Windows 8 Metro apps can be made in several ways, including the use of the HTML language. In a new blog post, Microsoft goes over in detail on how Windows 8 app creators can use HTML controls to help make Metro-based apps.
The highly technical post on the official Windows 8 app developer blog uses an example of how to use those HTML controls by focusing on just one of them; the button control which looks like a click friendly UI when used on a standard web page. Microsoft has made some changes to the control so that for Windows 8 Metro apps, the button looks like this:
The blog post states:
You can check out a list of all of the style changes and additions Microsoft has put into the HTML controls at Microsoft's website.
Source: Windows 8 app developer blog | Image via Microsoft