body{
background-image: url('https://cdn2.aisystem.dev/uploads/phonghopkhonggiay.tnxp.gov.vn/1/NEN-01.png');
    background-repeat: repeat-y;
    background-size: 100% auto;
}
.bb-item img{
width:100%!important;
height:auto!important;
}
/*
.bb-item{
top:0;
left:0;
right:0;
bottom:0;
position:fixed!important;
overflow: hidden;
}*/