.edit_course{
        margin-bottom: 3px;
        margin-top: 10px;
        padding: 5px 0px;
        width: 90px;
        font-size: 14px;
    }
    .invite{
        
        font-size: 16px;
        width: 60px;
        padding: 0px;
        margin-left: 10px;
        margin-bottom: 3px;
        margin-top: 10px;
    }
    .skip{
        font-size: 16px;
        width: 60px;
        padding: 4px;
        margin-left: 18px;
        margin-top: 10px;
    }
    .preview{
        text-align: center;
        padding: 5px 0px; 
        width: 60px;
        margin-left: -40px;   
    }
    @media all and (max-width: 400px) {
        .tbl_responsive {
           max-width: 200px;            
        }
    }
    
    @media all and (min-width: 1000px) {
        .edit_course{
        padding: 5px 0px;
        width: 90px;
        font-size: 14px;
    }
    .invite{
        font-size: 16px;
        width: 60px;
        padding: 0px;
        margin-left: -70px;
    }
    .skip{
        font-size: 16px;
        width: 60px;
        padding: 4px;
        margin-left: -100px;
    }
}

