#game-board {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 15px;
    max-width: 500px;
    margin: 30px auto;
    perspective: 1000px; /* 3D効果のため */
}
.card {
    width: 100%;
    aspect-ratio: 1 / 1; /* 正方形を維持 */
    position: relative;
    cursor: pointer;
    transform-style: preserve-3d;
    transition: transform 0.6s;
}
.card.flipped {
    transform: rotateY(180deg);
}
.card-face {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden; /* 裏面を隠す */
    border-radius: 10px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 3rem;
}
.card-front {
    background-color: var(--main-color);
    color: white;
}
.card-back {
    background-color: #fff;
    transform: rotateY(180deg);
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}
.card.matched .card-back {
    background-color: #d4edda; /* マッチしたら色を変える */
}
/* (既存のスタイルに追記) */
#game-info {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 20px;
    font-size: 1.2rem;
    font-weight: bold;
}
#chisamaru-reaction {
    width: 60px;
}
#chisamaru-reaction svg {
    width: 100%;
    height: auto;
}
/* 応援ちさまるは常に表情モード */
#chisamaru-reaction .bousai-zukin.deep { display: none; }
#chisamaru-reaction .bousai-zukin.shallow { display: block; }

/* --- 応援ちさまる 表情制御 --- */
/* 通常顔 (デフォルト) */
#chisamaru-reaction .eye { /* ... */ }
#chisamaru-reaction .mouth { /* ... */ }

/* 笑顔 (Smile) */
#chisamaru-reaction.smile .eye { d: path("M 65 75 C 75 70, 75 90, 65 85") !important; }
#chisamaru-reaction.smile .eye.right { d: path("M 135 75 C 125 70, 125 90, 135 85") !important; }
#chisamaru-reaction.smile .mouth { d: path("M 80 120 C 100 150, 120 120, 80 120 Z") !important; fill: #333; }

/* しょんぼり (Sad) */
#chisamaru-reaction.sad .eye { d: path("M 65 85 C 75 90, 75 70, 65 75") !important; }
#chisamaru-reaction.sad .eye.right { d: path("M 135 85 C 125 90, 125 70, 135 75") !important; }
#chisamaru-reaction.sad .mouth { d: path("M 90 140 Q 100 130, 110 140") !important; }

/* キラキラ (Sparkle) */
#chisamaru-reaction.sparkle .eye { d: path("M 75 70 L 75 90 M 65 80 L 85 80 M 68 73 L 82 87 M 82 73 L 68 87") !important; fill: none; }
#chisamaru-reaction.sparkle .eye.right { d: path("M 125 70 L 125 90 M 115 80 L 135 80 M 118 73 L 132 87 M 132 73 L 118 87") !important; fill: none; }
#chisamaru-reaction.sparkle .mouth { d: path("M 85 125 C 90 145, 110 145, 115 125") !important; }