body.mobile {
  /*
    background: url("../assets/img/bgm.jpg") no-repeat center center;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
    */
}

body.main.mobile {
  /*background-image: url(../img/bgm.jpg)*/
}