CSS

CSS is the primary method of styling HTML elements. It’s what makes a boring page look visually stunning. 

Cross-browser compatibility is an issue with CSS — so it’s important that you validate your code, know all of the selectors, properties and values you can work with, and consider the browsers’ needs. If you’re thinking of expanding your knowledge of CSS for future-standards-compliant browsers like Chrome, Safari and Firefox, now is a good time to learn about how you can progressively enhance your web designs with CSS3.