Write something, and format it as you prefer (font, font size, line spacing, etc.). Highlight your formatted text, and then click “Format”, then “Paragraph Styles”, “Normal Text”, and then finally “Update normal text to match”. you must have the text that you formatted to your likin ghighlighted while doing this. You then must re-open format, and paragraph styles, but this time hit “Options” and then hit “Save as new defualt styles”. You should get a little message that pops down from the top of the doc that says something like “new style updated” and that should be it.

That’s what worked for me,hope that solves your problem.