Jim van Dam (1) [Avatar] Offline
IE 9/10/11 do not make semantic elements display as block making some of your examples in the book look awkward in IE. Maybe add display: block in used css for these examples or reference to tools like modernizr earlier in the book?

Keith J Grant (21) [Avatar] Offline
Thanks for the heads up. It looks IE has a bug with <main>, though it does support all the other semantic elements from IE9 up. I'll add the fix.