> Commas and periods that are part of the overall sentence go inside the quotation marks, even though they aren’t part of the original quotation.
I firmly refuse to go along with this nonsense.
http://www.thepunctuationguide.com/em-dash.html
> The em dash is typically used without spaces on either side, and that is the style used in this guide. Most newspapers, however, set the em dash off with a single space on each side.
Isn't this is US versus Britain, not "newspapers" versus "typical use"? And AFAIK it's not a "single space": it's ideally a half-space (in US style). The problem with no space is that your eyes can't easily disambiguate it from a hyphenated single word.