In the mid 2000s, as internet and web browsers soared in popularity, personalization and customization was the name of the game. Starting with Firefox's userChrome.css and userContent.css, the ability to write custom stylesheets for your browser interface and even web pages themselves started popping up. Chrome and Safari followed Firefox with their own related features in the late 2000s as well. Userstyles, as they are now more commonly referred to, were made even more popular by the Stylish browser extension, which brought further features and customizability for userstyles across all browsers. Want to change how all the scroll bars look? Write a userstyle. Don't like the way that button looks on a specific website? Write a userstyle!