Bulma
Bulma is a free, open source CSS framework based on Flexbox and used by more than 200,000 developers.
Starter template
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Hello Bulma!</title>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bulma@0.9.0/css/bulma.min.css">
</head>
<body>
<section class="section">
<div class="container">
<h1 class="title">
Hello World
</h1>
<p class="subtitle">
My first website with <strong>Bulma</strong>!
</p>
</div>
</section>
</body>
</html>
official bulma.io