:root {
    --header-height: 70px;
    --header-bg: linear-gradient(#5d5d5d, #e3e1e2);
    --header-fg: #eee;
    --header-fg-accent: #fff;
}

body, div, nav, main {
    min-height: 0;
    margin: 0;
    padding: 0;
    color: #222;
}

body {
    display: flex;
    flex-direction: column;
    align-items: stretch;
    background: var(--header-bg);
    overflow: hidden;
    height: 100vh;
	font-family: Arial, sans-serif;
	font-size: 17px;
	font-weight: 400;
	line-height: 1.5;
}

header, nav.site-nav {
    flex: 0 0 auto;
    font-weight: bold;
    font-size: 1.2em;
}
header a, nav.site-nav a {
    color: var(--header-fg);
}
nav.site-nav a {
    color: var(--header-fg);
    line-height: 150%;
}
header {
    flex: 0 0 var(--header-height);
    display: flex;
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
}
header a {
    text-decoration: none;
}

div.columns {
    flex: 1 1 auto;
    display: flex;
    flex-direction: row;
    justify-content: center;
}

header .nav-link img {
	max-width: 40px;
	max-height: 40px;
	margin: 0 10px;
}
.nav-link span {
	margin: 0 5px;
}
nav.site-nav {
    display: flex;
    flex-direction: row;
    overflow-y: auto;
    padding: 10px 20px;
}
.columns .center {
    flex: 0 1 800px;
    background: #fff;
    padding: 20px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
}
main {
    flex: 1 0 auto;
}
footer {
    flex: 0 0 auto;
    display: flex;
    flex-direction: row;
    align-items: center;
    justify-content: space-around;
    margin: 50px 0 10px 0;
}
nav.page-toc {
    flex: 0 0 200px;
    background: #fff;
    padding: 20px 20px 20px 10px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}
aside.nav-icons {
    display: flex;
    flex-direction: column;
    justify-content: center;
}
aside.nav-icons .nav-link img {
	max-width: 30px;
	max-height: 30px;
	margin: 10px;
}

nav.site-nav li {
    display: block;
}
nav.site-nav li a {
    text-decoration: none;
}
nav.site-nav li.selected a, nav.site-nav li:has(li.selected) > a {
    text-decoration: underline;
    color: var(--header-fg-accent);
}
.search-opener, .previous-page-link, .next-page-link {
	opacity: 0.75;
}
.search-opener:hover, .previous-page-link:hover, .next-page-link:hover {
	opacity: 1;
}
.nav-link.unexpanded,  .nav-link.unexpanded:hover {
	opacity: 0.1;
}

div.page-title {
    text-align: center;
    font-size: 2em;
    font-weight: bold;
    margin: 20px 0 80px 0;
}

.page-toc .toc-title {
    display: none;
}

@media (min-width: 768px) { /* wide screens */
	#nav-toggle, .nav-toggle-label { /* hide hamburger on wide screens */
		display: none;
	}
}