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

body {
    font-family: Arial, sans-serif;
    background: linear-gradient(135deg, #0f172a, #1e1b4b, #111827);
    color: white;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.game-container {
    text-align: center;
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid rgba(255,255,255,0.1);
    padding: 30px;
    border-radius: 24px;
    box-shadow: 0 20px 50px rgba(0,0,0,0.35);
    width: 100%;
    max-width: 420px;
}

h1 {
    font-size: 38px;
    margin-bottom: 10px;
    color: #00e5ff;
}

.subtitle {
    color: #cbd5e1;
    margin-bottom: 20px;
    font-size: 16px;
}

.status {
    font-size: 20px;
    font-weight: bold;
    margin-bottom: 25px;
    color: #facc15;
}

.board {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    margin-bottom: 25px;
}

.cell {
    width: 100%;
    aspect-ratio: 1 / 1;
    background: rgba(255,255,255,0.08);
    border: 2px solid rgba(255,255,255,0.1);
    border-radius: 18px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 56px;
    font-weight: bold;
    cursor: pointer;
    transition: 0.25s ease;
    user-select: none;
}

    .cell:hover {
        background: rgba(255,255,255,0.14);
        transform: scale(1.03);
    }

    .cell.x {
        color: #00e5ff;
    }

    .cell.o {
        color: #a855f7;
    }

#restartBtn {
    background: linear-gradient(90deg, #00e5ff, #8b5cf6);
    color: white;
    border: none;
    padding: 14px 24px;
    font-size: 16px;
    border-radius: 14px;
    cursor: pointer;
    font-weight: bold;
    transition: 0.3s ease;
    width: 100%;
}

    #restartBtn:hover {
        transform: translateY(-2px);
    }

@media (max-width: 480px) {
    .game-container {
        padding: 22px;
    }

    h1 {
        font-size: 30px;
    }

    .cell {
        font-size: 48px;
    }
}