Spacing between paragraphs doesn't obey style rules

[nms]

Hi folks
I'm a newbie with NOF but understand the basics of CSS and style inheritance. Here's what's happening:
I create a text box and type a few paragraphs. A check of the HTML shows that they're straight <P> blocks, apart from the last which has <p style="margin-bottom: 0px;">. When I preview the page, there are large gaps between the paragraphs. If I set margin-bottom to 5px, the gap is OK.
Obviously, I don't want to edit every paragraph, so I go into the CSS. BODY has margin-bottom set to 5px by default, and P is undefined, so inherits it. I set the P margin-bottom to 5, but still get large gaps between <P> paragraphs. I've used the "clear" button" to remove my formatting in the paragraph text, and checked the HTML, but can't seem to get the look I want, unless I set it explicitly on each paragraph.
There's no indication that my paragraphs are a sub-style with a different setting, so what's going on?
Any ideas?

[antonsvideo]

very simple
https://www.videoproductions.com.au/...bove-below.png

[T84a]

This does not work for me. Anything else to look for?

[franko]

Where are you setting/amending your style definitions? You should set all styles in Styles->Manage Styles. I always do this before starting on a site.

[antonsvideo]

This does not work for me. Anything else to look for?

works perfect here, can you explain which part does not work? to test, after making settings I mentioned, create a new text box and type some text, does it work?

maybe you already manually formatted the text, if so, select all and clear any existing formatting