Created using https://twinery.org/.
Big shout out to https://happycoding.io/tutorials/html/hosting and http://jmcglone.com/guides/github-pages/ for teaching me how to use Github Pages create my own website (!) to host the .html project file Twinery exported. The domain used for this project [anxietyflowchart.com] was bought from https://porkbun.com/ because it was cheap and I loved that this particular domain registrar is a small & indie player in the space. As a really big bonus, they made it REALLY easy to connect the domain to Github Pages from this article in their knowledge base https://kb.porkbun.com/article/64-how-to-connect-your-domain-to-github-pages.
I made it mobile friendly by doing what user greywolf suggested from here. Basically edit the .html file with a text editor and add the following viewport meta element to the head section of the file:
<meta name="viewport" content="width=device-width,initial-scale=1" />
The top of the code should basically look like this:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1" />
<title>The name of the Story project</title>
...