Developers often use before and after pseudo-elements (generated content) for the styling of elements in websites. With a few lines of extra CSS, it is possible to include icons, images, or even add text without adjusting the HTML.
Complete guide, summarized WebGL tutorial, with tiny interactive demos in each chapter.
How to Make One of Those Fancy Scrolling Animations Used on Apple Product Pages?
To see and install these optional fonts, open the FontBook application and switch to “All Fonts”.