S-heading as h3 without (visually) nested s-section

I want to write a page with multiple paragraphs and nested sections just like in a normal text document. I don’t want every nested section to be in a rounded padded box! Is there no way to make an <s-heading> be a <h3> without a mess of nested <s-section>s? Is there a way to un-style a <s-section>?