@keyframes fadeIn {
    from { opacity: 0; }    
    to { opacity: 1; }
}

.popup {
    position: fixed;
    top: 0;
    left: 0;
    display: none;
    align-items: center;
    justify-content: center;
    width: 100%;
    height: 100vh;
    background-color: rgba(0, 0, 0, .75);
    z-index: 999;
}

.popup-banner {
    position: relative;
}
    
.popup-close {
    position: absolute;
    top: -15px;
    right: -15px;
    display: block;
    width: 30px;
    height: 30px;
    line-height: 30px;
    font-size: 1.5rem;
    border-radius: 50%;
    text-align: center;
    color: white;
    background-color: black;
    cursor: pointer;        
}

.open {
    display: flex;
    animation: fadeIn .7s;
}