• style is missing

• document.body.offsetHeight is 0 fallback on window.innerHeight which breaks the parent element value provided by the function create_svg() call

• CSSStyleSheet() throws an error, fallback on appending style element but menu still using style construction

issue report from Graphviz forum
originally tried opening this in Safari, which shows a blank page. Opening the Web Inspector, I saw the following error:

[Error] Unhandled Promise Rejection: TypeError: function is not a constructor (evaluating 'new CSSStyleSheet()')
(anonymous function) (render.js:155)
promiseReactionJob
Right now, that feature is available in about half of installed browsers: https://caniuse.com/#feat=mdn-api_cssstylesheet (including, apparently, the latest Safari, despite my personal experience)

You might want to consider adding a polyfill for stylesheet construction, or adding a message about browser support.

Let's try a 3D shadow/lighting effect with Lume. I'll give it a shot if you haven't already by the time I swing back here.