html, body, main {
    height: 100%;
}
.screen-reader {
    position:absolute;
    left:-10000px;
    top:auto;
    width:1px;
    height:1px;
    overflow:hidden;
}
body {
    max-width: 100rem;
    margin: 0 auto;
    font-family: sans-serif;
}
div.devheader {
    display: flex;
    border: 1px solid black;
    background-color: red;
    padding: 1rem;
    color: white;
    font-size: 16pt;
    justify-content: center;
}
main {
    padding: 1rem;
    background-image: linear-gradient(to bottom, lavender, white);
    background-size: 100% 500px;
    background-repeat: no-repeat;
    min-height: 500px;
}
h1 {
    margin-top: 0;
}
.smalltext {
    font-size: smaller;
}

/* START NAV RULES */
nav {
    display: block;
    border: 1px solid black;
    background-color: purple;
    padding: 1rem;
}
nav a {
    color: white;
    text-decoration: none;
}
nav .nav-brand {
    font-size: 20pt;
    margin: 0.5rem;
}
nav .nav-link {
    font-size: 12pt;
    margin: 0.5rem;
}
/* END NAV RULES */

/* START BUTTON RULES */
button, a.button {
    border: 1px solid purple;
    border-radius: 5px;
    padding: 0.4em;
    margin: 0.4em;
    text-decoration: none;
    background-color: lavender;
    color: purple;
    height: 1.5em;
    max-height: 1.5em;
    font-size: 12pt;
    display: inline-block;
}
button.a {
    box-sizing: border-box;
}
button {
    box-sizing: content-box;
}
button:hover, a.button:hover {
    opacity: 0.5;
    cursor: pointer;
}
button.button-red, a.button-red {
    border-color: red !important;
    background-color: pink !important;
    color: red !important;
}
button:disabled {
    opacity: 0.5;
    pointer-events: none;
}
button.toggle {
    visibility: none; // Show with javascript
}
/* END BUTTON RULES */

/* START DATA-TABLE RULES */
.data-table {
    border-collapse: collapse;
    width: 100%;
}
.data-table thead {
    position: sticky;
    top: 0px;
    background-color: darkgray;
    z-index: 1;
}
.data-table th {
    padding: 0.5rem;
}
.data-table td {
    padding: 0.5rem;
    max-width: 40rem;
}
.data-table tr:nth-child(odd) {
    background-color: lightgray;
}
.data-table p {
    white-space: pre-line;
    margin: 0;
}
/* END DATA-TABLE RULES */

/* START INPUT-TABLE RULES */
.input-table {
    margin: 1em;
    border-collapse: collapse;
}
.input-table th, .input-table td {
    padding: 0.2em 0.5em;
    vertical-align: top;
}
.input-table input, .input-table select {
    margin: 0.2em;
    padding: 0.2em;
}
.input-table p {
    white-space: pre-line;
    margin: 0;
}
/* END INPUT-TABLE RULES */

/* START DIFFICULTY RULES */
.diff-0 {
    background-color: #FFFFFF;
}
.diff-1 {
    background-color: #99FF33;
}
.diff-2 {
    background-color: #FFFF33;
}
.diff-3 {
    background-color: #FF9933;
}
.diff-4 {
    background-color: #F50000;
}
.diff-99 {
    background-color: #FFC0CB;
}
/* END DIFFICULTY RULES */