.call_us {
    position: fixed;
    width: 100%;
    height: 60px;
    bottom: 0;
    left: 0;
    background: #F7E700;
    box-shadow: 0 0 10px rgb(0 0 0 / 20%);
    z-index: 100;
    text-align: center;
    text-decoration: none;
    color: #1e1e1e;
    font-size: 18px;
    font-weight: bold;
    text-transform: uppercase;
    line-height: 60px;
    display: none;
}
@media screen and (max-width: 768px)  {
   .call_us  {
       display: block;
   } 
}