@media only screen and (max-width: 426px) {
    /*in Mobile*/
    .today_in_history span.desktop_only_h {
        display: none;
    }
    .today_in_history span.mobile_only_h {
        display: inline;
    }
}

@media only screen and (min-width: 426px) {
    /* For desktop: */
    .today_in_history span.desktop_only_h {
            display: inline-block;
        }
    .today_in_history span.mobile_only_h {
        display: none;
    }     
}