feat: use dark mode icon

src/components/dashboard/NavBar.tsx

@@ -5,7 +5,7 @@ import styled from "styled-components";
 import { stopRecording } from "../../api/recording";
 import { useGlobalInfoStore } from "../../context/globalInfo";
 import { IconButton, Menu, MenuItem, Typography, Chip, Button, Modal, Tabs, Tab, Box, Snackbar, Tooltip } from "@mui/material";
-import { AccountCircle, Logout, Clear, YouTube, X, Update, Close, Language, Brightness7, Brightness4, Description, LightMode } from "@mui/icons-material";
+import { AccountCircle, Logout, Clear, YouTube, X, Update, Close, Language, Brightness7, Brightness4, Description, LightMode, DarkMode } from "@mui/icons-material";
 import { useNavigate } from 'react-router-dom';
 import { AuthContext } from '../../context/auth';
 import { SaveRecording } from '../recorder/SaveRecording';
@@ -114,7 +114,7 @@ export const NavBar: React.FC<NavBarProps> = ({
           }
         }}
       >
-        {darkMode ? <LightMode /> : <Brightness4 />}
+        {darkMode ? <LightMode /> : <DarkMode />}
       </IconButton>
     </Tooltip>
   );