You may confusing html with the way in which something looks but html is the structure and css applies the visuals. Therefore you can style the b and strong to be what you want. You could for example make them italic but only if inside the first child.
Note that the b element is semantically neutral these days but the strong element is a semantic tag (like em) that adds emphasis to the meaning of the text. This has nothing to do with the visual look of course as that is handled by css. Visuals should not be the only method to convey information as screen readers don’t see anything at all.