Lately I'm confronted with many spam emails which has 'good text' in it but this text is not really shown because it has strange margin values like margin-bottom: 223328553564px; (and display: none and/or opacity: 0) in it. Instead a big image is shown with xxx spam.

html code of such emails looks more or less always like this:

Which SpamAssassin rule could block such emails (with not shown text because of high margins,...)