body {
    font-family: Arial, sans-serif;
    background: #f0f4f8;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

.merge-lab-container {
    text-align: center;
    background: #ffffff;
    padding: 20px 30px;
    border-radius: 15px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.2);
}

h1 {
    margin-bottom: 15px;
    color: #333;
}

.game-info {
    display: flex;
    justify-content: space-between;
    max-width: 300px;
    margin: 10px auto;
    font-weight: bold;
    color: #555;
}

.grid {
    display: grid;
    grid-template-columns: repeat(5, 60px);
    grid-template-rows: repeat(5, 60px);
    gap: 10px;
    justify-content: center;
    margin: 20px auto;
}

.cell {
    background: #e0e4e8;
    border-radius: 10px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-weight: bold;
    font-size: 18px;
    cursor: pointer;
    user-select: none;
    transition: all 0.2s ease;
}

.cell[data-level="1"] { background: #ffd6d6; }
.cell[data-level="2"] { background: #ffb3b3; }
.cell[data-level="3"] { background: #ff8080; }
.cell[data-level="4"] { background: #ff4d4d; }
.cell[data-level="5"] { background: #ff1a1a; color: white; }

#restart {
    padding: 8px 20px;
    font-size: 16px;
    border: none;
    border-radius: 8px;
    background: #4caf50;
    color: white;
    cursor: pointer;
    transition: background 0.2s ease;
}

#restart:hover {
    background: #45a049;
}