1:thisを使いこなす
mixinとSCSSは1と同じなので省略
HTMLの記述
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<link rel="stylesheet" href="style.css">
<link href="https://fonts.googleapis.com/css2?family=Teko:wght@500&display=swap" rel="stylesheet">
</head>
<body>
<div id="container">
<div class="animate-title">
PLAY ANIMATION
</div>
<div class="animate-title-2">
ANIMATIONNNNNNNNN
</div>
<button id="btn">Animation</button>
</div>
<script src="main.js"></script>
</body>
</html>