You forgot to link the stylesheets. Include this in the line of your code
<link href="style.css" rel="stylesheet" type="text/css" />. I would also suggest not deleting the template unless necessary.
Firstly, you forgot to link the stylesheet. Link it using the link tag.
<link rel="stylesheet" href="style.css">
And I would recommend using the basic HTML boilerplate rather than only one div. Here is the link to my repl with the code: