:root {
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  --bg-page: radial-gradient(circle at 20% 20%, #1e293b 0%, #0b1020 50%, #05070f 100%);
  --text-main: #e5e7eb;
  --border-soft: rgba(148, 163, 184, 0.25);
  --sidebar-bg: rgba(8, 12, 24, 0.92);
  --muted-text: #94a3b8;
  --textarea-bg: #0f172a;
  --textarea-text: #f8fafc;
  --input-border: rgba(148, 163, 184, 0.35);
  --chip-bg: #111827;
  --chip-text: #cbd5e1;
  --secondary-bg: #1f2937;
  --secondary-text: #e2e8f0;
  --summary-text: #86efac;
  --error-border: #7f1d1d;
  --error-bg: #450a0a;
  --error-text: #fecaca;
  --scene-border: rgba(148, 163, 184, 0.22);
  --scene-bg: linear-gradient(180deg, #0b1226 0%, #060b17 100%);
}

body[data-theme="light"] {
  --bg-page: radial-gradient(circle at 15% 15%, #ffffff 0%, #eff6ff 45%, #e2e8f0 100%);
  --text-main: #0f172a;
  --border-soft: rgba(100, 116, 139, 0.24);
  --sidebar-bg: rgba(255, 255, 255, 0.92);
  --muted-text: #475569;
  --textarea-bg: #ffffff;
  --textarea-text: #0f172a;
  --input-border: rgba(100, 116, 139, 0.35);
  --chip-bg: #f1f5f9;
  --chip-text: #1e293b;
  --secondary-bg: #e2e8f0;
  --secondary-text: #0f172a;
  --summary-text: #047857;
  --error-border: #dc2626;
  --error-bg: #fff1f2;
  --error-text: #991b1b;
  --scene-border: rgba(100, 116, 139, 0.3);
  --scene-bg: linear-gradient(180deg, #f8fafc 0%, #e2e8f0 100%);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--text-main);
  background: var(--bg-page);
}

.app {
  display: grid;
  grid-template-columns: 360px 1fr;
  min-height: 100vh;
}

.sidebar {
  border-right: 1px solid var(--border-soft);
  background: var(--sidebar-bg);
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  overflow-y: auto;
}

.brand-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.brand h1 {
  margin: 0;
  font-size: 1.3rem;
}

.theme-toggle {
  width: 36px;
  height: 36px;
  border-radius: 999px;
  border: 1px solid var(--input-border);
  background: var(--chip-bg);
  color: var(--chip-text);
  padding: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

.theme-toggle-icon {
  font-size: 1rem;
  line-height: 1;
}

.quick-help {
  border: 1px solid var(--input-border);
  border-radius: 12px;
  padding: 10px;
  background: color-mix(in srgb, var(--chip-bg) 70%, transparent);
}

.help-list {
  margin: 0;
  padding-left: 18px;
  display: grid;
  gap: 6px;
  color: var(--muted-text);
  font-size: 0.82rem;
}

.label,
.section h2 {
  font-size: 0.8rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted-text);
  margin: 0;
}

.textarea {
  min-height: 180px;
  resize: vertical;
  border-radius: 12px;
  border: 1px solid var(--input-border);
  background: var(--textarea-bg);
  color: var(--textarea-text);
  padding: 10px;
  font: 500 13px/1.45 "Fira Code", "JetBrains Mono", Consolas, monospace;
}

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

.examples button {
  border: 1px solid var(--input-border);
  background: var(--chip-bg);
  color: var(--chip-text);
  border-radius: 999px;
  padding: 6px 10px;
  font-size: 0.75rem;
  cursor: pointer;
}

.sliders {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.slider {
  display: grid;
  grid-template-columns: 40px 1fr 56px;
  align-items: center;
  gap: 8px;
  font-size: 0.8rem;
}

.slider input[type="range"] {
  width: 100%;
}

.slider input[type="number"] {
  width: 100%;
  border-radius: 8px;
  border: 1px solid var(--input-border);
  background: var(--textarea-bg);
  color: var(--textarea-text);
  padding: 4px 6px;
}

.actions {
  display: flex;
  gap: 8px;
}

.primary,
.secondary {
  border-radius: 10px;
  border: 1px solid transparent;
  padding: 10px 12px;
  font-weight: 700;
  cursor: pointer;
}

.primary {
  background: #2563eb;
  color: #fff;
}

.secondary {
  background: var(--secondary-bg);
  border-color: var(--input-border);
  color: var(--secondary-text);
}

.summary {
  min-height: 20px;
  color: var(--summary-text);
  font-size: 0.86rem;
}

.error {
  border: 1px solid var(--error-border);
  background: var(--error-bg);
  color: var(--error-text);
  border-radius: 10px;
  padding: 8px 10px;
  font-size: 0.85rem;
}

.canvas-wrap {
  padding: 16px;
}

#scene {
  width: 100%;
  height: calc(100vh - 32px);
  border-radius: 14px;
  border: 1px solid var(--scene-border);
  background: var(--scene-bg);
}

@media (max-width: 900px) {
  .app {
    grid-template-columns: 1fr;
  }
}