.nivel {
    width: 400px;
    margin: 0 auto;
    padding: 20px;
    text-align: center;
    color: yellow;
    border-radius: 20px;
    font-weight: 500;
    font-family: Big John;
    font-size: 40px;
    display: none;
    position: fixed;
    top: 50%;
    left: 0;
    right: 0;
}