Bug: heading anchor overlapped by fixded header

[llighter]

Describe the bug A clear and concise description of what the bug is.

To Reproduce Steps to reproduce the behavior:

1. Go to main page
2. Click on any post
3. Scroll down to heading anchor
4. Click link
5. See overlap

Expected behavior When click the link, User can see their heading

cf. https://stackoverflow.com/questions/4086107/fixed-page-header-overlaps-in-page-anchors

Screenshots If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context Add any other context about the problem here.