html {
    width: 100%;
    margin: 0 auto;
    position: relative;
    background: url(../images/bg1.jpg) no-repeat center top;
    background-size: cover;
    overflow: hidden;
    overflow-y: auto;
    height: 100%;
}
body {
    overflow: hidden;
    position: relative;
    max-width: 1920px;
    margin: auto;
    min-height: 870px;
    height: 100%;
    background: url(../images/bg1.jpg) no-repeat center top;
    background-size: cover;
}