All the pages in this whole Borders tutorial have a div in the head tag that is included inside a table cell which has border="0", for centering on the screen. The border-top-left-radius property allows you to add a rounded border to the top-left corner. Similarly, adding the border-top-right-radius, the border-bottom-left-radius, and the border-bottom-right-radius will allow you a border with all four corners rounded and with different radii like the ones you see here. Radii are expressed in "em" rather than pixels.
For this page:
Remember to include a DOCTYPE tag, such as <!DOCTYPE html>
Border Styles Introduction ~ 2 ~ 3