BODY{
    background-image: url('images/pic10.jpg');
    background-repeat: no-repeat;
    background-size:cover;
}
<style>
    body { font-family: Arial, sans-serif; text-align: center; margin: 25px; }
    button { padding: 10px 20px; font-size: 16px; }
    #result { margin-top: 20px; font-size: 18px; color: #d45d00; }

   

@keyframes glow {
    0% { 
        box-shadow: 0 0 20px #fff700, 0 0 30px #fff700, 0 0 40px #fff700; /* 明るい黄色 */
    }
    50% { 
        box-shadow: 0 0 40px #fff700, 0 0 70px #fff700, 0 0 100px #fff700; 
    }
    100% { 
        box-shadow: 0 0 20px #fff700, 0 0 30px #fff700, 0 0 40px #fff700; 
    }
}

.glowing {
    animation: glow 1s infinite;
}

.overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(255, 255, 255, 0.9); /* 明るいオーバーレイ */
    opacity: 0;
    transition: opacity 1s;
    pointer-events: none; /* クリックを無効化 */
}

.overlay.active {
    opacity: 1; /* 光る効果を表示 */
    pointer-events: auto; /* クリックを有効化 */
}

    .glowing {
        animation: glow 1s infinite;


    }
niji
</style>