.mensagem {
    position: fixed;
    top: 0;
    right: 20px;
    background-color: #28a745;
    color: white;
    padding: 15px 20px;
    border-radius: 5px;
    font-size: 16px;
    box-shadow: 0px 4px 8px rgba(0, 0, 0, 0.1);
    opacity: 0;
    transform: translateY(-100%);
    transition: opacity 0.5s ease, transform 0.5s ease;
    z-index: 9999;
}

.mensagem.visivel {
    opacity: 1;
    transform: translateY(60px);
}