interact.html

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">

<style>
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  height: 100%;
  position: relative;
  margin: 0;
  padding: 0;
}

.aura {
  position: absolute;
  border: 1px solid #000;
  border-radius: 50%;
  background: #00f;
  transform: translate(-50%, -50%);
  opacity: .05;
}
</style>
</head>
<body>

<script src="interact.js"></script>
</body>
</html>