How do I decorate this fawking siteee

click "Edit your profile" and there should be a section on the bottom where you can put CSS code. look up tutorials on CSS. i like to use w3schools as a reference, it's also a good place to start. the inspect element tool in your browser is really helpful, you can use it to play around and see your changes in real time, or use it to see what other people's CSS code looks like.