If you started your journey as a web developer, chances are the very first concepts you heard about were HTML and CSS. Perhaps you have already mastered these two skills and started building websites. If you have, I have good news for you: yes, these two skills are genuinely enough to build a website. But they are not sufficient. It is possible to build any site using HTML and CSS, and the professional frameworks and libraries we will look at shortly are built on top of HTML and CSS foundatio...