.header, .footer {
    left: 0;
    right: 0;
    z-index: 999;
    color: whitesmoke;
    text-align: center;
}

.header {
    top: 0;
    border-bottom: 1px solid whitesmoke;
    position: sticky;
}

.footer {
    bottom: 0;
    border-top: 1px solid whitesmoke;
    background-color: rgba(0, 0, 0, 0.8);
    font-family: Calibri, sans-serif;
}

.footer .copy {
    font-size: 17px;
    padding: 14px 16px;
    display: block;
}

.nav {
    overflow: hidden;
    background-color: rgba(0, 0, 0, 0.8);
    font-family: Calibri, sans-serif;
}

.nav a {
    float: right;
    display: block;
    color: whitesmoke;
    text-align: center;
    text-decoration: none;
    font-size: 17px;
    padding: 13px 16px;
    border-left: 1px dashed;
}

.nav .main_title {
    float: left;
    font-size: 23px;
    font-weight: bold;
    padding: 10px 16px;
}

.nav a:hover {
    background-color: rgba(0, 76, 153, 0.5);
    color: whitesmoke;
}

.nav a:active {
    background-color: rgba(245, 254, 254, 0.5);
    color: black;
}

/* nav responsive */

.nav .icon {
    display: none;
}

.hamburger {
    display: inline-block;
    cursor: pointer;
}

.bar1, .bar2, .bar3 {
    width: 25px;
    height: 2px;
    background-color: whitesmoke;
    margin: 6px 0;
    transition: 0.4s;
}

/* Rotate first bar */
.change .bar1 {
    transform: translate(0, 8px) rotate(-45deg);
}

/* Fade out the second bar */
.change .bar2 {opacity: 0;}

/* Rotate last bar */
.change .bar3 {
    transform: translate(0, -8px) rotate(45deg);
}

/* When the screen is less than 700 pixels wide, hide all links, except for the first one ("Home"). Show the link that contains should open and close the topnav (.icon) */
@media screen and (max-width: 700px) {
    .nav a {display: none;}
    .nav a.icon {
        float: right;
        display: block;
        border: none;
    }
}

/* The "responsive" class is added to the nav with JavaScript when the user clicks on the icon. This class makes the topnav look good on small screens (display the links vertically instead of horizontally) */
@media screen and (max-width: 700px) {
    .nav.responsive {
        position: relative;
    }
    .nav.responsive a.icon {
        right: 0;
        top: 0;
    }
    .nav.responsive a {
        float: none;
        display: block;
        text-align: right;
        border: none;
    }
}