CSS 3 is one of the best technologies to come from the #WWW movement. It provides clean separation of semantic layout (#HTML5) and its presentation (CSS 3), allowing fine tuning of the presentation on different screen sizes for a fully responsive experience. With the addition of flexboxes, CSS variables, transitions and animations it is even more powerful than before. In previous versions preprocessors were required to manage complex layouts, but with the latest CSS 3, CSS variables can handle everything for you. This reduces complexity, learning curves, setup and deployment time. I like to use it with #Visualstudiocode and in conjunction with #Javascript when I need the additional power of a programming language. It's worth taking the time to really get to know CSS 3. If you are starting out I recommend starting here https://www.w3schools.com/css/.