index.html
<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>My Tailwind CSS</title>
<script src="https://cdn.tailwindcss.com"></script>
</head>
<body>
<div class="bg-red-400 w-40 h-40">Box 1</div>
<div class="bg-sky-400 w-[160px]">Box 2</div>
<div class="bg-orange-400 w-3/4">Box 3</div>
<div class="bg-green-400 w-[75%]">Box 4</div>
</body>
</html>