body{
    height: 100%;
    background-image: url('construccion.png');
    background-size: 100% auto;
    background-repeat: no-repeat;
    background-attachment:fixed;
}
.p-50{
    padding: 5px;
    padding-top: 40px;
}
@media (min-width: 576px) {
    .p-50{
        padding: 5px;
        padding-top: 40px;
    }
}
@media (min-width: 768px) {
    .p-50{
        padding: 15px;
    }
}
@media (min-width: 992px) {
    .p-50{
        padding: 35px;
    }
}
@media (min-width: 1200px) {
    .p-50{
        padding: 50px;
    }
}