Third level header
h3
The h3 element is a header identifying the following paragraphs as providing details or an in-depth exploration of a specific sub-topic.
h3 elements should be used when the detailed paragraphs are lengthy enough to warrant inclusion in the article's outline.
The elements h1 through h6 form a structural hierarchy for an article and may be used to build a table of contents.
Example
h1 Ordering and Seqeuncing in Formal Compositions
p ...
h2 Outlines
p ...
h3 Alphanumeric Outlines
p An alphanumeric outline includes a prefix at the beginning of
each topic as a reference aid. The prefix is in the form of
Roman numerals for the top level, upper-case letters for the
next level, Arabic numerals for the next level, and then
lowercase letters for the next level.
h3 Decimal Outlines
p The decimal outline format has the advantage of showing how every
item at every level relates to the whole.
h3 Bare Outlines
p Bare outlines include no prefixes.