sanic/static/flexbox/treeview.css

/* https://iamkate.com/code/tree-views/ */

/* Custom properties */

.tree {
  --spacing : 1.0rem;
  --radius  : 10px;
}

/* Padding */

.tree li {
  display      : block;
  position     : relative;
  padding-left : calc(2 * var(--spacing) - var(--radius) - 2px + 10px);
}

.tree ul {
  margin-left  : calc(var(--radius) - var(--spacing));
  padding-left : 0;
}

/* Vertical lines */

.tree ul li {
  border-left : 2px solid #ddd;
}

.tree ul li:last-child {
  border-color : transparent;
}

/* Horizontal lines */

.tree ul::before {
  content      : '';
  display      : block;
  position     : absolute;
  top          : calc(var(--spacing) - 8px);
  left         : 6px;
  width        : calc(var(--spacing) + 2px);
  border       : solid #ddd;
  border-width : 0 0 2px 2px;
}

.tree ul li::before {
  content      : '';
  display      : block;
  position     : absolute;
  top          : calc(var(--spacing) - 22px);
  left         : -2px;
  width        : calc(var(--spacing) + 2px);
  height       : calc(var(--spacing) - 2px);
  border       : solid #ddd;
  border-width : 0 0 2px 2px;
}

/* Summaries */

.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;
}

/* Markers */

.tree li::after,
.tree summary::before {
  content       : '\1F4C1';
  display       : block;
  position      : absolute;
  top           : calc(var(--spacing) / 1.5 - var(--radius));
  left          : calc(var(--spacing) - var(--radius) - 1px);
  width         : calc(2 * var(--radius));
  height        : calc(2 * var(--radius));
}u

/* Expand and collapse buttons */

.tree summary::before {
  z-index: 1;
  content: '\1F4C1';
}

.tree details[open] > summary::before {
  content: '\1F4C2';
}