1. Daily UI

Every challenge is delivered to your mail and you can complete your challenges anytime as you may want.

2. 100DaysCSS Challenge

Focused to drill down on your CSS skills. You will rise up to be a CSS Guru after taking up this challenge.

#100DaysChallenge is a very popular tag on Twitter. You can document your journey there and gain a lot along with the community there.

3. Dribble

Features one of the greatest collections of designs over the internet. You can leverage these already built designs to code their clones.

In dribble, you can pick any design you may want to code and start making it.

4. CodePen Challenges

Codepen also offers a lot of challenges that help you to level up your skills by building things. They have a monthly theme and each week you will be prompted with a new challenge.

There is a huge number of participants and a majority of them share their codepen with others. So, you’ll never feel like you are doing it alone. The community is there to lift you up.

5. Frontend Mentor

Solve real-world HTML, CSS and JavaScript challenges whilst working to professional designs. Join 303,212 developers building projects, reviewing code, and helping each other get better.