<body>
    <div id="wrap">
        <div id="header"></div>
        <div id="nav"></div>
        <div id="main">
            <div id="aside"></div>
            <div id="section"></div>
            <div id="article"></div>
        </div>
            <div id="footer"></div> 
    </div>
</body>
* {
            margin: 0;
            padding: 0;
        }
        body {
            background-color: #E8F5E9 ;
        }
        /* 블록구조를 가운데정렬 할때 width값과 같이 margin 0 auto 주면됨. */
        #wrap {
            width: 1200px;
            margin: 0 auto;             
        }
        #header {
            width: 100%;
            height: 100px;
            background-color: #C8E6C9;
        }
        #nav {
            width: 100%;
            height: 100px;
            background-color: #A5D6A7;
        }
        #main {
            width: 100%;
            overflow: hidden;
        }
        #aside {

            width: 30%;
            height: 780px;
            background-color: #81C784;
            float: left;
        }
        #section{
            width: 40%;
            height: 780px;
            background-color: #66BB6A;
            float: left;
        }
        #article {
            width: 30%;
            height: 780px;
            background-color: #4CAF50;
            float: left;
        }
        #footer {
            width: 100%;
            height: 100px;
            background-color: #43A047;
            
        }
        /* 미디어 쿼리 */
        /* 오류유형01 미디어 쿼리 할때 자식들도 퍼센트로 바꿔주기 */
        @media(max-width : 1300px){
            #wrap{
            width: 96%;
            }
        }
        @media(max-width : 768px){
            #wrap{
            width: 100%
            }
            #aside {
            width: 30%;
            height: 780px;
            }
            #section {
            width: 70%;
            height: 780px;
            }
            #article {
            width: 100%;
            height: 150px;
            }
        }
        @media(max-width : 480px){
            #wrap{
            width: 100%
            }
            #aside{
            width: 100%;
            height: 200px;
            }
            #section {
            width: 100%;
            height: 430px;
            }
        }

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