body {
    font-family: Arial, sans-serif;
    background-color: #191919;
    margin: 0;
    padding: 20px;
} 

.gallery {
    column-count: 2;
}

@media(min-width:600px){
    .gallery { column-count: 2; }
}

@media(min-width:900px){
    .gallery { column-count: 4; }
}

@media(min-width:1200px){
    .gallery { column-count: 6; }
}

.gallery img {
    width: 100%;
    display: block;
    margin-bottom: 15px;
}

.modal {
    display: none;
    position: fixed;
    z-index: 999;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.85);
}

.modal-content {
    display: block;
    max-width: 90%;
    max-height: 90%;
    margin: auto;
    margin-top: 3%;
}

.close {
    position: absolute;
    top: 20px;
    right: 30px;
    font-size: 40px;
    color: white;
    cursor: pointer;
}