docs: fix copy to clipboard button visibility in light mode (#826)

This PR fixes the issue #791 and updated the info box color so that tags
are visible in dark mode as well in docsite.

.hugo/assets/scss/_styles_project.scss

@@ -0,0 +1 @@
+@import 'td/code-dark';

.hugo/hugo.toml

@@ -48,7 +48,11 @@ enableRobotsTXT = true
   pre = "<i class='fa-brands fa-github'></i>"
 
 [markup.goldmark.renderer]
-  unsafe= true 
+  unsafe= true
+
+[markup.highlight]
+  noClasses = false
+  style = "tango"
 
 [outputFormats]
   [outputFormats.LLMS]