:root {
    --base-color: #444;
    --predet-green: rgb(220, 229, 211);
    --predet-blue: rgb(225, 230, 237);
    --predet-pink: rgb(232, 216, 224);
    --predet-orange: rgb(232, 220, 216);
    --predet-yellow: rgb(229, 228, 211);
}

body {
    padding: 0;
    margin: 0;
    font-family: Helvetica, sans-serif;
    color: var(--base-color);
    line-height: 1.5;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: normal;
}

header {
    background: linear-gradient(to bottom, rgb(171, 175, 189), rgb(210, 210, 210));
    padding-top: 5px;
    border-top: 1px solid black;
    border-bottom: 1px solid black;
    padding-bottom: 4px;
}

main {
    position: absolute;
    top: 125px;
    bottom: 0;
    left: 0;
    right: 0;
    background: linear-gradient(to bottom, rgb(227, 230, 233), rgb(245, 246, 247));
}

nav ul {
    display: flex;
    gap: 15px;
    list-style-type: none;
    font-size: 14px;
    margin: 0;
    padding-left: 0;
}

nav ul li a {
    color: var(--base-color);
    padding: 7px;
    border-top-left-radius: 10px; 
    border-top-right-radius: 10px; 
    border-top: 1px solid transparent;
    border-left: 1px solid transparent;
    border-right: 1px solid transparent;
    text-decoration: none;
    text-decoration: none;
}

nav ul li a:hover {
    border-top: 1px solid #aaa;
    border-left: 1px solid #aaa;
    border-right: 1px solid #aaa;
    color: var(--base-color);
    text-decoration: none;
}

p {
    margin: 0;
}

.center-content {
    width: 900px;
    padding: 10px 20px;
    font-size: 14px;
}

.center-content h1 {
    margin: 0;
    margin-bottom: 15px;
    font-size: 20px;
}

.center-content h2 {
    font-weight: bold;
    font-size: 16px;
    margin: 7px 0 5px 0;
}

.center-content p {
    margin-bottom: 10px;
}

.centered {
    width: 1400px;
    margin: auto;
}

.external-links {
    list-style-type: none;
    padding-left: 0;
    font-size: 0.8rem;
}

.external-links li {
    margin-bottom: 10px;
}

footer {
    display: flex;
    flex-direction: column;
    justify-content: end;
    align-items: center;
    text-align: center;
    border-top: 1px solid #eee;
    margin-top: 50px;
    padding-top: 10px;
    font-weight: bold;
    color: #777;
}

.link {
    text-decoration: none;
    color: rgb(63, 114, 141);;
}

.link:hover {
    color: rgb(63, 100, 130);
}

ol.faq li {
    font-weight: bold;
}

ol.faq ul li {
    font-weight: normal;
}

ul.pub-list li {
    margin-bottom: 15px;
}

.side-left {
    width: 200px;
    font-size: 12px;
}

.side-left h2 {
    font-size: 18px;
    padding-right: 10px;
    margin-bottom: 0;
}

.side-left > div {
    padding-right: 20px;
    margin-bottom: 20px;
}

ul.site-list li {
    margin-bottom: 10px;
}

table.study-staff {
    border-collapse: collapse;
}

table.study-staff td {
    border: 1px solid black;
    padding: 10px;
}

table.for-ppts {
    border-collapse: collapse;
    font-size: 14px;
}

table.for-ppts td {
    border: 1px solid #aaa;
    padding: 5px;
}