:root {
    --bg-color: #0f172a;
    --glass-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
    --primary-color: #38bdf8;
    --secondary-color: #818cf8;
    --text-color: #f1f5f9;
    --card-back: linear-gradient(135deg, #1e293b 0%, #0f172a 100%);
    --card-front: rgba(255, 255, 255, 0.08);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Outfit', 'Noto Sans JP', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow-x: hidden;
}

/* 背景アニメーション */
.background-animation {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    background: radial-gradient(circle at 20% 30%, #1e293b 0%, transparent 40%),
        radial-gradient(circle at 80% 70%, #1e1b4b 0%, transparent 40%);
}

.game-container {
    width: 95%;
    max-width: 800px;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    gap: 2rem;
    z-index: 1;
}

.game-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.title {
    font-size: 2.5rem;
    font-weight: 600;
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: -1px;
}

.stats-container {
    display: flex;
    gap: 1.5rem;
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(10px);
    padding: 0.5rem 1.5rem;
    border-radius: 12px;
}

.stat-item .label {
    font-size: 0.75rem;
    text-transform: uppercase;
    opacity: 0.7;
    margin-bottom: 2px;
}

.stat-item .value {
    font-size: 1.25rem;
    font-weight: 600;
    font-family: monospace;
    transition: color 0.3s ease;
}

.stat-item.warning .value {
    color: #f87171;
    text-shadow: 0 0 10px rgba(248, 113, 113, 0.5);
}

.stat-item.penalty-flash {
    animation: penalty-shake 0.5s cubic-bezier(.36, .07, .19, .97) both;
}

@keyframes penalty-shake {

    10%,
    90% {
        transform: translate3d(-1px, 0, 0);
    }

    20%,
    80% {
        transform: translate3d(2px, 0, 0);
    }

    30%,
    50%,
    70% {
        transform: translate3d(-4px, 0, 0);
        background-color: rgba(248, 113, 113, 0.2);
    }

    40%,
    60% {
        transform: translate3d(4px, 0, 0);
    }
}

/* ゲームボード */
.game-board {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(80px, 1fr));
    gap: 15px;
    width: 100%;
    perspective: 1000px;
}

/* カードのデザイン */
.card {
    aspect-ratio: 2/3;
    position: relative;
    cursor: pointer;
    transform-style: preserve-3d;
    transition: transform 0.6s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.card:hover {
    transform: scale(1.05);
}

.card.flipped {
    transform: rotateY(180deg);
}

.card.matched {
    cursor: default;
    pointer-events: none;
}

.card-face {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: 12px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 2rem;
    font-weight: bold;
    border: 1px solid var(--glass-border);
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
}

.card-front {
    background: var(--card-front);
    backdrop-filter: blur(5px);
    transform: rotateY(180deg);
    color: var(--primary-color);
}

.card-back {
    background: var(--card-back);
    background-size: cover;
    display: flex;
    justify-content: center;
    align-items: center;
}

.card-back::after {
    content: '?';
    font-size: 2.5rem;
    opacity: 0.2;
    color: var(--text-color);
}

/* ボタン */
.glass-btn {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(10px);
    color: var(--text-color);
    padding: 0.8rem 2rem;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    width: fit-content;
    margin: 0 auto;
    display: block;
}

.glass-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.glass-btn.primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border: none;
    color: #000;
}

.game-footer {
    width: 100%;
    display: flex;
    justify-content: center;
}

/* モーダル */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(15, 23, 42, 0.7);
    backdrop-filter: blur(8px);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

.modal.hidden {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
}

.modal-content {
    padding: 3rem;
    border-radius: 2rem;
    text-align: center;
    max-width: 400px;
    width: 90%;
    transform: translateY(0);
    transition: transform 0.3s ease;
}

.modal.hidden .modal-content {
    transform: translateY(20px);
}

.modal h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.modal-stats {
    margin: 2rem 0;
    display: flex;
    justify-content: center;
    gap: 2rem;
}

.modal-stats p {
    font-size: 1.1rem;
    opacity: 0.8;
}

.modal-stats span {
    display: block;
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--text-color);
}

@media (max-width: 600px) {
    .game-board {
        grid-template-columns: repeat(4, 1fr);
        gap: 10px;
    }

    .title {
        font-size: 1.8rem;
    }

    .stats-container {
        gap: 0.5rem;
    }

    .stat-item {
        padding: 0.4rem 0.8rem;
    }
}

/* 一致した時の特別なアニメーション */
.card.matched-animation {
    animation: match-pulse 0.6s cubic-bezier(0.45, 0.05, 0.55, 0.95);
}

@keyframes match-pulse {
    0% {
        transform: rotateY(180deg) scale(1);
    }

    50% {
        transform: rotateY(180deg) scale(1.1);
        filter: brightness(1.5) drop-shadow(0 0 15px var(--primary-color));
    }

    100% {
        transform: rotateY(180deg) scale(1);
    }
}

.card.matched-fade-out {
    animation: match-fade-out 0.8s ease-in forwards;
}

@keyframes match-fade-out {
    0% {
        transform: rotateY(180deg) scale(1);
        opacity: 1;
    }

    100% {
        transform: rotateY(180deg) scale(0.5);
        opacity: 0;
        visibility: hidden;
    }
}

/* パーティクルエフェクト */
.particle {
    position: fixed;
    pointer-events: none;
    z-index: 1000;
    border-radius: 50%;
}

@keyframes particle-fade-out {
    0% {
        transform: translate(0, 0) scale(1);
        opacity: 1;
    }

    100% {
        transform: translate(var(--tx), var(--ty)) scale(0);
        opacity: 0;
    }
}

/* 浮遊テキスト */
.floating-text {
    position: fixed;
    pointer-events: none;
    z-index: 1001;
    font-weight: 700;
    font-size: 1.5rem;
    color: var(--primary-color);
    text-shadow: 0 0 10px rgba(56, 189, 248, 0.5);
    animation: float-up-fade 1s ease-out forwards;
}

@keyframes float-up-fade {
    0% {
        transform: translateY(0);
        opacity: 0;
    }

    20% {
        opacity: 1;
    }

    100% {
        transform: translateY(-50px);
        opacity: 0;
    }
}