.demo{position:relative;width:100%;max-width:var(--linemax);height:var(--height, 300px);border-radius:.5rem;overflow:hidden;margin:0 0 1em;box-shadow:inset 1px 1px 5px #0000001a;background:#f4f4f4}.demo:before{content:"loading...";display:flex;width:100%;height:100%;align-items:center;justify-content:center;font-size:16px;opacity:.5}.demo canvas{animation:fade-in .4s}@keyframes fade-in{0%{opacity:0}to{opacity:1}}