<html> <head> <style> h3 { border: 2px solid red; padding: 2px; } </style> </head> <body> In this sample, the H3s should not be nested. While WinIE does allow the nesting, Firefox does not. We have chosen to match Firefox, since we size H3s based off the current font size, and therefore nesting would lead to ever-increasing font sizes. <h3><i>One<h3><i>Two<h3><i>Three<h3><i>Four