html,
body {
    height: 100%;
}
body {
    font: 1.1rem/1.5 "Helvetica", "Helvetica Neue", "Arial", "sans-serif";
    margin: 0 auto;
    hyphens: auto;
}
.header-menu,
footer {
    display: flex;
    align-items: center;
    width: 100%;
}
.header-menu {
    height: 125px;
    background-color: white;
}
.navbar {
    display: flex;
    justify-content: space-evenly;
    align-items: center;
    width: 100%
}
.logo {
    display: inline-block;
}
.logo img {
    width: 12em;
    vertical-align: center;
}
.navlinks {
    display: flex;
    list-style: none;
}
.nav-item a {
    display: inline-block;
    font-size: 1.2em;
    color: dimgrey;
    padding: 0 10px;
}
.nav-item a:link,
.nav-item a:visited {
    text-decoration: none;
}
.nav-item a:hover {
    text-decoration: underline;
}
main {
    display: flex;
    flex: 0.6;
    width: 100%;
}
article {
    margin: 0 30em 0 30em;
}
article h1 {
    font-size: 1.75em;
}
article h2 {
    font-size: 1.25em;
}
article h3 {
    font-size: 1em;
}
figure img {
    width: 47em;
}
button {
    box-shadow: 0 8px 16px 0 rgba(0,0,0,0.2), 0 6px 20px 0 rgba(0,0,0,0.19);
    background: black;
    border: 0.5px solid black;
    border-radius: 10px;
    display: inline-block;
    padding: 0.5em;
    text-align: center;
    text-decoration: none;
    font-size: 1em;
}
button a {
    color: whitesmoke;
    text-decoration: none;
}
details {
    margin-bottom: 1em;
}

details .title {
    font-size: 1.1em;
    font-weight: bold;
}

details .authors {
    font-size: 1.1em;
    font-style: italic;
}
.toc {
    display: block;
    position: fixed;
    top: 15%;
    left: 10%;
    width: 15em;
    font-size: smaller;
}
.toc h1 {
    font-size: 1.2em;
    color: white;
    background-color: black;
    padding: 0.5em 0 0.5em 0.5em;
}
.toc h1 > a {
    color: white;
    background-color: black;
}
.toc ol {
    padding-left: 0;
    list-style: none;
}
.toc li {
    font-size: 1.2em;
    padding: 0.25em 0 0.25em 0.5em;
}
.toc li:hover {
    background-color: lightgray;
}
.toc a {
    color: gray;
    text-decoration: none;
}
footer {
    flex: 1;
    padding: 20px 0 50px 0;
    background-color: black;
    color: white;
}
footer p {
    width: 100%;
    text-align: center;
}
footer a:link,
footer a:visited {
    color: white;
    text-decoration: none;
}
footer a:hover {
    text-decoration: underline;
}