.fold{width:40px;height:40px;pointer-events:none}.fold,.fold:before{position:absolute;top:0;right:0}.fold:before{content:"";border-style:solid;border-width:0 40px 40px 0;border-color:transparent var(--fold-bg) var(--fold-shadow) transparent;transition:all .3s ease;background:var(--fold-bg)}