Potential Causes:
In short, this is because the browser can only get the html code we sent in
server.js app.get("in_room"). Nothing else. Because particle.js background requires the particle.js file, the background won't work if the browser cannot access the particle.js file.
This is because we are "sending" the html code within the server.js code and not serving it like a static website, all the other things - everything besides the html code itself, including the theme.css, particles.js, and app.js inside the /html/ folder, are not being sent to the browser when sending the html code in
server.js app.get("in_room").
Current Solution: ignore it. Make the background color the same black as other pages to make it less weird.
who knows why... Fixed. (Dec 12, 2022) in server.js line 316, the queryPromiseGet function is mistakenly overriden, so after running addPeople function once, queryPromiseGet will not be a function anymore