This ends up being really useful for building application UIs because you spend less time undoing user-agent styles, but when you really are just trying to style some content that came from a rich-text editor in a CMS or a markdown file, it can be surprising and unintuitive.
What if we stack headings?
We should make sure that looks good, too.
Sometimes you have headings directly underneath each other. In those cases you often have to undo the top margin on the second heading because it usually looks better for the headings to be closer together than a paragraph followed by a heading should be.
