html, body {
    max-width: 100%;
    margin: 0;
    padding: 0;
}

* {
    box-sizing: border-box;
}

body {
    font-family: sans-serif;
}

/* --- Header --- */
header {
    margin: 1em;
    display: flex;
    justify-content: space-between;
    align-content: center;
    align-items: center;
}

header h1 {
    margin: 1em;
}

/* --- Navigation bar --- */
nav {
}

nav ul {
    display: flex;
    margin: -1px 0 0 0;
    padding: 0 1.5em;
    border: 0;
    border-bottom: 1px solid #000000;
}

nav ul li {
    margin: 0 0 -1px -1px;
    list-style: none;
    z-index: 1;
}

nav a {
    display: block;
    width: 100%;
    height: 100%;
    padding: 0.5em 1em;
    border: 1px solid #999999;
    border-bottom-color: #000000;
}

nav a:link, nav a:visited {
    background-color: #eeeeee;
    color: blue;
    text-decoration: none;
}

nav a:hover, nav a:focus {
    background-color: #ffffff;
    text-decoration: underline;
}

nav li.nav_current_page {
    z-index: 10;
}

nav li.nav_current_page a {
    background-color: #ffffff;
    border-color: #000000;
    border-bottom-color: #ffffff;
}

/* --- Main section --- */
main {
    margin: 2em;
}

/* --- Login page --- */
main.login_page {
    margin: 2em;
    padding: 1em;
    border: 1px solid #666666;
}

main.login_page table td {
    padding: 0.2em;
}

/* --- Text and other styling --- */
h2 {
    margin: 0 0 0.5em 0;
}

.error {
    background: #ff4444;
    width: 30em;
    margin: 1em 0;
    padding: 1em;
}

button {
    padding: 0.2em 1em;
}