body, html {
    margin: 0;
    padding: 0;
    width: 100%;
  }
  
.gallery {
    column-count: 1;
    column-gap: 0;
    width: 100%;
    max-width: 600px;
    margin: auto;
}

.gallery img {
    width: 100%;
    margin-bottom: 8px;
    display: block;
}