:root {
    --purple: #8A2BE2;
    --green: #00ff41;
    --blue: #00e0ff;
    --dark: #0a0a0f;
    --card-bg: rgba(255, 255, 255, 0.08);
}

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

body {
    background: radial-gradient(circle at 10% 30%, rgba(138, 43, 226, 0.15) 0%, transparent 50%),
                radial-gradient(circle at 90% 70%, rgba(0, 224, 255, 0.15) 0%, transparent 50%),
                var(--dark);
    color: white;
    font-family: 'Segoe UI', monospace, sans-serif;
    min-height: 100vh;
    padding: 20px;
    text-align: center;
}

.header {
    text-align: center;
    margin-bottom: 20px;
    background: linear-gradient(90deg, var(--purple), var(--blue));
    padding: 15px;
    border-radius: 12px;
    box-shadow: 0 10px 30px rgba(138, 43, 226, 0.4);
}

.stats {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
    margin-bottom: 20px;
    max-width: 400px;
    margin-left: auto;
    margin-right: auto;
}

.stat-box {
    background: var(--card-bg);
    padding: 15px;
    border-radius: 10px;
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(5px);
}

.grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
    margin: 20px auto;
    max-width: 400px;
}

.card {
    position: relative;
    width: 100%;
    aspect-ratio: 1;
    cursor: pointer;
    perspective: 800px;
    user-select: none;
}

.card-inner {
    position: absolute;
    width: 100%;
    height: 100%;
    transition: transform 0.5s cubic-bezier(0.4, 0.2, 0.2, 1);
    transform-style: preserve-3d;
}

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

.card-face {
    position: absolute;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 8px;
    backface-visibility: hidden;
    font-size: 24px;
    font-weight: bold;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.3);
}

.card-front {
    background: var(--purple);
}

.card-back {
    background: var(--green);
    transform: rotateY(180deg);
}

.card.matched .card-back {
    background: #00ff41;
    box-shadow: 0 0 15px rgba(0, 255, 65, 0.5);
}

.controls {
    display: flex;
    gap: 10px;
    justify-content: center;
    margin-top: 20px;
    flex-wrap: wrap;
}

button {
    background: var(--blue);
    color: black;
    border: none;
    padding: 10px 20px;
    border-radius: 5px;
    cursor: pointer;
    font-weight: bold;
    transition: all 0.3s ease;
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0, 224, 255, 0.4);
}

@media (max-width: 480px) {
    .grid {
        grid-template-columns: repeat(3, 1fr);
    }
    .stats {
        grid-template-columns: repeat(2, 1fr);
    }
}