I'm breaking out an existing article into a few different sections, and each section has a header (Header 3), and they look right in the editor view, but when published, they appear to be the same size as regular paragraphs.
Editor view on the left, published view on the right. Look at the headers “Organization” and “Permissions”.

Follow-up: I did go in and change the *size* of the text from “Default” to “Large” and now it looks as I expected it to. I would've thought that using a “Header” would have automatically set a larger size - as it appeared in the editor mode.
