In other words, you cannot have two heading levels on the same line, and there will always be space above and below the heading. This also means that you cannot use heading containers to boldface or change the size of text in the middle of a paragraph. This also means that you cannot use heading containers to boldface or change the size of text in the middle of a paragraph. The paragraph will be split with the heading text on its own line between the other pieces of the paragraph. This is both a mistake and a violation of the heading structure.
Many browsers allow the user to set the size of each element, including the headings.
The page designer cannot guarantee that the document will appear exactly as envisioned. The beginning of a normal text paragraph. . . . The beginning of a normal text paragraph. The beginning of a normal text paragraph. . . . The beginning of a normal text paragraph. . . .