body {
    font-family: sans-serif;
    background-color: #f0f0f0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.container {
    background-color: #fff;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    text-align: center;
}

.game-area {
    margin-bottom: 20px;
}

.note-row {
    display: flex;
    justify-content: center;
    gap: 15px;
}

.note {
    width: 60px;
    height: 100px;
    background-color: #ccc;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.note:hover {
    background-color: #ddd;
}

.note.selected {
    background-color: #4CAF50;
}

.note.wrong {
    background-color: #f44336;
}

#start-button {
    padding: 10px 20px;
    font-size: 16px;
    background-color: #4CAF50;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}