#bg-body {
    height: 100vh; /* 这设置高度为视口的100% */
    width: 100vw; /* 这设置宽度为视口的100% */
    background-image: url("/Index/Tpl/images/003.jpg");
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    background-attachment: fixed;
}