html, body{
height:100%;
margin:0;
}

.container{
display:flex;
height:100vh;
width: 100vw;
}

.left-panel{
width:240px;
background:#f3f3f3;
overflow-y: auto;
padding:10px;
}

.right-panel{
flex: 1;
background:#111;
position:relative;
}

#viewer{
width:100%;
height:100%;
}