/* ============================================================
   GLOBAL THEME
   ============================================================ */
:root {
  /* Tweaks-driven knobs (defaults; tweaks.js overrides at runtime) */
  --motion-mult: 1;     /* multiplies orbital durations */
  --pulse-mult: 1;      /* multiplies pulse/core animations */
  --density-scale: 1;   /* scales padding, gaps */
  --density-gap: 1;

  --bg: #050507;
  --bg-2: #0a0a10;
  --glass: rgba(20, 22, 30, 0.55);
  --glass-strong: rgba(18, 20, 28, 0.78);
  --stroke: rgba(255, 255, 255, 0.08);
  --stroke-strong: rgba(255, 255, 255, 0.16);
  --teal: #30d5c8;
  --teal-2: #2cb8ad;
  --teal-soft: rgba(48, 213, 200, 0.5);
  --teal-glow: rgba(48, 213, 200, 0.35);
  --violet: #9d7bff;
  --amber: #f5a623;
  --rose: #ff6a8a;
  --text: #f4f5f7;
  --text-dim: rgba(244, 245, 247, 0.65);
  --text-muted: rgba(244, 245, 247, 0.4);
}

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

html, body {
  height: 100%;
  width: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow: hidden;
}

/* Background */
.bg-layer { position: fixed; inset: 0; pointer-events: none; z-index: 0; }
.bg-grid {
  background-image: radial-gradient(rgba(255,255,255,0.06) 1px, transparent 1px);
  background-size: 28px 28px;
  mask-image: radial-gradient(ellipse at center, rgba(0,0,0,0.9) 0%, rgba(0,0,0,0) 75%);
  -webkit-mask-image: radial-gradient(ellipse at center, rgba(0,0,0,0.9) 0%, rgba(0,0,0,0) 75%);
  opacity: 0.55;
}
.bg-glow {
  background:
    radial-gradient(900px 600px at 18% 12%, rgba(48,213,200,0.07), transparent 60%),
    radial-gradient(800px 600px at 82% 88%, rgba(157,123,255,0.06), transparent 60%);
}

/* ============================================================
   HEADER / FOOTER
   ============================================================ */
.scene-tag {
  position: fixed;
  top: 26px; left: 30px;
  font-size: 11px;
  letter-spacing: 0.32em;
  text-transform: uppercase;
  color: var(--text-muted);
  z-index: 5;
  font-weight: 500;
}
.scene-tag .dot {
  display: inline-block;
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--teal);
  box-shadow: 0 0 10px var(--teal-glow);
  margin-right: 10px;
  vertical-align: middle;
  animation: pulse calc(2.4s * var(--pulse-mult)) ease-in-out infinite;
}
.scene-meta {
  position: fixed;
  top: 26px; right: 30px;
  font-size: 10.5px;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--text-muted);
  z-index: 5;
  text-align: right;
  line-height: 1.7;
}
.scene-meta b { color: var(--text-dim); font-weight: 500; }
.scene-foot {
  position: fixed;
  bottom: 22px; left: 0; right: 0;
  text-align: center;
  font-size: 10.5px;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--text-muted);
  z-index: 5;
}
@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50%      { opacity: 0.4; transform: scale(0.8); }
}

/* ============================================================
   ATOM SCENE
   ============================================================ */
.atom-stage {
  position: relative;
  width: 100%;
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1;
}

.atom {
  position: relative;
  width: 580px; height: 580px;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Nucleus */
.nucleus {
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  width: 200px; height: 200px;
  border-radius: 50%;
  background:
    radial-gradient(circle at 35% 30%, rgba(255,255,255,0.18), rgba(255,255,255,0.04) 45%, rgba(48,213,200,0.10) 70%, transparent 90%),
    radial-gradient(circle at 50% 50%, rgba(48,213,200,0.18), rgba(20,22,30,0.85) 70%);
  border: 1px solid rgba(255,255,255,0.10);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  box-shadow:
    0 0 0 1px rgba(255,255,255,0.04) inset,
    0 0 80px rgba(48,213,200,0.18),
    0 20px 60px rgba(0,0,0,0.55);
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  z-index: 4;
  user-select: none;
}
.nucleus .core {
  position: absolute;
  width: 70%; height: 70%;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(48,213,200,0.18), transparent 70%);
  filter: blur(8px);
  animation: corepulse calc(5s * var(--pulse-mult)) ease-in-out infinite;
}
.atom.frozen .core { animation-play-state: paused; }
@keyframes corepulse {
  0%, 100% { transform: scale(0.95); opacity: 0.7; }
  50%      { transform: scale(1.05); opacity: 1; }
}
.nucleus h1 {
  position: relative;
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  line-height: 1.55;
  color: rgba(255,255,255,0.92);
  padding: 0 24px;
  z-index: 1;
}
.nucleus h1 .lab {
  display: block;
  margin-top: 6px;
  font-size: 10.5px;
  letter-spacing: 0.42em;
  color: var(--teal);
  font-weight: 600;
}

/* Orbits — visual rings (static) */
.orbit {
  position: absolute;
  top: 50%; left: 50%;
  border: 1px dashed rgba(255,255,255,0.07);
  border-radius: 50%;
  transform: translate(-50%, -50%);
  pointer-events: none;
}
.orbit-1 { width: 310px; height: 310px; }
.orbit-2 { width: 410px; height: 410px; }
.orbit-3 { width: 510px; height: 510px; }

/* Ring (electron carrier) — JS-driven rotation via CSS variable for perf
   We use animation-play-state to pause; on hover we ALSO pause (no slow-down,
   so there's no jitter from animation-duration recalc). */
.ring {
  position: absolute;
  top: 50%; left: 50%;
  transform-origin: center center;
  border-radius: 50%;
  pointer-events: none;
  /* will-change forces GPU layer — eliminates jitter */
  will-change: transform;
  transform: translate(-50%, -50%) rotate(0deg);
  animation: spin var(--dur, 16s) linear infinite;
}
.ring-1 { width: 310px; height: 310px; --dur: calc(18s * var(--motion-mult)); }
.ring-2 { width: 410px; height: 410px; --dur: calc(28s * var(--motion-mult)); animation-direction: reverse; }
.ring-3 { width: 510px; height: 510px; --dur: calc(40s * var(--motion-mult)); }

@keyframes spin {
  from { transform: translate(-50%, -50%) rotate(0deg); }
  to   { transform: translate(-50%, -50%) rotate(360deg); }
}

/* ALL rings freeze when atom is frozen (hover or modal open) */
.atom.frozen .ring { animation-play-state: paused; }
.atom.dimmed { filter: blur(8px) brightness(0.4); transition: filter 0.5s; }
.atom { transition: filter 0.5s; }

/* Electron carrier at top of ring */
.electron-wrap {
  position: absolute;
  top: 0; left: 50%;
  transform: translate(-50%, -50%);
  pointer-events: auto;
  cursor: pointer;
  /* hit area expansion */
  width: 90px; height: 90px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 0;
}
.electron-wrap .counter {
  display: flex;
  flex-direction: column;
  align-items: center;
  /* counter-rotate so label stays upright */
  animation: spin-rev var(--dur, 16s) linear infinite;
  will-change: transform;
}
.ring-1 .electron-wrap .counter { animation-duration: calc(18s * var(--motion-mult)); }
.ring-2 .electron-wrap .counter { animation-duration: calc(28s * var(--motion-mult)); animation-direction: reverse; }
.ring-3 .electron-wrap .counter { animation-duration: calc(40s * var(--motion-mult)); }

@keyframes spin-rev {
  from { transform: rotate(0deg); }
  to   { transform: rotate(-360deg); }
}
.atom.frozen .electron-wrap .counter { animation-play-state: paused; }

.electron {
  width: 24px; height: 24px;
  border-radius: 50%;
  background: radial-gradient(circle at 35% 30%, #ffffff, var(--teal) 60%, rgba(48,213,200,0.4) 100%);
  box-shadow:
    0 0 18px var(--teal-glow),
    0 0 40px rgba(48,213,200,0.18),
    inset 0 0 6px rgba(255,255,255,0.6);
  transition: transform 0.35s ease, box-shadow 0.35s ease;
}
.electron-label {
  margin-top: 12px;
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.85);
  white-space: nowrap;
  padding: 6px 14px;
  border-radius: 100px;
  background: rgba(15, 16, 22, 0.5);
  border: 1px solid var(--stroke);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  transition: color 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}

.electron-wrap:hover .electron {
  transform: scale(1.5);
  box-shadow:
    0 0 30px var(--teal),
    0 0 60px var(--teal-glow),
    inset 0 0 10px rgba(255,255,255,0.9);
}
.electron-wrap:hover .electron-label {
  color: var(--teal);
  border-color: var(--teal-soft);
  box-shadow: 0 0 20px var(--teal-glow);
}

/* ============================================================
   OVERLAYS
   ============================================================ */
.overlay {
  position: fixed;
  inset: 0;
  background: rgba(5, 5, 8, 0.55);
  backdrop-filter: blur(28px) saturate(140%);
  -webkit-backdrop-filter: blur(28px) saturate(140%);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 28px 24px;
  z-index: 10;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.4s ease;
}
.overlay.open { opacity: 1; pointer-events: auto; }

.card {
  position: relative;
  width: 100%;
  max-width: 880px;
  max-height: 94vh;
  background: linear-gradient(180deg, rgba(22,24,32,0.88), rgba(12,13,18,0.88));
  border: 1px solid var(--stroke-strong);
  border-radius: 22px;
  box-shadow:
    0 30px 80px rgba(0,0,0,0.6),
    0 0 0 1px rgba(255,255,255,0.04) inset,
    0 0 60px rgba(48,213,200,0.05);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transform: translateY(20px) scale(0.97);
  transition: transform 0.45s cubic-bezier(0.2, 0.9, 0.3, 1.2);
}
.overlay.open .card { transform: translateY(0) scale(1); }

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 28px 16px;
  border-bottom: 1px solid var(--stroke);
  flex: 0 0 auto;
}
.card-header .h-left { display: flex; align-items: center; gap: 14px; }
.card-header .icon-orb {
  width: 30px; height: 30px;
  border-radius: 50%;
  background: radial-gradient(circle at 35% 30%, #fff, var(--teal) 60%, transparent 100%);
  box-shadow: 0 0 14px var(--teal-glow);
}
.card-header h2 {
  font-size: 19px;
  font-weight: 500;
  letter-spacing: 0.04em;
}
.card-header .eyebrow {
  font-size: 10px;
  letter-spacing: 0.32em;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 500;
  margin-bottom: 3px;
}

.close-btn {
  width: 36px; height: 36px;
  border-radius: 50%;
  border: 1px solid var(--stroke);
  background: rgba(255,255,255,0.04);
  color: var(--text);
  font-size: 16px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
}
.close-btn:hover {
  background: rgba(255,255,255,0.10);
  border-color: var(--teal-soft);
  color: var(--teal);
  transform: rotate(90deg);
}

.card-body {
  padding: calc(22px * var(--density-scale)) calc(28px * var(--density-scale)) calc(28px * var(--density-scale));
  overflow-y: auto;
  flex: 1 1 auto;
  scrollbar-width: thin;
  scrollbar-color: rgba(255,255,255,0.15) transparent;
}
.card-body::-webkit-scrollbar { width: 8px; }
.card-body::-webkit-scrollbar-thumb {
  background: rgba(255,255,255,0.12);
  border-radius: 4px;
}

/* Tabs */
.tabs {
  display: flex;
  gap: 4px;
  padding: 4px;
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--stroke);
  border-radius: 12px;
  margin-bottom: 20px;
}
.tab {
  flex: 1;
  padding: 9px 12px;
  font-size: 11.5px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  font-weight: 500;
  text-align: center;
  border: none;
  background: transparent;
  color: var(--text-dim);
  border-radius: 9px;
  cursor: pointer;
  transition: all 0.2s ease;
  font-family: inherit;
}
.tab.active {
  background: rgba(48,213,200,0.10);
  color: var(--teal);
  box-shadow: 0 0 0 1px var(--teal-soft) inset;
}
.tab:hover:not(.active) { color: var(--text); }

.tab-pane { display: none; }
.tab-pane.active { display: block; animation: fadein 0.3s ease; }
@keyframes fadein {
  from { opacity: 0; transform: translateY(4px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* Markdown */
.md h1, .md h2, .md h3, .md h4 {
  font-weight: 500;
  letter-spacing: 0.01em;
  margin: 18px 0 10px;
}
.md h1 { font-size: 22px; color: #fff; border-bottom: 1px solid var(--stroke); padding-bottom: 10px; }
.md h2 { font-size: 17px; color: #fff; }
.md h3 { font-size: 13.5px; color: var(--teal); letter-spacing: 0.12em; text-transform: uppercase; }
.md h4 { font-size: 12.5px; color: var(--violet); letter-spacing: 0.08em; }
.md p, .md li {
  font-size: 13.5px;
  line-height: 1.65;
  color: var(--text-dim);
  margin: 8px 0;
}
.md strong { color: #fff; font-weight: 600; }
.md em { color: var(--text); }
.md ul, .md ol { padding-left: 22px; }
.md code {
  font-family: 'SF Mono', Menlo, Consolas, monospace;
  font-size: 12px;
  background: rgba(48,213,200,0.08);
  color: var(--teal);
  padding: 1.5px 6px;
  border-radius: 4px;
}
.md pre {
  background: rgba(0,0,0,0.4);
  border: 1px solid var(--stroke);
  border-radius: 10px;
  padding: 14px 16px;
  overflow-x: auto;
  margin: 10px 0;
}
.md pre code {
  background: transparent;
  color: var(--text);
  padding: 0;
  font-size: 12px;
  line-height: 1.55;
}
.md blockquote {
  border-left: 2px solid var(--teal);
  padding: 8px 14px;
  margin: 14px 0;
  color: var(--text-dim);
  font-style: italic;
  background: rgba(48,213,200,0.04);
  border-radius: 0 8px 8px 0;
}
.md hr { border: none; border-top: 1px solid var(--stroke); margin: 18px 0; }
.md table { width: 100%; border-collapse: collapse; margin: 12px 0; font-size: 12.5px; }
.md th, .md td { text-align: left; padding: 7px 10px; border-bottom: 1px solid var(--stroke); }
.md th { color: var(--teal); font-weight: 500; letter-spacing: 0.04em; }
.md td { color: var(--text-dim); }
.md a { color: var(--teal); text-decoration: none; border-bottom: 1px dashed var(--teal-soft); }

/* Common widgets */
.panel {
  background: rgba(255,255,255,0.025);
  border: 1px solid var(--stroke);
  border-radius: 14px;
  padding: calc(18px * var(--density-scale));
  margin-bottom: calc(14px * var(--density-gap));
}
.panel-title {
  font-size: 10.5px;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.panel-title .badge {
  font-size: 9px;
  padding: 2px 8px;
  border-radius: 100px;
  background: rgba(48,213,200,0.10);
  color: var(--teal);
  letter-spacing: 0.14em;
  border: 1px solid var(--teal-soft);
}

.row { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.grid-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 12px; }
@media (max-width: 720px) {
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
}

.input-group {
  display: flex;
  align-items: center;
  background: rgba(0,0,0,0.35);
  border: 1px solid var(--stroke);
  border-radius: 10px;
  overflow: hidden;
}
.input-group label {
  padding: 0 12px;
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 500;
}
.input-group .stepper { display: flex; align-items: center; }
.input-group button {
  width: 32px; height: 36px;
  background: transparent;
  border: none;
  color: var(--text-dim);
  font-size: 16px;
  cursor: pointer;
  transition: color 0.2s, background 0.2s;
  font-family: inherit;
}
.input-group button:hover { color: var(--teal); background: rgba(48,213,200,0.08); }
.input-group .val {
  min-width: 38px;
  text-align: center;
  font-size: 16px;
  font-weight: 500;
  color: #fff;
  font-variant-numeric: tabular-nums;
  border-left: 1px solid var(--stroke);
  border-right: 1px solid var(--stroke);
  padding: 8px 4px;
  background: rgba(255,255,255,0.02);
}

.btn {
  background: linear-gradient(180deg, rgba(48,213,200,0.16), rgba(48,213,200,0.08));
  border: 1px solid var(--teal-soft);
  color: var(--teal);
  padding: 10px 18px;
  font-size: 11.5px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  font-weight: 600;
  border-radius: 10px;
  cursor: pointer;
  font-family: inherit;
  transition: all 0.2s ease;
}
.btn:hover:not(:disabled) {
  background: linear-gradient(180deg, rgba(48,213,200,0.28), rgba(48,213,200,0.14));
  box-shadow: 0 0 24px rgba(48,213,200,0.25);
  color: #fff;
}
.btn:disabled { opacity: 0.35; cursor: not-allowed; }
.btn.ghost {
  background: transparent;
  border-color: var(--stroke-strong);
  color: var(--text-dim);
}
.btn.ghost:hover:not(:disabled) {
  background: rgba(255,255,255,0.05);
  color: #fff;
  box-shadow: none;
}
.btn.sm { padding: 7px 12px; font-size: 10.5px; }
.btn.amber {
  background: linear-gradient(180deg, rgba(245,166,35,0.16), rgba(245,166,35,0.08));
  border-color: rgba(245,166,35,0.5);
  color: var(--amber);
}
.btn.amber:hover:not(:disabled) {
  background: linear-gradient(180deg, rgba(245,166,35,0.28), rgba(245,166,35,0.14));
  box-shadow: 0 0 24px rgba(245,166,35,0.25);
  color: #fff;
}

.result-display {
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--text-dim);
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--stroke);
}
.result-display .v {
  display: inline-block;
  font-family: 'SF Mono', Menlo, Consolas, monospace;
  color: var(--teal);
  font-size: 17px;
  font-weight: 600;
  margin-left: 8px;
  text-shadow: 0 0 18px var(--teal-glow);
  word-break: break-all;
}

/* Stat row */
.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 10px;
}
.stat {
  background: rgba(255,255,255,0.02);
  border: 1px solid var(--stroke);
  border-radius: 10px;
  padding: 10px 12px;
}
.stat .lbl {
  font-size: 9.5px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 4px;
}
.stat .val {
  font-family: 'SF Mono', Menlo, Consolas, monospace;
  font-size: 14px;
  color: var(--teal);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}
.stat.amber .val { color: var(--amber); }
.stat.violet .val { color: var(--violet); }

/* SVG charts: container */
.chart {
  background: rgba(0,0,0,0.35);
  border: 1px solid var(--stroke);
  border-radius: 10px;
  padding: 12px;
  margin-top: 10px;
}
.chart svg { width: 100%; display: block; }
.chart .axis text { font-family: 'SF Mono', Menlo, Consolas, monospace; font-size: 9.5px; fill: var(--text-muted); }
.chart .axis line, .chart .axis path { stroke: rgba(255,255,255,0.08); }
.chart .gridline { stroke: rgba(255,255,255,0.04); stroke-dasharray: 2 3; }
.chart .label-x, .chart .label-y { font-size: 10px; fill: var(--text-dim); letter-spacing: 0.06em; text-transform: uppercase; font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; }
.chart .legend { font-size: 10px; fill: var(--text-dim); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; }

/* ============================================================
   STIRLING TABLES
   ============================================================ */
.stirling-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 2px;
  font-size: 12px;
  font-family: 'SF Mono', Menlo, Consolas, monospace;
}
.stirling-table th, .stirling-table td {
  padding: 6px 4px;
  text-align: center;
  background: rgba(255,255,255,0.025);
  border-radius: 4px;
  color: var(--text-dim);
  font-weight: 400;
  min-width: 38px;
  font-variant-numeric: tabular-nums;
}
.stirling-table th {
  background: rgba(48,213,200,0.10);
  color: var(--teal);
  font-size: 11px;
  letter-spacing: 0.08em;
}
.stirling-table td.zero { color: var(--text-muted); opacity: 0.4; }
.stirling-table td.highlight {
  background: rgba(48,213,200,0.22);
  color: #fff;
  box-shadow: 0 0 0 1px var(--teal-soft) inset, 0 0 16px var(--teal-glow);
}
.scroll-x { overflow-x: auto; padding-bottom: 6px; }

.partitions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}
.partition {
  display: flex;
  gap: 4px;
  padding: 7px 10px;
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--stroke);
  border-radius: 8px;
}
.part-block {
  display: flex;
  gap: 3px;
  padding: 3px 6px;
  background: rgba(48,213,200,0.10);
  border-radius: 5px;
}
.dot-el {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--teal);
  box-shadow: 0 0 6px var(--teal-glow);
}

/* ============================================================
   ACKERMANN
   ============================================================ */
.ack-heatmap {
  display: grid;
  grid-template-columns: 36px repeat(var(--cols, 6), 1fr);
  gap: 2px;
  font-size: 11px;
  font-family: 'SF Mono', Menlo, Consolas, monospace;
}
.ack-heatmap .hcell {
  padding: 8px 4px;
  text-align: center;
  border-radius: 4px;
  font-variant-numeric: tabular-nums;
  position: relative;
  overflow: hidden;
}
.ack-heatmap .hcell.head {
  background: transparent;
  color: var(--teal);
  font-size: 10.5px;
  letter-spacing: 0.06em;
}
.ack-heatmap .hcell.row-head {
  background: rgba(48,213,200,0.06);
  color: var(--teal);
  font-weight: 600;
}
.ack-heatmap .hcell.sel {
  outline: 2px solid var(--teal);
  outline-offset: -2px;
  z-index: 2;
  box-shadow: 0 0 18px var(--teal-glow);
}
.ack-heatmap .hcell.huge { color: var(--rose); }

.tree-container {
  max-height: 320px;
  overflow: auto;
  padding: 12px;
  background: rgba(0,0,0,0.3);
  border: 1px solid var(--stroke);
  border-radius: 10px;
  font-family: 'SF Mono', Menlo, Consolas, monospace;
  font-size: 12px;
}
.tree-line {
  white-space: pre-wrap;
  word-break: break-all;
  padding: 1px 0;
  color: var(--text-dim);
  animation: fadein 0.2s ease;
}
.tree-line.computed { color: var(--teal); text-shadow: 0 0 10px var(--teal-glow); }
.tree-line.current { color: #fff; background: rgba(48,213,200,0.10); border-radius: 3px; }

.warn-banner {
  font-size: 11px;
  color: #f5a623;
  background: rgba(245,166,35,0.08);
  border: 1px solid rgba(245,166,35,0.25);
  padding: 8px 12px;
  border-radius: 8px;
  margin-bottom: 14px;
  letter-spacing: 0.04em;
}

.formula-card {
  background: rgba(157,123,255,0.06);
  border: 1px solid rgba(157,123,255,0.25);
  border-radius: 10px;
  padding: 12px 14px;
  font-family: 'SF Mono', Menlo, Consolas, monospace;
  font-size: 12px;
  color: var(--violet);
  letter-spacing: 0.02em;
}
.formula-card .ftitle {
  font-size: 9.5px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 6px;
  font-family: -apple-system, BlinkMacSystemFont, sans-serif;
}

/* ============================================================
   NIM
   ============================================================ */
.nim-board {
  display: flex;
  justify-content: center;
  gap: 24px;
  padding: 18px 8px;
  min-height: 180px;
  align-items: flex-end;
  flex-wrap: wrap;
}
.pile {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  min-width: 44px;
  padding: 10px 8px 8px;
  border-radius: 12px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.25s ease;
}
.pile:hover { background: rgba(255,255,255,0.03); }
.pile.selected {
  background: rgba(48,213,200,0.08);
  border-color: var(--teal-soft);
  box-shadow: 0 0 24px rgba(48,213,200,0.18);
}
.pile.disabled { cursor: default; opacity: 0.4; }
.pile-stones {
  display: flex;
  flex-direction: column-reverse;
  gap: 5px;
}
.stone {
  width: 22px; height: 22px;
  border-radius: 50%;
  background: radial-gradient(circle at 35% 30%, #fff, var(--teal) 60%, rgba(48,213,200,0.5));
  box-shadow: 0 0 10px var(--teal-glow), inset 0 0 4px rgba(255,255,255,0.6);
  transition: opacity 0.4s ease, transform 0.4s ease;
}
.stone.removing { opacity: 0; transform: translateY(-12px) scale(0.4); }
.pile-label {
  font-size: 10px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-muted);
}
.pile-count {
  font-family: 'SF Mono', Menlo, Consolas, monospace;
  font-size: 13px;
  color: var(--teal);
  font-weight: 600;
}

.turn-indicator {
  text-align: center;
  font-size: 12px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--text-dim);
  padding: 12px;
  border-radius: 10px;
  background: rgba(255,255,255,0.025);
  border: 1px solid var(--stroke);
  margin-bottom: 14px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}
.turn-indicator.you { color: var(--teal); border-color: var(--teal-soft); }
.turn-indicator.ai { color: var(--amber); border-color: rgba(245,166,35,0.3); background: rgba(245,166,35,0.05); }
.turn-indicator .nim-sum {
  font-family: 'SF Mono', Menlo, Consolas, monospace;
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  text-transform: none;
}
.turn-indicator .nim-sum b { color: var(--violet); }

.nim-controls {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  padding: 12px;
  background: rgba(0,0,0,0.25);
  border: 1px solid var(--stroke);
  border-radius: 12px;
  margin-top: 14px;
}
.nim-log {
  max-height: 110px;
  overflow-y: auto;
  font-family: 'SF Mono', Menlo, Consolas, monospace;
  font-size: 11px;
  background: rgba(0,0,0,0.3);
  border: 1px solid var(--stroke);
  border-radius: 8px;
  padding: 8px 12px;
  margin-top: 12px;
  color: var(--text-dim);
}
.nim-log .entry { padding: 1.5px 0; }
.nim-log .you { color: var(--teal); }
.nim-log .ai { color: var(--amber); }

.game-end {
  text-align: center;
  padding: 22px;
  border-radius: 14px;
  background: linear-gradient(180deg, rgba(48,213,200,0.10), rgba(48,213,200,0.02));
  border: 1px solid var(--teal-soft);
  margin-top: 16px;
}
.game-end.lose {
  background: linear-gradient(180deg, rgba(245,90,90,0.08), rgba(245,90,90,0.02));
  border-color: rgba(245,90,90,0.4);
}
.game-end h3 {
  font-size: 24px;
  font-weight: 500;
  margin-bottom: 6px;
  letter-spacing: 0.04em;
}
.game-end p { font-size: 12px; color: var(--text-dim); margin-bottom: 14px; letter-spacing: 0.08em; }

/* Variant selector */
.variant-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 8px;
  margin-bottom: 14px;
}
@media (max-width: 720px) { .variant-grid { grid-template-columns: 1fr; } }
.variant-card {
  padding: 12px;
  background: rgba(255,255,255,0.025);
  border: 1px solid var(--stroke);
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.2s ease;
}
.variant-card:hover { background: rgba(255,255,255,0.05); border-color: var(--stroke-strong); }
.variant-card.active {
  background: rgba(48,213,200,0.08);
  border-color: var(--teal-soft);
  box-shadow: 0 0 18px rgba(48,213,200,0.15);
}
.variant-card .vname {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  margin-bottom: 4px;
  color: #fff;
}
.variant-card.active .vname { color: var(--teal); }
.variant-card .vdesc {
  font-size: 11px;
  color: var(--text-dim);
  line-height: 1.5;
}

.diff-segment {
  display: inline-flex;
  background: rgba(0,0,0,0.35);
  border: 1px solid var(--stroke);
  border-radius: 10px;
  padding: 3px;
}
.diff-segment button {
  padding: 6px 12px;
  font-size: 10.5px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  font-weight: 600;
  border: none;
  background: transparent;
  color: var(--text-dim);
  border-radius: 8px;
  cursor: pointer;
  font-family: inherit;
}
.diff-segment button.active { background: rgba(48,213,200,0.12); color: var(--teal); }
.diff-segment button:hover:not(.active) { color: #fff; }

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 700px) {
  .atom { width: 360px; height: 360px; }
  .nucleus { width: 130px; height: 130px; }
  .nucleus h1 { font-size: 10.5px; padding: 0 14px; }
  .nucleus h1 .lab { font-size: 9px; }
  .orbit-1, .ring-1 { width: 200px; height: 200px; }
  .orbit-2, .ring-2 { width: 270px; height: 270px; }
  .orbit-3, .ring-3 { width: 340px; height: 340px; }
  .electron-label { font-size: 9.5px; padding: 4px 10px; letter-spacing: 0.18em; }
  .scene-tag, .scene-meta { left: 16px; top: 16px; font-size: 9px; }
  .scene-meta { right: 16px; left: auto; }
  .card-header { padding: 16px 18px; }
  .card-body { padding: 18px; }
}

/* ============================================================
   TWEAKS PANEL
   ============================================================ */
#tweaks-panel {
  position: fixed;
  right: 20px;
  bottom: 20px;
  width: 286px;
  background: var(--glass-strong);
  backdrop-filter: blur(24px) saturate(140%);
  -webkit-backdrop-filter: blur(24px) saturate(140%);
  border: 1px solid var(--stroke-strong);
  border-radius: 16px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.5), 0 0 0 1px rgba(255,255,255,0.04) inset;
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, sans-serif;
  z-index: 9999;
  opacity: 0;
  pointer-events: none;
  transform: translateY(8px);
  transition: opacity 0.22s ease, transform 0.22s ease;
}
#tweaks-panel.open {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}
#tweaks-panel .tw-head {
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 14px;
  border-bottom: 1px solid var(--stroke);
  cursor: grab;
  user-select: none;
}
#tweaks-panel .tw-head:active { cursor: grabbing; }
#tweaks-panel .tw-title {
  display: flex; align-items: center; gap: 10px;
  font-size: 10.5px;
  letter-spacing: 0.32em;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 500;
}
#tweaks-panel .tw-dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--teal);
  box-shadow: 0 0 10px var(--teal-glow);
}
#tweaks-panel .tw-close {
  width: 24px; height: 24px;
  border-radius: 6px;
  border: 1px solid var(--stroke);
  background: rgba(255,255,255,0.04);
  color: var(--text-dim);
  cursor: pointer;
  font-size: 12px;
  line-height: 1;
  display: flex; align-items: center; justify-content: center;
  transition: all 0.18s;
}
#tweaks-panel .tw-close:hover {
  border-color: var(--teal-soft);
  color: var(--teal);
}
#tweaks-panel .tw-body { padding: 6px 14px 4px; }
#tweaks-panel .tw-section {
  padding: 12px 0;
  border-bottom: 1px dashed var(--stroke);
}
#tweaks-panel .tw-section:last-child { border-bottom: none; }
#tweaks-panel .tw-label {
  font-size: 11px;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  color: var(--text);
  font-weight: 500;
  margin-bottom: 2px;
}
#tweaks-panel .tw-sub {
  font-size: 10.5px;
  color: var(--text-muted);
  margin-bottom: 10px;
  letter-spacing: 0.04em;
}
#tweaks-panel .tw-radio {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 6px;
}
#tweaks-panel .tw-opt {
  display: flex; flex-direction: column; align-items: center; gap: 6px;
  padding: 9px 6px 8px;
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--stroke);
  border-radius: 9px;
  color: var(--text-dim);
  cursor: pointer;
  transition: all 0.18s;
  font-family: inherit;
}
#tweaks-panel .tw-opt:hover {
  background: rgba(255,255,255,0.06);
  color: var(--text);
}
#tweaks-panel .tw-opt.on {
  background: rgba(48,213,200,0.10);
  border-color: var(--teal-soft);
  color: var(--teal);
  box-shadow: 0 0 16px var(--teal-glow);
}
#tweaks-panel .tw-opt-label {
  font-size: 10.5px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-weight: 500;
}
#tweaks-panel .tw-radio-text .tw-opt { padding: 10px 4px; }
#tweaks-panel .tw-swatch {
  width: 100%;
  height: 26px;
  border-radius: 6px;
  border: 1px solid rgba(255,255,255,0.08);
}
#tweaks-panel .tw-swatch-cryo {
  background:
    radial-gradient(circle at 28% 50%, #30d5c8 0 26%, transparent 28%),
    radial-gradient(circle at 72% 50%, #9d7bff 0 26%, transparent 28%),
    linear-gradient(135deg, #050507, #14161e);
}
#tweaks-panel .tw-swatch-solar {
  background:
    radial-gradient(circle at 28% 50%, #f5a623 0 26%, transparent 28%),
    radial-gradient(circle at 72% 50%, #ff6a8a 0 26%, transparent 28%),
    linear-gradient(135deg, #160c08, #0e0805);
}
#tweaks-panel .tw-swatch-mono {
  background:
    radial-gradient(circle at 28% 50%, #1a1612 0 26%, transparent 28%),
    radial-gradient(circle at 72% 50%, #7a4d2b 0 26%, transparent 28%),
    linear-gradient(135deg, #f4f1ea, #ebe6db);
}
#tweaks-panel .tw-hint {
  margin-top: 10px;
  font-size: 10.5px;
  color: var(--text-muted);
  letter-spacing: 0.04em;
  font-style: italic;
}
#tweaks-panel .tw-foot {
  padding: 8px 14px 10px;
  border-top: 1px solid var(--stroke);
  font-size: 9.5px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--text-muted);
  text-align: center;
}

/* ============================================================
   MOTION · FRANTIC flourish — small visual cue when manic
   ============================================================ */
body[data-motion="frantic"] .nucleus .core {
  filter: brightness(1.25) saturate(1.2);
}
body[data-motion="calm"] .electron {
  filter: brightness(0.92);
}

/* ============================================================
   THEME · PAPER (light) — overrides for elements that hard-code
   white/dark-only values
   ============================================================ */
body.theme-light {
  background: var(--bg);
  color: var(--text);
}
body.theme-light .scene-tag,
body.theme-light .scene-meta,
body.theme-light .scene-foot {
  color: var(--text-muted);
}
body.theme-light .nucleus {
  background: rgba(255, 253, 248, 0.55);
  border-color: var(--stroke-strong);
  box-shadow: 0 0 40px rgba(26,22,18,0.08), inset 0 0 30px rgba(255,255,255,0.4);
}
body.theme-light .nucleus h1 { color: var(--text); }
body.theme-light .nucleus h1 .lab { color: var(--teal); }
body.theme-light .core {
  background: radial-gradient(circle, rgba(26,22,18,0.10), transparent 70%);
}
body.theme-light .orbit {
  border-color: rgba(20,18,14,0.18);
}
body.theme-light .ring { border-color: transparent; }
body.theme-light .electron {
  background: radial-gradient(circle at 35% 30%, #fff, var(--teal) 50%, var(--teal-soft) 100%);
  box-shadow: 0 0 14px var(--teal-glow), inset 0 0 4px rgba(255,255,255,0.6);
}
body.theme-light .electron-label {
  background: rgba(255,253,248,0.78);
  color: var(--text-dim);
  border: 1px solid var(--stroke);
}
body.theme-light .card {
  background: rgba(252,250,244,0.96);
  border-color: var(--stroke-strong);
}
body.theme-light .panel {
  background: rgba(20,18,14,0.025);
  border-color: var(--stroke);
}
body.theme-light .stat,
body.theme-light .formula-card,
body.theme-light .chart {
  background: rgba(20,18,14,0.025);
  border: 1px solid var(--stroke);
}
body.theme-light .stirling-table th { background: rgba(26,22,18,0.08); }
body.theme-light .stirling-table td { background: rgba(20,18,14,0.025); }
body.theme-light .stirling-table td.highlight {
  background: rgba(26,22,18,0.85);
  color: #fff;
}
body.theme-light .tab.active {
  background: rgba(26,22,18,0.10);
}
body.theme-light .md h1,
body.theme-light .md h2,
body.theme-light .md strong { color: var(--text); }
body.theme-light .md pre,
body.theme-light .md code {
  background: rgba(20,18,14,0.06);
}
body.theme-light .md pre { border: 1px solid var(--stroke); }
body.theme-light .md blockquote { background: rgba(26,22,18,0.04); }
body.theme-light .stone {
  background: radial-gradient(circle at 35% 30%, #fff, var(--teal) 50%, var(--teal-soft));
}
body.theme-light .pile { background: rgba(20,18,14,0.025); }
body.theme-light .pile.selected {
  background: rgba(26,22,18,0.06);
}
body.theme-light .turn-indicator { background: rgba(20,18,14,0.04); }
body.theme-light .nim-log { background: rgba(20,18,14,0.05); }
body.theme-light .ack-heatmap .hcell { background: rgba(20,18,14,0.04); }
body.theme-light .tree-line.current { background: rgba(26,22,18,0.10); color: var(--text); }
body.theme-light .close-btn {
  background: rgba(20,18,14,0.04);
  color: var(--text-dim);
}
body.theme-light .chart .axis line,
body.theme-light .chart .axis path { stroke: rgba(20,18,14,0.25); }
body.theme-light .chart .gridline { stroke: rgba(20,18,14,0.10); }

/* Solar theme: a few targeted nudges (most cascades through vars) */
body[data-theme="solar"] .nucleus h1 .lab { color: var(--amber); }
body[data-theme="solar"] .scene-foot { letter-spacing: 0.32em; }