Follow the below code and change bullet color using css,
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
ul {list-style: none;}
ul li::before {content: "\2022";color: blue;font-weight: bold;display: inline-block; width: 1em;margin-left: -1.5em;}
</style>
</head>
<body>
<h2>Change Bullet Color of List Items</h2>
<ul>
<li>HTML</li>
<li>CSS</li>
<li>Bootstrap</li>
</ul>
</body>
</html>