How to make a professional looking UI?

[dezmo]

You can start with e.g.:

https://ruby.sketchup.com/UI/HtmlDialog.html

https://github.com/SketchUp/htmldialog-examples

https://forums.sketchup.com/search?q=html%20category%3A13

https://forums.sketchup.com/t/ruby-learning-resources-wikilists/22861