Why is stylesheet only working for the index page, but not for any extensions of the index page?
Why css does not apply when complete url is entered like home/index
You're using a relative URL for the stylesheet; you need to prepend a forward slash so that it's relative to the root and not the page being viewed.
<link rel="stylesheet" type="text/css" href="/static/style.css" />
Ref:
https://stackoverflow.com/questions/44038534/why-is-stylesheet-only-working-for-the-index-page-but-not-for-any-extensions-of