Set half-opacity for empty state

Signed-off-by: Alex Andreev <alex.andreev.email@gmail.com>

src/renderer/components/+nodes/route.tsx

@@ -93,7 +93,9 @@ export class NodesRoute extends React.Component {
 
     if (!metrics || metrics.length < 2) {
       return (
+        <div className="opacity-50">
           <VerticalBar value={0}/>
+        </div>
       );
     }