Subscribe to The Chicago Manual of Style Online
Q. In typing a single quotation mark within a double quotation mark, does one add a space for clarity, as in “ ‘, or are they printed without a space, as in “‘?
A. Typesetting software often adds a hair space automatically, so don’t type in an extra space. If you want to be sure of getting a thin space, mark on the manuscript “thin#” or “hr#.” In works published online, a nonbreaking space can be used and will enhance legibility.