https://frontendmasters.com/courses/css-layouts/

Starting with the basics of CSS and HTML, you'll progress through creating responsive designs for mobile, tablet, and desktop layouts. You'll learn to code complex layouts with CSS Grid and Flexbox and tackle real-world exercises like styling buttons, audio players, hamburger menus, and lists. You'll explore concepts like rem and em units, custom fonts, responsive images, and the picture element. By the end of the course, you'll have built three variations of a website, each increasing in complexity!