clean up unused js css

frontend/pages/_app.tsx

@@ -25,16 +25,6 @@ const useStyles = makeStyles((theme) => ({
         height: '100vh',
         overflow: 'auto',
     },
-    toolbar: {
-        paddingRight: 24, // keep right padding when drawer closed
-    },
-    toolbarIcon: {
-        display: 'flex',
-        alignItems: 'center',
-        justifyContent: 'flex-end',
-        padding: '0 8px',
-        ...theme.mixins.toolbar,
-    },
     title: {
         flexGrow: 1,
     },