/* treegen — tool chrome.
 *
 * Neutral greys, black hairlines and hard offset shadows, matching the site's
 * existing surfaces. Everything is left-aligned. Colour belongs to the tree,
 * not to the UI.
 */

#treegen {
  --tg-ink: #000;
  --tg-panel: #ccc;
  --tg-stage: #fff;
  --tg-hair: #000;
  --tg-muted: rgba(0, 0, 0, 0.55);
  --tg-shadow: 0.35rem 0.35rem 0 0 rgba(0, 0, 0, 1);

  max-width: 1180px;
  margin: 0 auto calc(var(--spacing-unit) * 2);
  padding: 0 var(--spacing-unit);
  text-align: left;
}

/* ---------- Header ---------- */

#tg-head {
  margin-bottom: var(--spacing-unit);
}

#tg-head h1 {
  font-size: var(--font-size-h2);
  line-height: 1;
}

.tg-version {
  font-size: var(--font-size-h6);
  font-weight: 200;
  letter-spacing: 0.02em;
  margin-left: 0.25rem;
  vertical-align: super;
}

.tg-sub {
  color: var(--tg-muted);
  margin-top: 0.25rem;
}

/* ---------- Toolbar ---------- */

.tg-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.45rem 0.8rem;
  padding: 0.6rem 0.7rem;
  background: var(--tg-panel);
  border: 1px solid var(--tg-hair);
  border-radius: 0.25rem;
  box-shadow: var(--tg-shadow);
}

.tg-group {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

/* Dashed rule separating each group, rather than a heavier divider. */
.tg-group + .tg-group {
  padding-left: 0.8rem;
  border-left: 1px dashed rgba(0, 0, 0, 0.45);
}

.tg-label {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: lowercase;
  color: var(--tg-muted);
}

.tg-btn {
  font-family: inherit;
  font-size: 0.8rem;
  font-weight: 600;
  line-height: 1;
  padding: 0.4rem 0.5rem;
  color: var(--tg-ink);
  background: var(--tg-stage);
  border: 1px solid var(--tg-hair);
  border-radius: 0.15rem;
  cursor: pointer;
}

.tg-btn:hover {
  background: var(--tg-ink);
  color: var(--tg-stage);
}

.tg-btn:active {
  transform: translate(1px, 1px);
}

/* The file input is hidden behind its own label, styled as a button. */
.tg-file {
  display: inline-flex;
  align-items: center;
}

.tg-file input[type='file'] {
  display: none;
}

#treegen select,
#treegen input[type='text'],
#treegen input[type='number'],
#treegen textarea {
  font-family: inherit;
  font-size: 0.8rem;
  padding: 0.35rem 0.4rem;
  color: var(--tg-ink);
  background: var(--tg-stage);
  border: 1px solid var(--tg-hair);
  border-radius: 0.15rem;
}

#tg-interval,
#tg-layers,
#tg-trunk {
  width: 2.9rem;
}

.tg-unit {
  font-size: 0.75rem;
  color: var(--tg-muted);
  margin-left: -0.2rem;
}

.tg-check {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.8rem;
  cursor: pointer;
}

.tg-readout {
  font-size: 0.75rem;
  padding: 0.3rem 0.4rem;
  color: var(--tg-muted);
  background: var(--tg-stage);
  border: 1px dashed rgba(0, 0, 0, 0.45);
  border-radius: 0.15rem;
  white-space: nowrap;
}

/* ---------- L-system disclosure ---------- */

#tg-lsys {
  margin-top: 0.6rem;
  border: 1px dashed rgba(0, 0, 0, 0.45);
  border-radius: 0.25rem;
  background: var(--tg-panel);
}

#tg-lsys > summary {
  padding: 0.45rem 0.75rem;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  cursor: pointer;
  list-style: none;
}

#tg-lsys > summary::before {
  content: '+ ';
  font-weight: 800;
}

#tg-lsys[open] > summary::before {
  content: '− ';
}

.tg-lsys-body {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: 0.75rem;
  padding: 0 0.75rem 0.75rem;
}

.tg-field {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--tg-muted);
}

.tg-field-wide {
  flex: 1 1 18rem;
}

.tg-field textarea {
  width: 100%;
  resize: vertical;
  font-family: ui-monospace, Menlo, Consolas, monospace;
  font-size: 0.75rem;
}

.tg-field input[type='number'] {
  width: 5rem;
}

/* ---------- Stage ---------- */

#tg-canvas {
  margin-top: 0.75rem;
  background: var(--tg-stage);
  border: 1px solid var(--tg-hair);
  border-radius: 0.25rem;
  box-shadow: var(--tg-shadow);
  overflow: hidden;
}

.tg-stage {
  display: block;
  width: 100%;
  height: auto;
  touch-action: none;   /* pointer drags shouldn't scroll the page */
  cursor: crosshair;
}

.tg-site {
  fill: rgba(0, 0, 0, 0.16);
  shape-rendering: crispEdges;
}

.tg-horizon-line {
  stroke: rgba(0, 0, 0, 0.55);
  stroke-width: 1;
  stroke-dasharray: 5 4;
}

.tg-branch {
  stroke: #3a3028;
  stroke-linecap: round;
  fill: none;
}

/* The trunk — the most central path — carries no vegetation, so it reads as
   bare wood. Slightly darker and blunt-ended to look structural. */
.tg-branch-trunk {
  stroke: #2b231c;
  stroke-linecap: butt;
}

/* Roots read lighter and dashed, so the structure below the horizon is
   legible without competing with the canopy. */
.tg-branch-root {
  stroke: #6b5c4a;
  stroke-dasharray: 3 3;
}

/* Node points are authoring chrome, not part of the drawing: invisible until
   you put the cursor on one. They keep their hit area either way, so the tree
   is grabbable everywhere without being peppered with dots. */
.tg-handle {
  fill: #fff;
  stroke: #000;
  stroke-width: 1;
  cursor: grab;
  opacity: 0;
  transition: opacity 90ms ease-out;
}

.tg-handle:hover,
.tg-handle:focus {
  opacity: 1;
}

/* The root is the horizon marker, so it stays visible. */
.tg-handle-root {
  fill: #000;
  stroke: #000;
  opacity: 1;
}

/* While a drag is in progress, show every point so you can see where the
   node may land. */
.tg-stage.is-dragging .tg-handle {
  opacity: 0.45;
}

/* Legal drag destinations. `is-hot` is the one that will be committed. */
.tg-target {
  fill: rgba(0, 0, 0, 0.08);
  stroke: rgba(0, 0, 0, 0.5);
  stroke-width: 1;
  stroke-dasharray: 2 2;
  pointer-events: none;
}

.tg-target.is-hot {
  fill: rgba(0, 0, 0, 0.35);
  stroke: #000;
  stroke-dasharray: none;
}

/* The only illegal drop is a point another node already holds. */
.tg-target.is-blocked {
  fill: none;
  stroke: #8a1c14;
  stroke-dasharray: 2 2;
}

/* ---------- Status ---------- */

.tg-status {
  min-height: 1.2rem;
  margin-top: 0.5rem;
  font-size: 0.78rem;
  color: var(--tg-muted);
}

.tg-status.is-error {
  color: #8a1c14;
  font-weight: 600;
}

/* ---------- Narrow screens ---------- */

@media (max-width: 720px) {
  .tg-group + .tg-group {
    padding-left: 0;
    border-left: 0;
  }

  .tg-bar {
    gap: 0.5rem 0.75rem;
  }
}