#site-header{position:fixed;top:0;width:100%;box-shadow:0 -1px 4px #767676;backdrop-filter:blur(.4rem);z-index:1000;transition:top 0.8s ease,opacity 0.7s ease,background-color 0.16s ease-in,color 0.16s ease-in;&.hidden{top:-100px;opacity:0}}.bg-card{position:fixed;top:0;width:90vh}.bg-card--left{top:-10vh;left:0}.bg-card--right{right:0}