[mrmikel]

Wolfie is right. ADE is the basis of many of the reader's software, but it is not implemented the same in most of them. You need to check your work in real devices. They will also reveal things that the PC software will not show like how things look in smaller windows and also in black and white (or don't appear at all like one title that was in orange!)

Embedding a font makes sure what you need will be there. Be sure the font has every letter you need and is open source unless cost is no object. Embedding a font will increase the size of the epub by a megabyte or more, so some attention is needed to make sure it does not cause a problem for your users. It can be a little tricky so, as above, check the epub in devices you anticipate your readers will use.