feat: update Mermaid diagrams to follow theme preference (#576)

Tim van Wijk

20.22.2025 902d1bfcae166cf9b0350bb88810e3c0162430a3

 exampleSite/config/_default/hugo.toml

@@ -22,6 +22,10 @@
# Localized dates requires Hugo version 0.87.0
localizedDates = false

# Mermaid
[params.mermaid]
enable = true

[markup]
    [markup.goldmark]
      [markup.goldmark.renderer]