I found metro User Interface will suit my website's look. I would like a tiled Dashboard with grouped items like Windows 8 start menu and button style and text style identical to metro user interface. So can I do it or am I restricted use the design in my website?
you can design your website that will run in a web browser. There are many web browsers that people use, and on many operating systems. People will view your website in the manner that suits them, not you.
If they use a windows 8 metro app browser to view your website, your design can be proper metro style. Otherwise it will be a windows 8 style web design in a different setting.
You may want to make an app where you can dictate the environment