Unfortunately, HTML5 is not supported by older browsers and default styling for these new elements is not in place across all browser platforms. In order to add some visual consistency across browsers we need to declare some default css to get us moving in the right direction.

Add these styles to the beginning of your css file

[crayon]
main, article, aside, details, figcaption, figure, footer, header, hgroup, nav, section {
display: block;
}
[/crayon]