HTML & CSS are the building blocks of web development and the easiest languages to learn. You can learn the fundamentals of HTML & CSS in a day but to master them, you have to dedicate a few hours daily. It took me a week to fully understand the basics of it. I did 15 projects to get a firm grasp on concepts like Positions, DOM, and Flexbox and I also learned Figma during the process.
I started by reading documentation and watching some videos on Youtube. I joined Ineuron's Full Stack Javascript Web Developer course and it made learning difficult concepts much easier. I started working on the assignments and I had to put in around 7 to 8 hours daily. Over time, I understood flexbox, positioning, margin, and padding, and built complex websites. You can refer to my Portfolio to check my projects.
Practicing more and more made me understand and connect the dots more easily. Pure HTML & CSS can help to get more control over your page than using frameworks and hence they're the basics to master Web Development.
These are my favorite projects: