Hi there,
Looks okay now, good one 🙂 , though error is still there and can’t find what causes it. I may do some investigation on my end following your setup.
About the styling, style.css is loaded first than cornerstone’s css. And what you add there will be overriden by cornerstone’s css.
What you could do is add your css at cornerstone’s custom css, or add !important to your style value if you prefer to use style.css (eg. color: #000 !important;)
Thanks!