I had this problem too, where my app wasn’t loading style sheets and the like. However, I was importing my assets directly into my index.html entry point.
By replacing the links with absolute paths as per this documentation, my problem was resolved.
For me, this meant changing
<head>
<link rel="stylesheet" href="https://stackoverflow.com/questions/40426011/./style.css" ></link>
</head>
to this:
<head>
<link rel="stylesheet" href="https://stackoverflow.com/style.css" ></link>
</head>
I’m not sure if the same thing would work for your import statements, but it is worth a shot.
FYI I’m using the project layout from create-react-app.