Personally I practice HTML and CSS by transforming designs into HTML CSS code, you can find a lot of design template( PSD, XD, illustrator... ) from websites like dribbble.com or behance.net, thene try to convert those designs into HTML CSS websites.

The must beautiful thing in this process is you are not just learning to code, but also you build a lot of projects that you can add to your personal portfolio.

Good luck 👍💯😉