Can I learn CSS without knowing HTML?
Unfortunately, you can't really learn CSS without knowing HTML. The two go hand-in hand. In fact, it is recommend that you learn HTML and CSS at the same time, especially because HTML is much more interesting when you apply CSS to it.
What is front-end development?
Which CSS framework should I learn?
Bootstrap is one of the most popular CSS frameworks available today. With Bootstrap, you can learn how to design a website in just a few hours, even as a beginner. Because it is so common, Bootstrap is a great framework to learn. Materialize CSS is also one of the easier frameworks to learn, however it is not as visually pleasing as some of the other frameworks.