It used to be a pain in the bum to create Office add-ins that fit into the theme of Microsoft's productivity software suite. The company has remedied this problem by releasing its Office User-Interface Fabric on GitHub for developers.
With Office UI Fabric, developers can now apply simple CSS styles to make it look more like Office, with the same typography, colour, icons, animations and responsive grid layouts. There are also reusable components like input, layout, navighation and variety of content.
Explains Microsoft's Office Blog: "You will start to see the add-ins in the Office Store updated to use Office UI Fabric, which will increase the consistency of add-ins you use to increase your productivity day-to-day."
Currently, Office add-ins are only compatible with Windows desktops, web browsers, Mac desktops and iOS on iPads.
You can download the Office UI Fabric over at GitHub.
[Via Microsoft Office Blogs]