*{margin:0;padding:0}body{background-color:#000;overflow:hidden;display:flex;align-items:center;justify-content:center;height:100vh}#app{width:min(100vw,100vh * 16/9);height:min(100vh,100vw * 9/16)}canvas{width:100%;height:100%;outline:none}#fullscreen-btn{position:fixed;bottom:20px;right:20px;width:40px;height:40px;border:1px solid rgba(255,255,255,.3);background-color:#000000b3;color:#fff;font-size:20px;border-radius:8px;cursor:pointer;z-index:1000;transition:all .3s ease;display:flex;align-items:center;justify-content:center}#fullscreen-btn:hover{background-color:#fff3;transform:scale(1.1)}#fullscreen-btn:active{transform:scale(.95)}