hey!! i need some help doing CSS!

hello! first, thank you all for the support , myspace 93 is a form of scape for me <3
aaaand i need some help doing CSS , if anyone could help me i would be grateful!!

-Niko-mush <3
https://pbs.twimg.com/tweet_video_thumb/DhC5QGFW4AAaRSO.jpg