:root {
  color-scheme: light;
  --ink: #111412;
  --muted: #5e6761;
  --paper: #f6f8f6;
  --surface: #ffffff;
  --line: #d9e0dc;
  --line-strong: #9fafaa;
  --accent: #08795f;
  --accent-strong: #045842;
  --danger: #b23b48;
  --code: #111a16;
  --code-bg: #edf3ef;
  --shadow: 0 18px 44px rgba(17, 20, 18, 0.08);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  background: var(--paper);
  color: var(--ink);
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  line-height: 1.5;
  letter-spacing: 0;
}

button,
textarea,
input {
  font: inherit;
  letter-spacing: 0;
}

a {
  color: var(--accent-strong);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

.shell {
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
  padding: 32px 0 56px;
}

.workspace {
  padding: 24px 0 0;
}

.intro {
  max-width: 780px;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--accent-strong);
  font-size: 0.82rem;
  font-weight: 750;
  text-transform: uppercase;
}

h1,
h2,
p {
  overflow-wrap: anywhere;
}

h1 {
  margin: 0;
  font-size: 5rem;
  line-height: 0.95;
  letter-spacing: 0;
}

h2 {
  margin: 0;
  font-size: 1rem;
  line-height: 1.2;
}

.lede {
  max-width: 680px;
  margin: 16px 0 0;
  color: var(--muted);
  font-size: 1.08rem;
}

.tool-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 20px;
  margin-top: 32px;
  align-items: stretch;
}

.editor,
.results,
.output-panel,
.paper-figure,
.tree-section,
.notes {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.editor {
  display: grid;
  gap: 14px;
  padding: 18px;
}

label {
  color: var(--muted);
  font-size: 0.9rem;
  font-weight: 700;
}

textarea {
  min-height: 168px;
  width: 100%;
  resize: vertical;
  border: 1px solid var(--line-strong);
  border-radius: 6px;
  padding: 16px;
  background: var(--code-bg);
  color: var(--code);
  font-family: "Cascadia Code", "SFMono-Regular", Consolas, monospace;
  font-size: 1rem;
  line-height: 1.55;
}

textarea:focus-visible,
button:focus-visible,
input:focus-visible {
  outline: 3px solid rgba(8, 121, 95, 0.32);
  outline-offset: 2px;
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 16px;
  align-items: center;
}

button {
  min-height: 42px;
  border: 1px solid var(--line-strong);
  border-radius: 6px;
  padding: 0 14px;
  background: var(--surface);
  color: var(--ink);
  cursor: pointer;
  transition:
    transform 160ms ease,
    border-color 160ms ease,
    background 160ms ease;
}

button:hover {
  border-color: var(--accent);
  transform: translateY(-1px);
}

button[type="submit"] {
  border-color: var(--accent);
  background: var(--accent);
  color: #ffffff;
  font-weight: 750;
}

button[type="submit"]:hover {
  background: var(--accent-strong);
}

.check {
  display: inline-flex;
  gap: 8px;
  align-items: center;
  min-height: 42px;
  color: var(--ink);
  font-weight: 600;
}

.check input {
  width: 18px;
  height: 18px;
  accent-color: var(--accent);
}

.hint,
.notes p,
.tree-section p,
figcaption {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.results {
  display: grid;
  gap: 18px;
  padding: 18px;
}

.status-line {
  min-height: 48px;
  border-left: 4px solid var(--accent);
  padding: 11px 0 0 14px;
  color: var(--accent-strong);
  font-weight: 750;
  transition: background 220ms ease;
}

.status-line.error {
  border-left-color: var(--danger);
  color: var(--danger);
}

.status-line.flash {
  background: rgba(8, 121, 95, 0.1);
}

.metrics {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin: 0;
}

.metrics div {
  min-width: 0;
  border-top: 1px solid var(--line);
  padding-top: 12px;
}

.metrics dt {
  color: var(--muted);
  font-size: 0.78rem;
}

.metrics dd {
  margin: 4px 0 0;
  font-size: 1.6rem;
  font-weight: 780;
  font-variant-numeric: tabular-nums;
}

.outputs {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin-top: 16px;
}

.output-panel {
  min-width: 0;
  overflow: hidden;
}

.output-panel.wide {
  grid-column: 1 / -1;
}

.panel-head {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
  min-height: 58px;
  border-bottom: 1px solid var(--line);
  padding: 0 14px 0 16px;
}

.copy {
  min-height: 34px;
  padding: 0 11px;
  font-size: 0.86rem;
}

pre {
  min-height: 124px;
  max-height: 430px;
  margin: 0;
  padding: 16px;
  overflow: auto;
  background: var(--code-bg);
  color: var(--code);
  font-family: "Cascadia Code", "SFMono-Regular", Consolas, monospace;
  font-size: 0.9rem;
  line-height: 1.55;
  white-space: pre-wrap;
  word-break: break-word;
}

.reference {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 340px;
  gap: 16px;
  margin-top: 16px;
  align-items: start;
}

.reference > div {
  min-width: 0;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.examples {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 14px;
}

.examples button {
  font-family: "Cascadia Code", "SFMono-Regular", Consolas, monospace;
  font-size: 0.9rem;
}

.paper-figure {
  margin: 0;
  padding: 12px;
}

.paper-figure img {
  display: block;
  width: 100%;
  max-height: 260px;
  object-fit: contain;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #ffffff;
}

.paper-figure figcaption {
  margin-top: 10px;
}

.tree-section {
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  gap: 18px;
  margin-top: 16px;
  padding: 18px;
}

.tree-copy {
  display: grid;
  align-content: start;
  gap: 16px;
}

.tree-depth-control {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
  color: var(--ink);
}

.tree-depth-control span {
  display: inline-grid;
  place-items: center;
  min-width: 32px;
  height: 26px;
  border: 1px solid var(--line);
  border-radius: 6px;
  color: var(--accent-strong);
  font-variant-numeric: tabular-nums;
}

#tree-depth {
  width: 100%;
  accent-color: var(--accent);
}

.tree-preview {
  min-height: 330px;
  overflow: auto;
  padding: 14px;
  border: 1px solid var(--line-strong);
  border-radius: 6px;
  background: #fbfcfb;
  cursor: grab;
  overscroll-behavior: contain;
}

.tree-preview:active {
  cursor: grabbing;
}

.tree-svg {
  display: block;
  min-width: 100%;
}

.tree-edge {
  stroke: var(--line-strong);
  stroke-width: 1.5;
  stroke-linecap: round;
}

.tree-node-shape {
  fill: var(--surface);
  stroke: var(--line-strong);
  stroke-width: 1.2;
  filter: drop-shadow(0 5px 10px rgba(17, 20, 18, 0.06));
}

.tree-node-shape.operator {
  fill: #eef8f5;
  stroke: var(--accent);
}

.tree-node-shape.clipped {
  stroke-dasharray: 4 4;
}

.tree-node-label {
  fill: var(--ink);
  font-family: "Cascadia Code", "SFMono-Regular", Consolas, monospace;
  font-size: 12px;
  font-weight: 750;
  text-anchor: middle;
  dominant-baseline: middle;
}

.tree-node-label.operator {
  fill: var(--accent-strong);
}

.tree-node-note {
  fill: var(--muted);
  font-family: "Cascadia Code", "SFMono-Regular", Consolas, monospace;
  font-size: 10px;
  text-anchor: middle;
}

.tree-empty {
  color: var(--muted);
  min-height: 300px;
  display: grid;
  place-items: center;
  text-align: center;
}

.notes {
  display: grid;
  gap: 12px;
  margin-top: 16px;
  padding: 18px;
}

@keyframes settle {
  from {
    opacity: 0;
    transform: translateY(4px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 1ms !important;
    scroll-behavior: auto !important;
    transition-duration: 1ms !important;
  }
}

@media (max-width: 860px) {
  .shell {
    width: min(100% - 20px, 720px);
    padding-top: 10px;
  }

  .workspace {
    padding-top: 12px;
  }

  h1 {
    font-size: 3.6rem;
  }

  .tool-grid,
  .outputs,
  .reference,
  .tree-section {
    grid-template-columns: 1fr;
  }

  .metrics {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .tree-section {
    padding: 16px;
  }
}

@media (max-width: 520px) {
  h1 {
    font-size: 2.28rem;
  }

  .controls {
    align-items: stretch;
    flex-direction: column;
  }

  button[type="submit"] {
    width: 100%;
  }

  .metrics {
    grid-template-columns: 1fr;
  }

  .panel-head {
    align-items: flex-start;
    flex-direction: column;
    padding: 14px;
  }

  .copy {
    width: 100%;
  }
}