Microsoft® Manual of Style, Fourth Edition

Periods

Use only one space after a period in both printed and online content.

When a colon introduces a bulleted list, use a period after each list element if each element completes the introduction to the list or if at least one element is a complete sentence. Do not end the entries with periods if they are all short phrases (three words or fewer), even if together with the introduction to the list, they form a complete sentence. For more information, see Lists (Chapter 7).

In general, format periods in the same font style in which the main content is formatted. This is especially important for a period after an element that receives different formatting to avoid the impression that the punctuation is part of the syntax. Examples are commands, ...