HTML and CSS Reference
You can see how Firefox renders this markup in Figure 4-37, with each descendant heading displayed at a
smaller size, even though they're all h1 elements.
Figure 4-37. Firefox displays headings in nested sections at progressively smaller sizes
Figure 4-38 shows the same content rendered by Opera 12. Every h1 is the same size because this
version of Opera doesn't include any special default rules for headings in nested section s. That will
undoubtedly change in a future update to Opera, but the latest version (at the time we write this) still
displays all h1 s at the same size.
Figure 4-38. The same markup rendered by Opera 12, with all the headings at the same size