* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

a {
    color: black;
    text-decoration: none;
}

.error {
    color: red;
    font-weight: bold;
}

.null-val {
    font-style: italic;
}

html,
body {
    height: 100%;
    text-align: center;
}

#content {
    display: flex;
    flex-flow: column;
    height: 100%;
}

header, footer, nav {
    background: #333;
    padding: 10px;
    color: white;
}
header a, footer a, nav a {
    color: white;
}

header .logout {
    float: right;
    text-align: right;
}

nav {
    border-top: 2px solid #555;
}
nav ul, section .nav {
    display: flex;
    justify-content: space-around;
    padding: 0 10%;
    list-style: none;
}

section {
    flex: 1;
    margin: 20px;
    height: 100%;
    display: flex;
    flex-direction: column;
}
section a {
    text-decoration: underline;
    text-decoration-style: dotted;
}
section p {
    margin: 5px;
}
section a:hover {
    text-decoration-style: dashed;
}
section table{
    margin: 20px auto;
    border-collapse: collapse;
}
section td, section th {
    border: 1px solid black;
    padding: 2px 5px;
}
section label {
    display: inline-block;
    min-width: 10%;
    text-align: right;
    padding: 2px;
}
section [type="submit"] {
    padding: 2px 10px;
}
section .nav{
    flex: 1;
    display: flex;
    flex-direction: column;
}
section .nav:before{ 
    content: "";
    flex: 1;
}