.demo {
    opacity: 0.6;
}

.modal {
    display: none;
    position: fixed;
    z-index: 1;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0, 0, 0, 0.8);
}

.modal-content {
    position: relative;
    margin: auto;
    padding: 0;
    width: 80%;
    max-width: 700px;
}

.mySlides {
    display: none;
}

.close {
    position: absolute;
    top: 10px;
    right: 25px;
    color: white;
    font-size: 35px;
    font-weight: bold;
    cursor: pointer;
}

.iframe_size {
    height: 315px;
    width: 500px;
}

@media only screen and (max-width: 768px) {
    .iframe_size {
        height: 200px;
        width: 350px;
    }
}