main.css

body {
    background-color: #cdcdcd;
}

header {
    text-align: center;
    padding-top: 35px;
}

article {
    display: block;
    width: 95%;
    float: center;
    margin-left: auto;
    margin-right: auto;
}

article p {
    text-align:justify;
}

@media screen and (max-width: 800px) {
    aside#links {
        width: 85%;
        padding: 0;
    }
}

main {
    padding-left: 50px;
    padding-right: 50px;
}

/* Clear floats after the main body */
main:after {
    content: "";
    display: table;
    clear: both;
}

/************************************************
 *   Navigation bar
 */

nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1;
}

nav ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background-color: #606060;
}

nav li {
    float: left;
}

nav img {
    margin: -5px 0px;
}

nav li a, nav .dropbtn {
    display: inline-block;
    color: white;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
}

nav li a:hover:not(.active), nav .dropdown:hover .dropbtn {
    background-color: #3e0202;
}

nav .active {
    background-color: #023e02;
}

nav li.dropdown {
    display: inline-block;
}

nav .dropdown-content {
    display: none;
    position: absolute;
    background-color: #e9e9e9;
    min-width: 160px;
    box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
    z-index: 2;
    right: 0;
}

nav .dropdown-content a {
    color: black;
    padding: 12px 16px;
    text-decoration: none;
    display: block;
    text-align: left;
}

nav li .dropdown-content a:hover {
    background-color: #b27588;
}

nav .dropdown:hover .dropdown-content {
    display: block;
}

/************************************************
 *   Publications
 */

ol.publications-list {
    margin: 5px 40px;
    padding-top: 15px;
}

ol.publications-list li {
    padding: 7px 0px;
}

ul.selector {
    list-style-type: none;
    margin: auto;
    padding: 0;
    width: 450px;
    overflow: hidden;
    background-color: #606060;
}

ul.selector li {
    float: left;
    display: inline-block;
    color: white;
    text-align: center;
    width: 150px;
    padding: 10px 0px;
    text-decoration: none;
}

ul.selector li:hover:not(.active) {
    background-color: #3e0202;
}

ul.selector li.active {
    background-color: #023e02;
}


/************************************************
 *   Footer
 */

footer {
    margin: auto;
    background-color: grey;
    color: white;
    padding: 2px;
    margin-top: 10px;
    font-size: small;
    text-align: center;
    display: block;
    width: 50%;
}

footer p {
    padding: 0px;
    margin: 5px 0px;
}