By looking at those sites and their sources, you may better see what’s possible and how it’s achieved.
ddoc
Of course this site is made with ddoc.
See the source at https://github.com/Canop/ddoc/tree/main/website
bacon
bacon’s website looks a lot like the one of ddoc, except colors don’t try to be neutral.
website: https://dystroy.org/bacon
Source: https://github.com/Canop/bacon/tree/main/website
broot
broot’s website is similar to ddoc’s too, but shows how a bigger documentation fits ddoc without problem.
To support tabs wrapping configuration snippets, a small script is injected.
You can consult it in /website/src/js.
website: https://dystroy.org/broot
Source: https://github.com/Canop/broot/tree/main/website
dysk
website: https://dystroy.org/dysk
Source: https://github.com/Canop/dysk/tree/main/website
rhit
This site sports a different layout, with vertical navigation stripes.
website: https://dystroy.org/rhit