Don’t expect to get what you want using those attributes
https://developer.mozilla.org/en-US/docs/Web/HTML/Element/body
bottommargin
The margin of the bottom of the body. This method is non-conforming, use CSS margin-bottom property on the element instead.
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topmargin
The margin of the top of the body. This method is non-conforming, use CSS margin-top property on the element instead.