header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    transition: background-color .5s;
}

header a.logo {
    display: inline-block;
    width: 300px;
    max-width: 70%;
    padding: 10px 0;
}

header nav .nav a {
    text-decoration: none;
    display: inline-block;
    padding: 10px 20px;
    font-weight: bold;
}
header nav a{
    color:var(--blue);
    cursor: pointer;
}
header nav a:hover{
    color:var(--yellow);
    cursor: pointer;
}

header:not(.top) {
    background-color: #FFF;
    box-shadow: 0  5px 5px 0 #0001;
    z-index: 2;
}
header a.logo img:last-child {
    transition: filter .5s;
}

header.top a.logo img:last-child {
    filter: invert(100%);
}

header.top nav a{
    color:var(--white);
    text-shadow: 0  5px 5px 0 #0001;
}

header.top nav a:hover {
    color: var(--yellow);
    text-shadow: none;
}

picture.header {
    position: relative;
    z-index: -1;
}

picture.header img {
    filter: brightness(70%);
}
a.button.orange {
    padding: 10px 25px;
    background-color: var(--orange);
    color: var(--white);
    transition: background-color .3s;
    border-radius: 25px;
    text-decoration: none;
}

a.button.orange:hover {
    background-color: var(--white);
    color: var(--orange);
    cursor: pointer;
}


/* Mobile & Tablet */
@media (max-width: 819.999px) {
     header a.logo {
        padding-left: 10px;
    }
    header.top nav a{
        color:var(--blue);
        text-shadow: 0  5px 5px 0 #0001;
    }
    header .logo img{
        max-width: 60%;
    }
    .nav header nav{
        padding: 10px;
    }
    header a.logo img:last-child {
    transition: filter .5s;
    }

    header.top a.logo img:last-child {
        filter: invert(100%);
    }
}

@media (max-width: 979.999px) {
    header .mgE {
        float: right;
    }

    header {
        transition: background-color .5s;
    }

    /* body:not(.nav) header {
        background-color: transparent;
    } */

    body.nav header {
        background-color: #FFF;
    }

    header section > nav {
        text-align: center;
        background-color: var(--fill);
        overflow: hidden;
        height: 0;
        transition: height .5s;
    }

    body.nav header nav {
        overflow-y: auto; /* скрол по вертикала */
        height: calc(100vh - 84px);
    }

    header nav .nav div {
        margin: 10px 0;
    }
}

/* Desktop */
@media (min-width: 980px) {
    section {
        padding: 10px 40px;
        box-sizing: border-box;
    }

    header .mgE {
        display: none;
    }

    header nav {
        float: right;
        width: calc(100% - 300px);
        padding: 25px 0px;
    }

    header nav > a.button:first-child { /* INFO: Contact Us */
        float: right;
    }

    header nav .nav {
        margin-right: 160px;
        text-align: center;
    }

    header nav .nav div {
        display: inline-block;
    }
    
}

/* picture */
picture.header {
    display: block;
    max-height: 90vh;
    overflow: hidden;
}

picture.header img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    max-height: 100vh;
}
/* <<< */