<title>스파르타코딩클럽 | 부트스트랩 연습하기</title>
        <style>
            .mytitle {
                background-color: green;
                width: 100%;
                height : 250px;
                background-image: url("https://movie-phinf.pstatic.net/20210715_95/1626338192428gTnJl_JPEG/movie_image.jpg")
                background-position: center;
            }
        </style>
</head>
url 넣고 background-position: center; 하면 화면이 없어져요