It’s really hard to help with this when you post non-css pre-processed stuff. Could you process that CSS and post your demo in a template like below? Or post your demo on CodePen and post the link here (which will display the pen live).
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<style>
/* place CSS here */
</style>
</head>
<body>
<!-- place HTML here -->
</body>
</html>