body {
    background: #1a1a2e;
    font-family: 'Zen Maru Gothic', sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    margin: 0;
    padding: 10px;
    color: #fff;
    touch-action: manipulation;
}

.game-container {
    background: #16213e;
    padding: 15px;
    border-radius: 20px;
    box-shadow: 0 6px 20px rgba(0,0,0,0.5);
    width: 100%;
    max-width: 440px;
    text-align: center;
    box-sizing: border-box;
}

h1 {
    font-size: 1.3rem;
    color: #00f2fe;
    margin: 0 0 5px 0;
}

p {
    font-size: 0.85rem;
    color: #b2bec3;
    margin-top: 0;
    margin-bottom: 10px;
}
/* SEO・AdSense用テキストボックスのデザイン */
        .seo-text-box {
            margin-top: 50px;
            background-color: #0a2036;
            padding: 25px;
            border-radius: 15px;
            box-shadow: 0 4px 10px rgba(0,0,0,0.05);
            max-width: 600px;
            width: 85%;
            color: #555;
            font-size: 0.95rem;
            line-height: 1.6;
            margin-bottom: 30px;
            border: 1px solid #eee;
        }
        .seo-text-box h2 {
            font-size: 1.2rem;
            color: #c5c5c5;
            margin-top: 0;
            margin-bottom: 12px;
            border-bottom: 2px solid #e0e0e0;
            padding-bottom: 8px;
        }
/* センサー許可ボタン（iOSなどのブラウザ制限対策） */
.permission-btn {
    background: #ff9f43;
    color: white;
    border: none;
    padding: 10px 15px;
    border-radius: 10px;
    font-family: inherit;
    font-weight: bold;
    font-size: 0.9rem;
    margin-bottom: 10px;
    cursor: pointer;
    width: 100%;
    box-shadow: 0 4px 10px rgba(255,159,67,0.3);
}

canvas {
    background: linear-gradient(to bottom, #0f2027, #203a43, #2c5364);
    border-radius: 12px;
    width: 100%;
    max-width: 400px;
    height: auto;
    box-shadow: inset 0 0 15px rgba(0,0,0,0.5);
    display: block;
    margin: 0 auto 15px auto;
}

.result-area {
    margin-bottom: 10px;
}

.result-area.hidden {
    display: none;
}

.main-btn {
    width: 100%;
    padding: 12px;
    font-size: 1.1rem;
    font-family: inherit;
    font-weight: bold;
    background: #00b4d8;
    color: white;
    border: none;
    border-radius: 12px;
    cursor: pointer;
    box-shadow: 0 4px 10px rgba(0,180,216,0.4);
}

.main-btn:active {
    transform: scale(0.95);
    background: #0077b6;
}

.back-btn {
    align-self: flex-start;
    margin-bottom: 10px;
    text-decoration: none;
    color: #b2bec3;
    font-weight: bold;
    background: #16213e;
    padding: 6px 14px;
    border-radius: 20px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
    font-size: 0.9rem;
}