*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg: #0d0d1a;
  --surface: #13132a;
  --surface2: #0f0f22;
  --accent: #e8793a;
  --text: #e2e2f0;
  --text-muted: #6b6b8a;
  --border: #1e1e38;
  --radius: 8px;
}

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  height: 100dvh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

#app {
  display: flex;
  flex-direction: column;
  height: 100%;
}

/* ── Header ────────────────────────────────────── */

header {
  padding: 14px 24px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: baseline;
  gap: 14px;
  flex-shrink: 0;
  background: var(--surface2);
}

header h1 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: -0.01em;
}

header p {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ── Main layout ────────────────────────────────── */

main {
  display: flex;
  flex: 1;
  overflow: hidden;
}

/* ── Controls sidebar ───────────────────────────── */

#controls {
  width: 260px;
  flex-shrink: 0;
  padding: 20px 18px;
  display: flex;
  flex-direction: column;
  gap: 18px;
  overflow-y: auto;
  border-right: 1px solid var(--border);
  background: var(--surface2);
}

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

.control-group label {
  font-size: 0.72rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 600;
}

.val {
  color: var(--text);
  font-variant-numeric: tabular-nums;
}

/* Shape buttons */

.button-group {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 5px;
}

.button-group button {
  padding: 7px 6px;
  background: var(--surface);
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 0.78rem;
  transition: border-color 0.12s, color 0.12s, background 0.12s;
  white-space: nowrap;
}

.button-group button:hover {
  border-color: var(--accent);
  color: var(--text);
}

.button-group button.active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
  font-weight: 600;
}

/* Range inputs */

input[type="range"] {
  width: 100%;
  height: 4px;
  accent-color: var(--accent);
  cursor: pointer;
}

/* Color buttons */

.color-row {
  display: flex;
  gap: 6px;
}

.color-btn {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  border: 2px solid transparent;
  cursor: pointer;
  transition: transform 0.12s, border-color 0.12s;
  flex-shrink: 0;
}

.color-btn:hover {
  transform: scale(1.15);
}

.color-btn.active {
  border-color: #fff;
  transform: scale(1.15);
}

/* Download button */

#download-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 0.88rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  transition: opacity 0.12s, transform 0.1s;
  margin-top: auto;
}

#download-btn:hover {
  opacity: 0.88;
}

#download-btn:active {
  transform: scale(0.97);
}

.hint {
  font-size: 0.72rem;
  color: var(--text-muted);
  text-align: center;
}

/* ── 3D Preview ─────────────────────────────────── */

#preview {
  flex: 1;
  position: relative;
  overflow: hidden;
}

#canvas {
  width: 100%;
  height: 100%;
  display: block;
}

#hint-orbit {
  position: absolute;
  bottom: 14px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.72rem;
  color: var(--text-muted);
  pointer-events: none;
  opacity: 0.7;
  white-space: nowrap;
}

/* ── Mobile ─────────────────────────────────────── */

@media (max-width: 640px) {
  header p { display: none; }

  main {
    flex-direction: column-reverse;
  }

  #controls {
    width: 100%;
    max-height: 46vh;
    border-right: none;
    border-top: 1px solid var(--border);
    gap: 12px;
    padding: 14px;
  }

  #controls #download-btn {
    margin-top: 0;
  }

  #preview {
    flex: 1;
    min-height: 0;
  }
}