@media only screen and (max-width:600px){
    .top-header .navbar-nav{
        text-align: center;
    }
    .banner .image img{
        width: 100%;
        margin-top: 10px;
    }
    .about .image img{
        width: 100%;
    }
    .service .gallery img{
        width: 100%;
    }
}