.header-banner {
    --bg-color: #77b989;
    background-color: var(--bg-color);
    text-align: center;
    padding: 10px;
    font-size: 16px;
    color: #fff;
    opacity: 1;
    transition: opacity 0.5s ease-in-out;
}

.header-banner.hidden {
    opacity: 0;
}