Fix chagne className(introduction -> intro)

frontend/src/pages/Main.js

@@ -3,7 +3,7 @@ import { useNavigate } from 'react-router-dom';
 import { UserContext } from '../Context.js';
 import Article from '../components/Article.js';
 import React, { useEffect, useState, useContext } from 'react';
-
+import '../css/Main.css';
 import axios from 'axios';
 axios.defaults.withCredentials = true;
 
@@ -48,7 +48,7 @@ function Main() {
   return (
     <div className="App">
       <h1>모두의 食道樂</h1>
-      <div className="introduction">
+      <div className="intro">
         가보고 싶은 식당을 찾아보고, 가본 식당을 기록해보세요!
       </div>
       <div style={{ display: 'flex' }}>