As the user adeneo said in 2013, the Git Repo contains a demo CSS file if you wish to use it – Demo CSS
Additionally, in the Git Repo under Getting Started, Step 2 shows jquery.steps.css
included in the HTML.
Here is the HTML referenced in the repo:
<!DOCTYPE html>
<html>
<head>
<title>Demo</title>
<meta charset="utf-8">
<script src="https://stackoverflow.com/questions/20030689/jquery.js"></script>
<script src="jquery.steps.js"></script>
<link href="jquery.steps.css" rel="stylesheet">
</head>
<body>
<script>
$("#wizard").steps();
</script>
<div id="wizard"></div>
</body>
</html>
The original poster said this was the correct answer, but it was never posted as an “Answer” so it could not be accepted.