@media only screen and (min-width: 1400px) and (max-width: 4000px) {
    .page-intro h1 {
        font-size: 60px;
        line-height: 70px;
        font-weight: bold;
        color: #fff;
        margin: 0 0 10px 0;
    }

    .page-intro {
        height: 650px;
    }

    .small-intro {
        height: 300px;
    }

}

@media only screen and (min-width: 767px) and (max-width: 991px)  {

}       

@media only screen and (min-width: 0px) and (max-width: 767px)  {

    .nav-btn {
        z-index: 10000;
        width: 36px;
        height: 42px;
        cursor: pointer;
        position: relative;
        margin: 25px 5px 0 0;
        display: block;
        padding-right: 35px;
    }

    .nav-btn span {
        display: block;
        border-radius: 20%;
        height: 4px;
        background-color: #3c5a5d;
        position: absolute;
        right: 0;
        top: 0;

        -webkit-transform: rotate(0deg);
        -moz-transform: rotate(0deg);
        -o-transform: rotate(0deg);
        transform: rotate(0deg);

        -webkit-transition: .1s ease-in-out;
        -moz-transition: .1s ease-in-out;
        -o-transition: .1s ease-in-out;
        transition: .1s ease-in-out;

        -webkit-transform-origin: left center;
        -moz-transform-origin: left center;
        -o-transform-origin: left center;
        transform-origin: left center;
    }

    .nav-btn span:nth-child(1) {width:100%;}
    .nav-btn span:nth-child(2) {width:100%; top: 7px;}
    .nav-btn span:nth-child(3) {width:100%; top: 14px;}

    .nav-btn:hover span:nth-child(2) {width: 100%;}
    .nav-btn:hover span:nth-child(3) {width: 100%;}

    .nav-btn.open {transition-duration: .3s;}
    .nav-btn.open span {box-shadow: none; background-color: #3c5a5d; right: -5px;}

    .nav-btn.open span:nth-child(1) {width:100%; transform: rotate(45deg); top: -3px;}
    .nav-btn.open span:nth-child(2) {opacity: 0;}
    .nav-btn.open span:nth-child(3) {width:100%; transform: rotate(-45deg); top: 22px;}

    nav {
        height: 0;
        overflow: hidden;
    }

    nav.open {
        height: 100%;
    }

}