Scrolling to target element hides headings

**This is a Bug Report**

**Problem:**
If you have a narrow enough viewport and then follow a link to a fragment of a documentation page, the heading (or whatever) that the hyperlink represents is fully or partially hidden behind the top nav.

**Proposed Solution:**
Tweak the CSS (Sass) to avoid that snag.

**Additional Information:**
/area web-development

**Screenshots**
The (second) portrait screenshot shows that the heading text “Resizing an in-use PersistentVolumeClaim” isn't shown the way the reader would expect it to be.


Reproduce the issue by opening a documentation fragment link in a narrow viewport, then inspect the Sass styles controlling the top navigation and fragment target positioning. Done means the linked heading remains fully visible below the navigation in the affected portrait layout.

Written by the indexing model from the issue text.