@media only screen and (max-width: 320px){
    header {
        position: relative;
        height: auto;
    }
/*    .container_pad {
        margin-top: 31px;
    }*/
}

@media only screen and (min-width: 321px) and (max-width: 480px){
    header {
        position: relative;
        height: auto;
    }
/*    .container_pad {
        margin-top: 31px;
    }*/
}

@media only screen and (min-width: 768px) and (max-width: 1024px){
    header {
        position: fixed;
        height: auto;
    }
/*    .container_pad {
        margin-top: 31px;
    }*/
}

@media only screen and (min-width: 1025px){
    header {
        position: fixed;
        height: auto;
    }
/*    .container_pad {
        margin-top: 31px;
    }*/
}