.contact_us {
    margin-top: 5%;
    padding-bottom: 5%;
}

#first_name {
    max-width: 44%; /*max-width for responsiveness*/
    float: left;
}

#second_name {
    margin-left: 2%;
    max-width: 44%;
    float: left;
}

#submit_form {
    margin-top: 1%;
}