<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF-8">
<title>カウントダウンゲーム</title>
<style>
#game {
display: flex;
flex-wrap: wrap;
justify-content: center;
gap: 10px;
max-width: 200px;
margin: 0 auto;
}
.box {
width: 50px;
height: 50px;
background-color: lightblue;
display: flex;
align-items: center;
justify-content: center;
font-size: 20px;
}
#infobox {
margin-top: 20px;
font-size: 24px;
text-align: center;
}
</style>
</head>
<body>
<hr>
<h1 align="center">3秒以内に「当たり」を見つけよう！</h1>
<hr>
<div id="game">
<div class="box">1</div>
<div class="box">2</div>
<div class="box">3</div>
<div class="box">4</div>
<div class="box">5</div>
<div class="box">6</div>
<div class="box">7</div>
<div class="box">8</div>
<div class="box">9</div>
<div class="box">10</div>
</div>
<button id="startButton" style="display: block; margin: 20px auto;">スタート</button>
<div id="infobox">3秒前</div>
<hr>
<script src="countdown.js"></script>
</body>
</html>
