Using the CSS below in either a Custom Style or in the Style Preferences "Additional CSS" field in Marked 2 will add nested numbers before each heading in your document (e.g. 1, 1.1, 1.2, 1.2.1):

You can use Marked's keyword highlighting features to highlight sentences exceeding a certain number of words. This can be modified to work with other requirements as well, if you know a bit about regular expressions.

In fairly rare circumstances you may want to show the fences of a fenced code block. Normally this could be accomplished in Markdown by indenting the fenced code, forcing an indented "verbatim" block containing the fenced code block, which would then be unprocessed. Marked handles fenced code differently (as part of its ability to work with multiple syntax options), so to accomplish this you need to use a double fence. Because you can use any number of backticks or tildes to fence a code block (as long as the opening and closing count match, you can just use two different length fences. For example