body {
    color: #fff;
}
.header {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
}
.container {
    max-width: 1200px;
    margin: 0 auto;
}
.logo {
    margin-top: 50px;
    margin-bottom: 30px;
    width: 200px;
}
.button-center {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
}
button {
    background-color: #3498db;
    color: #fff;
    border: none;
    padding: 10px 20px;
    font-size: 16px;
}
button:hover {
    background-color: #2980b9;
}
pre {
    white-space: pre-wrap;
}
#footer {
    position: fixed;
    bottom: 10px;
    right: 10px;
    background-color:#263745;
    padding: .2em;
    opacity: 0.4;
}
/* Yet unused, from https://iamkate.com/code/tree-views/ */
/* .tree{
    --spacing : 1.5rem;
    --radius : 10px;
}
.tree li{
    display : block;
    position : relative;
    padding-left : calc(2 * var(--spacing) - var(--radius) - 2px);
}
.tree ul{
    margin-left : calc(var(--radius) - var(--spacing));
    padding-left : 0;
}
.tree ul li{
    border-left : 2px solid #ddd;
}
.tree ul li:last-child{
    border-color : transparent;
}
.tree ul li::before{
    content : '';
    display : block;
    position : absolute;
    top : calc(var(--spacing) / -2);
    left : -2px;
    width : calc(var(--spacing) + 2px);
    height : calc(var(--spacing) + 1px);
    border : solid #ddd;
    border-width : 0 0 2px 2px;
}
.tree summary{
    display : block;
    cursor : pointer;
}
.tree summary::marker, .tree summary::-webkit-details-marker{
    display : none;
}
.tree summary:focus{
    outline : none;
}
.tree summary:focus-visible{
    outline : 1px dotted #000;
}
.tree li::after, .tree summary::before{
    content : '';
    display : block;
    position : absolute;
    top : calc(var(--spacing) / 2 - var(--radius));
    left : calc(var(--spacing) - var(--radius) - 1px);
    width : calc(2 * var(--radius));
    height : calc(2 * var(--radius));
    border-radius : 50%;
    background : #ddd;
}
.tree summary::before{
    content : '+';
    z-index : 1;
    background : #696;
    color : #fff;
    line-height : calc(2 * var(--radius) - 2px);
    text-align : center;
}
.tree details[open] > summary::before{
    content : '−';
} */