Dynamically load stylesheets in Firefox from plaintext files in your profile. superUserContent is a simple Firefox plugin that creates a new directory in your profile's chrome directory called userContent.css.d. You can use this directory as a runtime path for css stylesheets. superUserContent will apply any stylesheets it finds in this directory to pages when they load. Changes to css files in userContent.css.d will take effect when the page refreshes Make rapid prototypes or try out new changes without busting your cache Use your own editor and CLI tools to maintain themes superUserContent is for developers who want an easy way to change the look and feel of the sites they frequently visit using their own text editor and CLI tools. superUserContent is a great tool for theme designers who want to share their customizations on sites like userstyles.org so they can be used easily by casual browser users with plugins like Stylish.