98.css – design system for building faithful recreations of Windows 98 UIs

I think this would be a great reference for teaching introductory UI design; with the 3D-ness you can clearly see the different states that each UI element requires.

I also really like the quotes about each component! Is there an online copy of this Microsoft Windows User Experience manual somewhere?

You can borrow a (badly scanned) copy on archive.org: https://archive.org/details/microsoftwindows00micr_0/page/63...