body {
    background: #1a1a2e;
    font-family: 'Zen Maru Gothic', sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    margin: 0;
    padding: 10px;
    color: #fff;
    overscroll-behavior: none; /* スワイプ時のリロード防止 */
}

.game-container {
    width: 100%;
    max-width: 400px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
}

.header {
    text-align: center;
}

.header h1 {
    margin: 0;
    font-size: 1.4rem;
    color: #00f2fe;
}

.header p {
    margin: 5px 0 0 0;
    font-size: 1.2rem;
    font-weight: bold;
}
/* SEO・AdSense用テキストボックスのデザイン */
        .seo-text-box {
            margin-top: 40px;
            background-color: #fff;
            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: #333;
            margin-top: 0;
            margin-bottom: 12px;
            border-bottom: 2px solid #f0f0f0;
            padding-bottom: 8px;
        }
.combo-text {
    color: #ff4757;
    margin-left: 10px;
}

.canvas-wrapper {
    position: relative;
    background: #0f172a;
    border-radius: 12px;
    box-shadow: 0 0 15px rgba(0, 242, 254, 0.2);
    overflow: hidden;
}

canvas {
    display: block;
    width: 100%;
    max-width: 320px;
    height: auto;
}

/* スタート画面・結果画面のオーバーレイ */
.overlay {
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 10;
}
.overlay.hidden {
    display: none;
}

/* 操作ボタン（2種類） */
.controls {
    display: flex;
    width: 100%;
    max-width: 320px;
    gap: 10px;
}

.action-btn {
    flex: 1;
    padding: 20px 0;
    font-size: 1.1rem;
    font-weight: bold;
    font-family: inherit;
    border: none;
    border-radius: 12px;
    color: white;
    cursor: pointer;
    touch-action: manipulation; /* 連続タップ時のズームを防止 */
    box-shadow: 0 4px 0 rgba(0,0,0,0.3);
}

.action-btn:active {
    transform: translateY(4px);
    box-shadow: none;
}

.left-btn { background: #ff4757; }
.right-btn { background: #1e90ff; }

.main-btn {
    padding: 12px 24px;
    font-size: 1.1rem;
    font-weight: bold;
    background: #00b4d8;
    color: white;
    border: none;
    border-radius: 12px;
    cursor: pointer;
}

.back-btn {
    align-self: flex-start;
    margin-bottom: 10px;
    text-decoration: none;
    color: #a0a0b8;
    background: #2a2a40;
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 0.9rem;
}