If you need help with styling your website or your reddit, or want to share a neat trick you cooked up, it's welcome here! For reddit-specific questions, you may also try /r/csshelp and /r/reddithax, but if a post is appropriate there, it's appropriate here, too. Here in /r/css, you've got a place on reddit to talk about CSS, whether you're new to CSS and want to learn, or a pro wanting to discuss the engineering and usability reasons that all modern browsers ignore
CSS, short for Cascading Style Sheets, is used almost universally across the web to affect the design and appearance of every website you visit.