Notice that the heading is in a larger type size. We have not specified the size, so a default size is used.
If you look at the source code, you will see a lot of strange stuff at the beginning. If you are working locally, ignore all that and just put in the html tag. If you want your code to validate as legal XHTML, then just copy these lines in. We're not even going to try to explain them. You will always find them there, because we have validated all examples and we want to be able to revalidate easily after making any changes.