There is no HTML and CSS for an InDesign file.
Once you export the file you can check it out in Dreamweaver.
I think I understand now: The HTML anf CSS are added as part of the export process? Is this correct?
When you export either an EPUB or HTML file, the paragraph styles, character styles, object styles, etc. are "translated" into HTML and CSS. However, it's an imperfect process because of the differences between the two types of styling.