:root {
    --primary: #7900ff;
    --secondary: #2575fc;
    --accent: #fd5e53;
    --light: #ffffff;
    --dark: #2c3e50;
    --success: #4CAF50;
    --warning: #FFC107;
    --error: #F44336;
    --card-bg: #f8f9fa;
    --card-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Arial', sans-serif;
}

body {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: var(--light);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 20px;
}

.game-container {
    max-width: 800px;
    width: 100%;
    margin: 0 auto;
    text-align: center;
}

h1 {
    margin: 20px 0;
    font-size: 2.5rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.game-info {
    display: flex;
    justify-content: space-between;
    margin-bottom: 20px;
    background: rgba(255, 255, 255, 0.1);
    padding: 15px;
    border-radius: 10px;
    backdrop-filter: blur(5px);
}

.info-item {
    font-size: 1.2rem;
    font-weight: bold;
}

.game-board {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 15px;
    margin: 20px auto;
    max-width: 600px;
}

.card {
    aspect-ratio: 1;
    border-radius: 10px;
    cursor: pointer;
    font-size: 2rem;
    font-weight: bold;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
    transform-style: preserve-3d;
    position: relative;
    transform: rotateY(0deg);
}

.card-front, .card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    backface-visibility: hidden;
    transition: var(--transition);
}

.card-front {
    background: var(--card-bg);
    color: var(--dark);
    transform: rotateY(180deg);
}

.card-back {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    transform: rotateY(0deg);
}

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

.card.matched .card-front {
    background: var(--success);
    color: white;
}

.controls {
    margin-top: 30px;
}

.btn {
    padding: 12px 25px;
    border: none;
    border-radius: 30px;
    font-size: 1rem;
    font-weight: bold;
    cursor: pointer;
    transition: var(--transition);
    background: var(--accent);
    color: white;
    box-shadow: 0 4px 8px rgba(253, 94, 83, 0.3);
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 12px rgba(253, 94, 83, 0.4);
}

.btn:active {
    transform: translateY(1px);
}

.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 100;
    opacity: 0;
    pointer-events: none;
    transition: var(--transition);
}

.modal.show {
    opacity: 1;
    pointer-events: all;
}

.modal-content {
    background: white;
    color: var(--dark);
    padding: 30px;
    border-radius: 15px;
    text-align: center;
    max-width: 400px;
    width: 90%;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    transform: translateY(-50px);
    transition: var(--transition);
}

.modal.show .modal-content {
    transform: translateY(0);
}

.modal h2 {
    margin-bottom: 15px;
    color: var(--primary);
}

.modal p {
    margin-bottom: 20px;
    font-size: 1.1rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    h1 {
        font-size: 2rem;
    }

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

    .card {
        font-size: 1.5rem;
    }

    .game-info {
        flex-direction: column;
        gap: 10px;
    }

    .info-item {
        font-size: 1rem;
    }
}

@media (max-width: 480px) {
    h1 {
        font-size: 1.8rem;
    }

    .game-board {
        gap: 8px;
    }

    .card {
        font-size: 1.2rem;
    }

    .btn {
        padding: 10px 20px;
        font-size: 0.9rem;
    }
}