#edPreviewWrap{position:relative;} #edPreviewWrap::before{content:"";position:absolute;top:0;left:0;height:3px;width:100%;background:linear-gradient(90deg,transparent,var(--brand-cyan,#2BD0C5),transparent);background-size:200% 100%;animation:edScan 2.6s linear infinite;z-index:2;} @keyframes edScan{0%{background-position:200% 0;}100%{background-position:-200% 0;}}