:root {
  --bg: #14161a;
  --panel: #1e2128;
  --text: #e6e6e6;
  --muted: #9aa0aa;
  --accent: #7aa2f7;
  --error: #f7768e;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
}

header {
  padding: 16px 24px 8px;
}

h1 {
  margin: 0;
  font-size: 1.4rem;
}

.subtitle {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.article-link {
  margin: 4px 0 0;
  font-size: 0.8rem;
}

.article-link a {
  color: var(--accent);
  text-decoration: none;
}

.article-link a:hover {
  text-decoration: underline;
}

main {
  display: flex;
  flex-direction: column;
  gap: 16px;
  padding: 8px 24px 24px;
}

#controls {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

#expr-input {
  font: 1rem ui-monospace, monospace;
  padding: 10px 12px;
  background: var(--panel);
  color: var(--text);
  border: 1px solid #333842;
  border-radius: 6px;
}

#expr-input:focus {
  outline: 1px solid var(--accent);
}

.buttons {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.presets {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

#variables-details {
  background: var(--panel);
  border: 1px solid #333842;
  border-radius: 6px;
  padding: 6px 10px;
}

#variables-details summary {
  cursor: pointer;
  color: var(--muted);
  font-size: 0.85rem;
  user-select: none;
}

#variables-details[open] summary {
  margin-bottom: 8px;
}

.variable-row {
  display: flex;
  gap: 6px;
  margin-bottom: 6px;
}

.variable-row input {
  font: 0.85rem ui-monospace, monospace;
  padding: 4px 8px;
  background: var(--bg);
  color: var(--text);
  border: 1px solid #333842;
  border-radius: 4px;
}

.variable-row .var-name {
  width: 90px;
}

.variable-row .var-value {
  flex: 1;
}

.variable-row .var-delete {
  font-size: 0.75rem;
  padding: 4px 8px;
}

.var-add {
  font-size: 0.8rem;
  padding: 3px 10px;
  color: var(--muted);
}

.preset {
  font-size: 0.8rem;
  padding: 3px 10px;
  color: var(--muted);
}

button {
  font: inherit;
  padding: 6px 14px;
  background: var(--panel);
  color: var(--text);
  border: 1px solid #333842;
  border-radius: 6px;
  cursor: pointer;
}

button:hover:not(:disabled) {
  border-color: var(--accent);
}

button:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.status {
  margin: 0;
  color: var(--muted);
  font-family: ui-monospace, monospace;
  min-height: 1.2em;
}

.error {
  margin: 0;
  color: var(--error);
  font-family: ui-monospace, monospace;
  min-height: 1.2em;
}

#canvas-wrap {
  background: var(--panel);
  border: 1px solid #333842;
  border-radius: 6px;
  padding: 8px;
}

#treemap-canvas {
  display: block;
  width: 100%;
  height: 60vh;
}