html,body,#app{height:100%;margin:0;font-family:Arial,sans-serif}.app-shell{flex-direction:column;height:100vh;display:flex}.app-header{color:#fff;box-sizing:border-box;background:#1f2937;flex-shrink:0;align-items:center;height:60px;padding:0 20px;display:flex}.app-body{flex:1;min-height:0;display:flex}.app-sidebar{box-sizing:border-box;background:#f3f4f6;border-right:1px solid #d1d5db;width:280px;min-height:0;padding:16px;overflow:hidden auto}.app-sidebar h3{margin-top:0}.app-sidebar p{margin:0 0 12px}.app-sidebar button{cursor:pointer;background:#e5e7eb;border:1px solid #ccc;padding:10px 14px}.app-viewer{background:#cbd5e1;flex:1;min-width:0;min-height:0;position:relative}