/* =========================================================================
   SPHERE LAB — design system
   Split conceptually into: tokens → reset → layout → components → overlay
   ========================================================================= */

/* Self-hosted (SIL OFL 1.1, see fonts/LICENSE-OFL-*.txt) so the page needs no
   third-party font origin. Relative URLs resolve from source and from the build. */
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url('../fonts/inter-latin-400-normal.woff2') format('woff2');
}
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url('../fonts/inter-latin-500-normal.woff2') format('woff2');
}
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  src: url('../fonts/inter-latin-600-normal.woff2') format('woff2');
}
@font-face {
  font-family: 'JetBrains Mono';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url('../fonts/jetbrains-mono-latin-400-normal.woff2') format('woff2');
}
@font-face {
  font-family: 'JetBrains Mono';
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url('../fonts/jetbrains-mono-latin-500-normal.woff2') format('woff2');
}
@font-face {
  font-family: 'JetBrains Mono';
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  src: url('../fonts/jetbrains-mono-latin-600-normal.woff2') format('woff2');
}

:root {
  /* color — dark palette with cool undertones */
  --bg-0: #070910;
  --bg-1: #0d111b;
  --bg-2: #141a27;
  --bg-3: #1c2435;

  --stroke-a: rgba(255, 255, 255, 0.04);
  --stroke-b: rgba(255, 255, 255, 0.08);
  --stroke-c: rgba(255, 255, 255, 0.14);

  --text-0: #edf1f7;
  --text-1: #b4bdd0;
  --text-2: #6d7994;
  --text-3: #3f4863;

  /* semantic colors */
  --accent:       #ffaa33;
  --accent-soft:  rgba(255, 170, 51, 0.18);
  --accent-ghost: rgba(255, 170, 51, 0.08);
  --info:         #6fb9ff;
  --info-soft:    rgba(111, 185, 255, 0.18);
  --ok:           #4bde9a;
  --warn:         #ff5f7a;
  --magenta:      #ff6fa5;
  --violet:       #b285ff;

  /* spacing */
  --s-1: 2px;
  --s-2: 4px;
  --s-3: 6px;
  --s-4: 8px;
  --s-5: 12px;
  --s-6: 16px;
  --s-7: 20px;
  --s-8: 24px;

  /* radius */
  --r-1: 3px;
  --r-2: 5px;
  --r-3: 8px;
  --r-4: 12px;

  /* typography */
  --font-sans: -apple-system, BlinkMacSystemFont, 'Inter', 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, 'SF Mono', Menlo, monospace;

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.45);
  --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.55);

  --ease: cubic-bezier(0.2, 0.8, 0.2, 1);
}

/* ===================== reset ===================== */

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

html, body {
  width: 100%;
  height: 100%;
  background: var(--bg-0);
  color: var(--text-0);
  font-family: var(--font-sans);
  font-size: 13px;
  line-height: 1.4;
  overflow: hidden;
  user-select: none;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

#canvas {
  display: block;
  cursor: crosshair;
  touch-action: none;
  image-rendering: auto;
}

/* scrollbars */
::-webkit-scrollbar       { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--stroke-c); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: rgba(255,255,255,0.22); }

/* ===================== layout ===================== */

/* top bar — title + scene tabs + help, a single compact row */
.topbar {
  position: fixed;
  top: var(--s-5);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: var(--s-5);
  padding: var(--s-2) var(--s-5);
  background: rgba(13, 17, 27, 0.82);
  border: 1px solid var(--stroke-b);
  border-radius: var(--r-3);
  backdrop-filter: blur(20px) saturate(130%);
  -webkit-backdrop-filter: blur(20px) saturate(130%);
  box-shadow: var(--shadow-md);
  max-width: calc(100vw - var(--s-8));
  overflow-x: auto;
  z-index: 3;
}

.topbar .brand {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--text-2);
  padding-right: var(--s-5);
  border-right: 1px solid var(--stroke-b);
  white-space: nowrap;
}

.topbar .brand b { color: var(--accent); font-weight: 600; letter-spacing: 0.28em; }

.scene-tabs {
  display: flex;
  gap: var(--s-1);
}

/* side panels share these base styles */
.panel {
  position: fixed;
  background: rgba(13, 17, 27, 0.85);
  border: 1px solid var(--stroke-b);
  border-radius: var(--r-3);
  backdrop-filter: blur(20px) saturate(130%);
  -webkit-backdrop-filter: blur(20px) saturate(130%);
  box-shadow: var(--shadow-md);
  z-index: 2;
}

.panel-left, .panel-right {
  top: 68px;
  bottom: var(--s-5);
  width: 248px;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transition: transform 0.22s var(--ease), opacity 0.22s var(--ease);
}

.panel-left  { left: var(--s-5); }
.panel-right { right: var(--s-5); }

/* Collapsed = slide the panel off-screen + fade. pointer-events off so it
 * doesn't swallow clicks on canvas while hidden. */
.panel-left.collapsed  { transform: translateX(calc(-100% - var(--s-5) - 2px)); opacity: 0; pointer-events: none; }
.panel-right.collapsed { transform: translateX(calc( 100% + var(--s-5) + 2px)); opacity: 0; pointer-events: none; }

/* Close "×" button in the top corner of each panel. Sits above scroll content. */
.panel-close {
  position: absolute;
  top: 6px;
  width: 22px; height: 22px;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(20, 26, 39, 0.75);
  border: 1px solid var(--stroke-b);
  border-radius: var(--r-1);
  color: var(--text-2);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1;
  cursor: pointer;
  z-index: 2;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}
.panel-left  .panel-close { right: 6px; }
.panel-right .panel-close { right: 6px; }
.panel-close:hover {
  background: var(--bg-3);
  color: var(--text-0);
  border-color: var(--stroke-c);
}

/* Edge handle that appears when a panel is collapsed. Reasonably chunky
 * so it's easy to spot + click at the edge of the viewport. Uses the
 * accent color to stand out, and a soft pulse on first appearance so the
 * eye is drawn to it when a panel collapses. */
.panel-open {
  position: fixed;
  top: 50%;
  width: 30px;
  height: 80px;
  transform: translateY(-50%);
  display: none;
  align-items: center;
  justify-content: center;
  background: rgba(13, 17, 27, 0.92);
  border: 1px solid var(--accent-soft);
  color: var(--accent);
  font-family: var(--font-sans);
  font-size: 20px;
  font-weight: 600;
  line-height: 1;
  cursor: pointer;
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  box-shadow: var(--shadow-md), 0 0 16px var(--accent-ghost);
  z-index: 30;
  padding: 0;
  transition: background 0.15s, color 0.15s, border-color 0.15s, transform 0.15s var(--ease);
}
.panel-open:hover {
  background: var(--bg-3);
  color: var(--text-0);
  border-color: var(--accent);
  box-shadow: var(--shadow-md), 0 0 22px var(--accent-soft);
}
.panel-open-left:hover  { transform: translate(4px, -50%); }
.panel-open-right:hover { transform: translate(-4px, -50%); }
.panel-open.show        { display: flex; animation: panel-open-pulse 1.4s var(--ease) 2; }
.panel-open-left        { left: 0;  border-left: none;  border-radius: 0 var(--r-3) var(--r-3) 0; }
.panel-open-right       { right: 0; border-right: none; border-radius: var(--r-3) 0 0 var(--r-3); }

@keyframes panel-open-pulse {
  0%, 100% { box-shadow: var(--shadow-md), 0 0 16px var(--accent-ghost); }
  50%      { box-shadow: var(--shadow-md), 0 0 28px var(--accent-soft); }
}

.panel-body {
  flex: 1;
  overflow-y: auto;
  padding: var(--s-5);
  display: flex;
  flex-direction: column;
  gap: var(--s-6);
}

/* bottom bar — mode indicator + help button */
.mode-pill {
  position: fixed;
  bottom: var(--s-5);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: var(--s-2);
  padding: var(--s-2) var(--s-5);
  background: rgba(13, 17, 27, 0.82);
  border: 1px solid var(--info-soft);
  border-radius: 999px;
  color: var(--info);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.24em;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: var(--shadow-sm), 0 0 20px var(--info-soft);
  pointer-events: none;
  z-index: 3;
}

.mode-pill .dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--info);
  box-shadow: 0 0 8px var(--info);
  animation: pulse 2s var(--ease) infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50%      { opacity: 0.45; }
}

#help-btn {
  position: fixed;
  bottom: var(--s-5);
  right: var(--s-5);
  z-index: 3;
}

/* Embed mode (?embed=1): an iframe gets the canvas only — every control
   surface is hidden, input still works, and one link opens the full app. */
body.embed .panel,
body.embed .panel-open,
body.embed #help-btn,
body.embed .mode-pill,
body.embed .topbar { display: none; }

#embed-open { display: none; }
body.embed #embed-open {
  display: block;
  position: fixed;
  bottom: var(--s-5);
  right: var(--s-5);
  z-index: 3;
  padding: var(--s-3) var(--s-5);
  background: rgba(13, 17, 27, 0.82);
  border: 1px solid var(--accent-soft);
  border-radius: var(--r-3);
  color: var(--accent);
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 600;
  text-decoration: none;
  box-shadow: var(--shadow-md);
}
body.embed #embed-open:hover,
body.embed #embed-open:focus-visible { border-color: var(--accent); color: var(--text-0); }

/* ===================== components ===================== */

/* section — titled block inside a panel */
.section {
  display: flex;
  flex-direction: column;
  gap: var(--s-3);
}

.section-header {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.22em;
  color: var(--text-2);
  text-transform: uppercase;
  padding: 0 var(--s-2);
}

/* generic button */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--s-2);
  padding: var(--s-3) var(--s-5);
  background: var(--bg-2);
  border: 1px solid var(--stroke-b);
  border-radius: var(--r-2);
  color: var(--text-1);
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: all 0.12s var(--ease);
  white-space: nowrap;
  user-select: none;
}

.btn:hover {
  background: var(--bg-3);
  border-color: var(--stroke-c);
  color: var(--text-0);
}

.btn:active { transform: translateY(0.5px); }

.btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--bg-0);
  box-shadow: 0 0 18px var(--accent-soft);
}

.btn-block { width: 100%; }

.btn-sm { padding: var(--s-2) var(--s-4); font-size: 11px; }

.btn-ghost { background: transparent; border-color: transparent; color: var(--text-2); }
.btn-ghost:hover { background: var(--bg-2); color: var(--text-0); border-color: var(--stroke-b); }

.btn-pill { border-radius: 999px; padding: var(--s-2) var(--s-5); font-size: 11px; }

/* scene tab (inside the top bar) */
.tab {
  padding: var(--s-2) var(--s-4);
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--r-2);
  color: var(--text-2);
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: all 0.12s var(--ease);
  white-space: nowrap;
}
.tab:hover { background: var(--bg-2); color: var(--text-0); }
.tab.active {
  background: var(--accent-ghost);
  color: var(--accent);
  border-color: var(--accent-soft);
}

/* tool button — icon + label, 3×3 grid to fit 9 tools */
.tool-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--s-2);
}

.tool {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--s-2);
  padding: var(--s-4) var(--s-2);
  background: var(--bg-2);
  border: 1px solid var(--stroke-b);
  border-radius: var(--r-2);
  color: var(--text-2);
  cursor: pointer;
  transition: all 0.12s var(--ease);
}

.tool:hover { background: var(--bg-3); color: var(--text-0); border-color: var(--stroke-c); }

.tool.active {
  background: var(--info-soft);
  color: var(--info);
  border-color: var(--info);
  box-shadow: inset 0 0 0 1px rgba(111,185,255,0.15);
}

.tool svg { width: 16px; height: 16px; }
.tool .tool-label {
  font-family: var(--font-mono);
  font-size: 9px;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

/* material palette row */
.mat-list {
  display: flex;
  flex-direction: column;
  gap: var(--s-2);
}

.mat {
  display: flex;
  align-items: center;
  gap: var(--s-4);
  padding: var(--s-3) var(--s-4);
  background: var(--bg-2);
  border: 1px solid var(--stroke-b);
  border-radius: var(--r-2);
  color: var(--text-1);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: all 0.12s var(--ease);
}

.mat:hover { background: var(--bg-3); color: var(--text-0); }

.mat.active {
  background: var(--bg-3);
  border-color: var(--text-1);
  color: var(--text-0);
}

.mat-swatch {
  width: 14px; height: 14px;
  border-radius: 50%;
  flex-shrink: 0;
  position: relative;
}
.mat-swatch::after {
  content: '';
  position: absolute;
  inset: 2px 4px auto auto;
  width: 4px; height: 4px;
  border-radius: 50%;
  background: rgba(255,255,255,0.7);
  mix-blend-mode: screen;
}

.mat-hotkey {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-3);
}

.mat.active .mat-hotkey { color: var(--text-2); }

/* sliders */
.slider-row {
  display: grid;
  grid-template-columns: 64px 1fr 44px;
  align-items: center;
  gap: var(--s-3);
  padding: var(--s-2) var(--s-2);
}

.slider-label {
  font-size: 11px;
  color: var(--text-2);
  letter-spacing: 0.04em;
}

.slider-value {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--accent);
  text-align: right;
  font-variant-numeric: tabular-nums;
}

input[type=range] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 16px;
  background: transparent;
  outline: none;
  cursor: pointer;
}

/* track (both browsers) */
input[type=range]::-webkit-slider-runnable-track {
  height: 3px;
  background: var(--stroke-b);
  border-radius: 2px;
}
input[type=range]::-moz-range-track {
  height: 3px;
  background: var(--stroke-b);
  border-radius: 2px;
}

/* thumb */
input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 12px; height: 12px;
  margin-top: -4.5px;  /* center on 3px track */
  background: var(--accent);
  border: 2px solid var(--bg-0);
  border-radius: 50%;
  box-shadow: 0 0 10px var(--accent-soft);
  cursor: grab;
  transition: transform 0.12s var(--ease);
}
input[type=range]::-moz-range-thumb {
  width: 12px; height: 12px;
  background: var(--accent);
  border: 2px solid var(--bg-0);
  border-radius: 50%;
  box-shadow: 0 0 10px var(--accent-soft);
  cursor: grab;
}

input[type=range]:hover::-webkit-slider-thumb { transform: scale(1.15); }
input[type=range]:active::-webkit-slider-thumb { cursor: grabbing; transform: scale(1.25); }

/* toggle grid — 3 columns of compact toggle pills */
.toggle-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--s-2);
}

.toggle {
  padding: var(--s-2) var(--s-3);
  background: var(--bg-2);
  border: 1px solid var(--stroke-b);
  border-radius: var(--r-1);
  color: var(--text-2);
  font-family: var(--font-mono);
  font-size: 9px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  cursor: pointer;
  transition: all 0.12s var(--ease);
}

.toggle:hover { background: var(--bg-3); color: var(--text-1); }

.toggle.active {
  background: var(--ok);
  color: var(--bg-0);
  border-color: var(--ok);
  box-shadow: 0 0 12px rgba(75, 222, 154, 0.25);
}

/* actions — vertical stack of full-width buttons */
.actions {
  display: flex;
  flex-direction: column;
  gap: var(--s-2);
}

.action-btn {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--s-3) var(--s-4);
  background: var(--bg-2);
  border: 1px solid var(--stroke-b);
  border-radius: var(--r-2);
  color: var(--text-1);
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: all 0.12s var(--ease);
}

.action-btn:hover { background: var(--bg-3); color: var(--text-0); border-color: var(--stroke-c); }

.action-btn.active {
  background: var(--accent-ghost);
  color: var(--accent);
  border-color: var(--accent-soft);
}

.action-btn .kbd {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-3);
  padding: 1px 6px;
  background: var(--bg-0);
  border: 1px solid var(--stroke-b);
  border-radius: var(--r-1);
}

.action-btn.active .kbd { color: var(--accent); border-color: var(--accent-soft); }

/* stats grid + live graphs */
.stat-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 11px;
  color: var(--text-2);
}
.stat-row .v {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-0);
  font-variant-numeric: tabular-nums;
}
.stat-row .v.accent { color: var(--accent); }
.stat-row .v.ok     { color: var(--ok); }
.stat-row .v.info   { color: var(--info); }

.graph-card {
  display: flex;
  flex-direction: column;
  gap: var(--s-2);
  padding: var(--s-3);
  background: rgba(7, 9, 16, 0.65);
  border: 1px solid var(--stroke-a);
  border-radius: var(--r-2);
}
.graph-head {
  display: flex;
  justify-content: space-between;
  font-size: 10px;
  color: var(--text-2);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.graph-head .v {
  font-family: var(--font-mono);
  color: var(--text-0);
  font-variant-numeric: tabular-nums;
  text-transform: none;
  letter-spacing: 0;
}
.graph-card canvas {
  display: block;
  width: 100%;
  height: 36px;
}

/* inline kbd */
.kbd {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-1);
  background: var(--bg-2);
  border: 1px solid var(--stroke-b);
  padding: 1px 6px;
  border-radius: var(--r-1);
  white-space: nowrap;
}

/* ===================== help overlay ===================== */

.overlay {
  position: fixed;
  inset: 0;
  background: rgba(4, 6, 12, 0.78);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 20;
  animation: fade-in 0.18s var(--ease);
}

.overlay.show { display: flex; }

@keyframes fade-in {
  from { opacity: 0; }
  to   { opacity: 1; }
}

.help-box {
  max-width: 780px;
  max-height: 82vh;
  overflow-y: auto;
  padding: var(--s-8);
  background: linear-gradient(180deg, rgba(20, 26, 39, 0.96), rgba(10, 13, 20, 0.96));
  border: 1px solid var(--stroke-c);
  border-radius: var(--r-4);
  box-shadow: var(--shadow-lg), 0 0 60px var(--accent-ghost);
  animation: slide-up 0.25s var(--ease);
}

@keyframes slide-up {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

.help-box h1 {
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 600;
  letter-spacing: 0.32em;
  color: var(--accent);
  margin-bottom: var(--s-1);
}

.help-box .help-sub {
  font-size: 12px;
  color: var(--text-2);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  margin-bottom: var(--s-7);
}

.help-box h4 {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.22em;
  color: var(--ok);
  margin-top: var(--s-7);
  margin-bottom: var(--s-4);
  text-transform: uppercase;
}

.help-grid {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: var(--s-3) var(--s-6);
  font-size: 13px;
  color: var(--text-1);
  line-height: 1.55;
}

.help-prose {
  font-size: 13px;
  line-height: 1.6;
  color: var(--text-1);
}

.help-prose code {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent);
  background: var(--bg-0);
  padding: 1px 4px;
  border-radius: var(--r-1);
}

.help-footer {
  margin-top: var(--s-7);
  text-align: right;
}

/* small utilities */
.divider {
  height: 1px;
  background: var(--stroke-b);
  margin: var(--s-2) 0;
}

/* responsive: hide side panels on narrow screens */
@media (max-width: 900px) {
  .panel-left, .panel-right { display: none; }
}

/* =========================================================================
   THEME PRESETS — swap the accent + info tokens at the :root level so every
   downstream color (buttons, graphs, tooltips, lens-flare sources) follows.
   ========================================================================= */

html[data-theme="cyan"] {
  --accent:       #56d4ff;
  --accent-soft:  rgba(86, 212, 255, 0.18);
  --accent-ghost: rgba(86, 212, 255, 0.08);
  --info:         #b285ff;
  --info-soft:    rgba(178, 133, 255, 0.18);
}

html[data-theme="violet"] {
  --accent:       #c878ff;
  --accent-soft:  rgba(200, 120, 255, 0.18);
  --accent-ghost: rgba(200, 120, 255, 0.08);
  --info:         #ff6fa5;
  --info-soft:    rgba(255, 111, 165, 0.18);
}

html[data-theme="forest"] {
  --accent:       #7ae09e;
  --accent-soft:  rgba(122, 224, 158, 0.18);
  --accent-ghost: rgba(122, 224, 158, 0.08);
  --info:         #ffd07a;
  --info-soft:    rgba(255, 208, 122, 0.18);
}

/* ---- theme swatches in Settings section ---- */
.theme-row {
  display: flex;
  gap: var(--s-3);
  padding: var(--s-2);
}
.theme-dot {
  width: 22px; height: 22px;
  border-radius: 50%;
  cursor: pointer;
  border: 2px solid transparent;
  transition: transform 0.12s var(--ease), border-color 0.12s var(--ease);
}
.theme-dot:hover { transform: scale(1.12); }
.theme-dot.active { border-color: var(--text-0); box-shadow: 0 0 14px currentColor; }
.theme-dot[data-theme="amber"]  { background: #ffaa33; color: #ffaa33; }
.theme-dot[data-theme="cyan"]   { background: #56d4ff; color: #56d4ff; }
.theme-dot[data-theme="violet"] { background: #c878ff; color: #c878ff; }
.theme-dot[data-theme="forest"] { background: #7ae09e; color: #7ae09e; }

/* =========================================================================
   TOOLTIPS — any element with [data-tip] shows a small pill on hover.
   ========================================================================= */

[data-tip] { position: relative; }

[data-tip]::after {
  content: attr(data-tip);
  position: absolute;
  bottom: calc(100% + 6px);
  left: 50%;
  transform: translateX(-50%) translateY(4px);
  padding: 4px 9px;
  background: var(--bg-0);
  color: var(--text-0);
  font-family: var(--font-sans);
  font-size: 11px;
  letter-spacing: 0.03em;
  border: 1px solid var(--stroke-c);
  border-radius: var(--r-2);
  white-space: nowrap;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.12s var(--ease), transform 0.12s var(--ease);
  box-shadow: var(--shadow-sm);
  z-index: 5;
}

[data-tip]:hover::after {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

[data-tip-side="right"]::after {
  bottom: 50%;
  left: calc(100% + 6px);
  transform: translateY(50%) translateX(-4px);
}
[data-tip-side="right"]:hover::after {
  transform: translateY(50%) translateX(0);
}

[data-tip-side="bottom"]::after {
  top: calc(100% + 6px);
  bottom: auto;
  transform: translateX(-50%) translateY(-4px);
}
[data-tip-side="bottom"]:hover::after {
  transform: translateX(-50%) translateY(0);
}

/* =========================================================================
   SCENE TITLE OVERLAY — big center title that fades in when a scene loads.
   ========================================================================= */

.scene-title {
  position: fixed;
  left: 50%;
  top: 40%;
  transform: translate(-50%, -50%);
  text-align: center;
  pointer-events: none;
  z-index: 4;
  opacity: 0;
  transition: opacity 0.35s var(--ease);
}
.scene-title.show {
  /* animation-fill-mode: forwards retains the animation's final frame
     (opacity: 0) so the title actually disappears. Without it the base
     transition would fade the title *back* to opacity: 1 after the
     animation ended, leaving the text permanently on screen. */
  animation: scene-pulse 2s var(--ease) forwards;
}

.scene-title .st-title {
  font-family: var(--font-mono);
  font-size: 44px;
  font-weight: 600;
  letter-spacing: 0.32em;
  color: var(--accent);
  text-shadow: 0 0 30px var(--accent-soft);
  text-transform: uppercase;
}
.scene-title .st-sub {
  margin-top: var(--s-3);
  font-size: 13px;
  color: var(--text-1);
  letter-spacing: 0.12em;
}

@keyframes scene-pulse {
  0%   { opacity: 0;   transform: translate(-50%, -40%); }
  15%  { opacity: 1;   transform: translate(-50%, -50%); }
  70%  { opacity: 1;   transform: translate(-50%, -50%); }
  100% { opacity: 0;   transform: translate(-50%, -58%); }
}

/* =========================================================================
   BALL INSPECTOR — floating card that follows cursor when over a ball.
   ========================================================================= */

.inspector {
  position: fixed;
  pointer-events: none;
  display: none;
  padding: var(--s-4);
  min-width: 180px;
  background: rgba(13, 17, 27, 0.95);
  border: 1px solid var(--stroke-c);
  border-radius: var(--r-3);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: var(--shadow-md);
  z-index: 6;
  font-family: var(--font-sans);
  font-size: 11px;
  transition: opacity 0.1s var(--ease);
}
.inspector.show { display: block; }

.inspector .ins-head {
  display: flex;
  align-items: center;
  gap: var(--s-3);
  padding-bottom: var(--s-3);
  border-bottom: 1px solid var(--stroke-b);
  margin-bottom: var(--s-3);
}
.inspector .ins-swatch {
  width: 14px; height: 14px;
  border-radius: 50%;
}
.inspector .ins-name {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.18em;
  color: var(--text-0);
  text-transform: uppercase;
}
.inspector .ins-id {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-3);
}
.inspector .ins-grid {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 4px 12px;
}
.inspector .ins-grid .k { color: var(--text-2); }
.inspector .ins-grid .v {
  text-align: right;
  color: var(--text-0);
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}
.inspector .ins-heat-bar {
  margin-top: var(--s-3);
  height: 4px;
  background: var(--bg-0);
  border-radius: 2px;
  overflow: hidden;
}
.inspector .ins-heat-bar .fill {
  height: 100%;
  background: linear-gradient(90deg, #ffaa33, #ff4020);
  transition: width 0.12s var(--ease);
}

/* ========================================================================= */
/* narrow action-btn variant — used for the Settings row of small buttons */
.action-row {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: var(--s-2);
}
.action-row .action-btn {
  padding: var(--s-2) var(--s-3);
  font-size: 11px;
  justify-content: center;
}

/* =========================================================================
   SCENE FADE OVERLAY — covers the screen in the background color on scene load
   and fades back in ~350 ms. Hides the first-frame jump when geometry rebuilds.
   ========================================================================= */

.scene-fade {
  position: fixed;
  inset: 0;
  background: var(--bg-0);
  pointer-events: none;
  opacity: 0;
  z-index: 10;
}
.scene-fade.fading {
  animation: scene-fade 0.35s ease;
}
@keyframes scene-fade {
  0%   { opacity: 1; }
  100% { opacity: 0; }
}