.attachment-preview .loading-bar{height:4px;background:linear-gradient(90deg,rgba(0,0,0,.2) 25%,rgba(0,0,0,.1) 50%,rgba(0,0,0,.2) 75%);background-size:200% 100%;animation:loading 1.5s infinite}@keyframes loading{0%{background-position:200% 0}to{background-position:-200% 0}}