Is it necessary to learn LESS or SASS ?

It's not "necessary", but 90% of the time, it's worth it. *One of the benefits of learning a css preprocessor is that you can use variables, in other words, you won't have to keep track of a specific color's RGB value. *Another benefit is modularity. You can split your css into multiple files and then compile them into a single file, OR You can compile them separately and just import what you need. SCSS ===== $my_color: #9a2d68; .header{ color: $my_color; } You can "Define Once, Use Anywhere"