CSS is one of the fundamental pillars of web development and design. While CSS started as something that can change the style of a web page, every CSS specification iteration now brings more to the table, precisely when it comes to cross browser compatibility.
Today, CSS is more than just “background-colour” and tag specifications that made initial web development days a lot of fun. CSS has become a helping tool in bringing out mobile-first design and responsive web design in web applications without making too much effort.