Another part of CSSDeck is the Creations gallery (which is what it started with). If you ever made something cool with CSS/JS just submit it and we'll showcase it in the gallery. It's purely for educational and inspiration purposes.
Last but not the least, you can make testcases and share with other people who can help you out solve your coding problems. You can also collaborate with them in realtime and code collaboratively.
Check out the Documentation.