Rendering from Pod to HTML is done using MetaCPAN::Pod::XHTML. This is based on Pod::Simple::XHTML, with some adjustments. There is then some post-processing to restrict what HTML can be used, and to link images correctly.

Syntax highlighting is done using JavaScript, and there are CSS rules to style everything.

A while back, I wrote TOBYINK::Pod::HTML which generates fairly clean HTML or XHTML, and syntax highlights code using PPI::HTML, Syntax::Highlight::RDF, or Syntax::Highlight::Engine::Kate depending on the language being syntax highlighted (because it doesn't just support Perl!).

It comes with a command-line tool allowing you to do:

pod2html-tobyink --code_highlighting --pretty --output=xhtml path/to/d
+oc.pod >path/to/doc.html
[download]

But you probably want to write your own command-line tool if you want to pass in different options for code highlighting colours, etc.

Also consider Web::PerlDistSite which wraps TOBYINK::Pod::HTML and provides a static-site generator for quickly creating flashy websites for a Perl distribution. The documentation is a little sparse, but once you've set it up once, it's fairly easy to use.

This is what is used by, for example, the Type::Tiny website.

The next better step would be to dive into MetaCPAN's source code and find the controller for that pod2html URL, which probably shows you a minimalist way to get the job done, which you could then port to your own web app, maybe installing MetaCPAN libraries as a dependency.

So many options...

Overwhelmed by choice is the downside of TIMTOWTDI!

IIRC the latter is achieved with JS.

You'd need to install and run metacpan locally.

https://metacpan.org/about/development

Edit

Otherwise, maybe better having a try with Pod::POM::Web and patching the look.