come to analogize it is: Just like a good carpenter needs a complete set of tools and the skills to wield them, so does a good web design/developer. Each small thing you learn is a new tool you can stick in your tool belt, and one of the best ways to permanently learn these skills by using your creative process to think up a problem and then find your own solution with the tool belt you've been assembling.