1. Frontend Mentor

Frontend Mentor is a platform that offers front-end challenges such as professional web designs. These allow you to practice building websites in a realistic workflow. Taking these challenges will help you improve your skills, gain experience creating websites, and build up an incredible project portfolio. It also has a huge developer community, so it's a wonderful way to meet other developers!

2. Daily UI

Daily UI is a design challenge to inspire and challenge designers around the world. You'll design 100 different user interface elements for mobile and web. This project was built to provide a fun engaging way to improve your skills as a designer, earn rewards, and get feedback from others.

3. 100DaysCSS Challenge

100DaysCSS challenge is designed to help you improve your CSS abilities. After completing this challenge, you will be a CSS pro.

4. Codewell

Codewell is used to improve your HTML and CSS skills by practicing on real design templates.
With Codewell, you can browse high quality Figma templates that you can use to sharpen your HTML and CSS skills.

5. CSSBattle

CSSBattle is a CSS Code Golfing game that can be played online. Players from all around the world compete to see who can visually reproduce "Targets" with the shortest amount of CSS code and get to the top of the scoreboard.

So those are the top five websites I use to improve my frontend development skills, please leave yours in the comments, and if you want more posts like this, please follow me.