tombenner/nui

NUI is an Objective-C library for iOS apps that lets you control the visual appearance of your entire app through a single stylesheet file, working in a similar way to how CSS stylesheets work on websites. On the web, CSS lets designers write rules like "all buttons should have a blue background and white text" in one place, and those rules apply everywhere automatically. NUI brings that same idea to native iOS development. Without NUI, changing visual styles in an iOS app typically means hunting through code files and Apple's documentation, figuring out which specific property on which specific class controls the appearance you want to change, then repeating that process for every screen. With NUI, you write rules in a stylesheet file using a CSS-like syntax, and they apply to all matching UI elements across the app without any additional code changes. The stylesheet supports variables, so you can define a primary color or font once at the top of the file and reference it throughout all your rules. This mirrors the approach of CSS preprocessors like Sass. You can also create custom style classes for elements that need a distinct look, and have those classes inherit rules from other classes. Styles can even be changed while the app is running, which makes it much faster to iterate on visual design. Installing NUI is a matter of adding a CocoaPods entry and adding one line to the app's startup code. After that, you edit the stylesheet file directly, and changes are picked up the next time the app runs. The library also supports Swift projects through a bridging header or native import. NUI applies styles globally to all standard iOS components: buttons, navigation bars, labels, table views, text fields, sliders, switches, and more. If a specific third-party component should not be affected, you can exclude it by name in the stylesheet.