This plugin creates a <span> for every heading h2, h3, h4 … as you wish <h2><span id="created-from-heading">Created From Heading</span></h2>
and a content table entry like <a href="#created-from-heading">Created From Heading</a>
No CSS-trick worked.
Until I found out, there is a checkbox in the backend “Enable smooth scroll effect”
Only when this is checked, you find in the advanced option:
“Smooth scroll top offset“