HTML and CSS are actually surprisingly large topics, who would have thought? If you've made it this far, though, you're more than well on your way to front end development magic. You should be significantly more comfortable breaking down a webpage into its component pieces and then coding them with HTML and CSS. You have the tools necessary to identify an effective visual layout and then bring it to fruition.
There are still plenty of ways you can make your workflow better or improve your knowledge of best practices (so don't stop learning!), but you've got everything you need to build beautiful websites.
This section contains helpful links to other content. It isn't required, so consider it supplemental for if you need to dive deeper into something.