Anchor for headlines

I have a beginner question. It is not hugo specific. I use a fixed header.
When I click on a link the headline from the link is under the fixed header.
The header should be 100px below the headline.

Here some lines from my css

.anchor {
  position: relative;
}
.anchor h1 h2 h3 {
  position: absolute;
  top: -100px;
}

Here some line from the content

{{% divmd class="anchor" %}}
# Manuals

---

## Styleguides

is, feugiat a, tellus. Phasellus viverra nulla 
ut metus varius laoreet. Quisque rutrum. Aenean imp

### Coding

is, feugiat a, tellus. Phasellus viverra nulla 
ut metus varius laoreet. Quisque rutrum. Aenean imp
{{% /divmd %}}

Here the shortcode

<div class="{{ with .Get "class"}}{{.}}{{end}}">
  {{ .Inner }}
</div>

Here the links

Sorry @Joerg, we don’t answer general HTML/CSS questions here. Near the end of the Requesting Help post there are some links to places to find web resources. :slight_smile: