:root {
  --bg: #f2f0f7;
  --panel: #fffdf9;
  --ink: #282531;
  --muted: #6f6a78;
  --good: #168349;
  --bad: #b33d49;
  --shadow: 0 16px 42px rgba(49, 38, 77, .09);
  font-family: Inter, ui-rounded, "Segoe UI", "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  font-synthesis: none;
}

* { box-sizing: border-box; }
html { min-width: 320px; min-height: 100%; scroll-behavior: smooth; }
body {
  min-width: 320px;
  min-height: 100vh;
  margin: 0;
  background:
    radial-gradient(circle at 7% 2%, rgba(119, 86, 199, .13), transparent 27rem),
    radial-gradient(circle at 97% 18%, rgba(35, 84, 216, .08), transparent 25rem),
    linear-gradient(180deg, #f8f6fb 0%, var(--bg) 100%);
}
button, input { font: inherit; }
button { cursor: pointer; }
button:focus-visible,
input:focus-visible,
summary:focus-visible,
[tabindex]:focus-visible {
  outline: 3px solid rgba(119, 86, 199, .38);
  outline-offset: 3px;
}
.hidden { display: none !important; }

.standalone-shell {
  width: min(1180px, calc(100% - 28px));
  margin: 0 auto;
  padding: 22px 0 28px;
}
.panel {
  border: 1px solid rgba(77, 65, 105, .12);
  border-radius: 24px;
  background: var(--panel);
  box-shadow: var(--shadow);
}
.eyebrow {
  display: block;
  margin: 0 0 5px;
  color: #7756c7;
  font-size: .68rem;
  font-weight: 900;
  letter-spacing: .12em;
  line-height: 1.3;
  text-transform: uppercase;
}
.secondary-button,
.danger-button,
.primary-button {
  min-height: 40px;
  padding: 9px 14px;
  border: 1px solid rgba(77, 65, 105, .18);
  border-radius: 12px;
  color: var(--ink);
  background: #fff;
  font-size: .78rem;
  font-weight: 850;
  transition: border-color .15s ease, background .15s ease, transform .15s ease;
}
.secondary-button:hover:not(:disabled),
.danger-button:hover:not(:disabled),
.primary-button:hover:not(:disabled) { transform: translateY(-1px); }
.secondary-button:hover:not(:disabled) {
  border-color: rgba(119, 86, 199, .42);
  background: #faf8ff;
}
.danger-button {
  color: var(--bad);
  border-color: rgba(179, 61, 73, .25);
  background: rgba(179, 61, 73, .04);
}
.danger-button:hover:not(:disabled) { background: rgba(179, 61, 73, .1); }

.app-header {
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 14px;
  padding: 0 6px;
}
.app-brand { display: flex; align-items: center; gap: 12px; }
.app-back-link {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  border: 2px solid var(--ink);
  border-radius: 999px;
  color: var(--ink);
  background: rgba(255,255,255,.56);
  font-size: .72rem;
  font-weight: 950;
  text-decoration: none;
}
.app-brand-symbol {
  width: 48px;
  height: 48px;
  display: grid;
  place-items: center;
  border-radius: 15px;
  color: #fff;
  background: linear-gradient(145deg, #9879df, #6040a9);
  box-shadow: 0 10px 22px rgba(96, 64, 169, .24);
  font: 900 1.7rem/1 Georgia, "Times New Roman", serif;
}
.app-header h1 { margin: 0; font-size: clamp(1.28rem, 3vw, 1.65rem); letter-spacing: -.025em; }
.offline-badge {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 8px 11px;
  border: 1px solid rgba(22, 131, 73, .2);
  border-radius: 999px;
  color: #126d3d;
  background: rgba(22, 131, 73, .07);
  font-size: .72rem;
  font-weight: 850;
  white-space: nowrap;
}
.offline-badge span { color: #1c9b59; font-size: .62rem; }
.app-header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}
.app-language-switcher {
  display: flex;
  gap: 3px;
  padding: 3px;
  border: 1px solid rgba(77, 65, 105, .14);
  border-radius: 12px;
  background: rgba(255,255,255,.72);
}
.app-language-switcher button {
  min-height: 32px;
  padding: 5px 9px;
  border: 0;
  border-radius: 9px;
  color: var(--muted);
  background: transparent;
  font-size: .7rem;
  font-weight: 900;
}
.app-language-switcher button.active {
  color: #fff;
  background: var(--mobius-violet);
}
.app-footer {
  padding: 20px 8px 2px;
  color: var(--muted);
  font-size: .73rem;
  line-height: 1.5;
  text-align: center;
}
noscript {
  display: block;
  margin: 20px;
  padding: 16px;
  border: 1px solid #c56c70;
  border-radius: 14px;
  color: #7b2329;
  background: #fff4f4;
  text-align: center;
}

.mobius-lab-screen {
  --mobius-blue: #2354d8;
  --mobius-copper: #ad6a2e;
  --mobius-green: #159447;
  --mobius-violet: #7756c7;
  --mobius-paper: #fffdf8;
  --mobius-line: #27242c;
  --mobius-soft: color-mix(in srgb, var(--mobius-violet) 9%, var(--panel));
}
.mobius-hero {
  position: relative;
  margin-bottom: 14px;
  padding: 24px;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 20px;
  overflow: hidden;
  border-color: color-mix(in srgb, var(--mobius-violet) 30%, transparent);
  background:
    radial-gradient(circle at 93% 8%, color-mix(in srgb, var(--mobius-violet) 14%, transparent), transparent 30%),
    var(--panel);
}
.mobius-hero-symbol {
  width: 76px;
  height: 76px;
  display: grid;
  place-items: center;
  border-radius: 23px;
  color: #fff;
  background: linear-gradient(145deg, #9879df, #6040a9);
  box-shadow: 0 14px 30px color-mix(in srgb, var(--mobius-violet) 28%, transparent);
  font: 900 2.5rem/1 Georgia, "Times New Roman", serif;
}
.mobius-hero h2 { margin: 0 0 7px; font-size: clamp(1.6rem, 3.6vw, 2.35rem); }
.mobius-hero p:last-child { margin: 0; max-width: 670px; color: var(--muted); line-height: 1.55; }
.mobius-reference-badge,
.mobius-diagram-pill {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 7px 10px;
  border-radius: 999px;
  color: color-mix(in srgb, var(--mobius-violet) 86%, var(--ink));
  background: color-mix(in srgb, var(--mobius-violet) 11%, var(--panel));
  border: 1px solid color-mix(in srgb, var(--mobius-violet) 30%, transparent);
  font-size: .72rem;
  font-weight: 900;
  white-space: nowrap;
}

.mobius-controls {
  margin-bottom: 14px;
  padding: 18px;
  display: grid;
  grid-template-columns: minmax(170px, .72fr) minmax(240px, 1fr) minmax(240px, 1fr);
  gap: 14px;
  border-color: color-mix(in srgb, var(--mobius-violet) 24%, transparent);
}
.mobius-control-group {
  min-width: 0;
  padding: 14px;
  border-radius: 18px;
  background: var(--mobius-soft);
  border: 1px solid color-mix(in srgb, var(--mobius-violet) 18%, transparent);
}
.mobius-control-label,
.mobius-control-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 10px;
  color: var(--ink);
  font-size: .78rem;
  font-weight: 900;
  letter-spacing: .035em;
}
.mobius-control-heading output {
  min-width: 35px;
  padding: 4px 8px;
  border-radius: 999px;
  color: #fff;
  background: var(--mobius-violet);
  text-align: center;
  font-size: .82rem;
}
.mobius-point-count-control input[type="range"] {
  width: 100%;
  accent-color: var(--mobius-violet);
  cursor: pointer;
}
.mobius-range-labels {
  display: flex;
  justify-content: space-between;
  color: var(--muted);
  font-size: .68rem;
  font-weight: 800;
}
.mobius-segmented {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 5px;
  padding: 4px;
  border-radius: 14px;
  background: color-mix(in srgb, var(--mobius-violet) 9%, var(--panel));
  border: 1px solid color-mix(in srgb, var(--mobius-violet) 22%, transparent);
}
.mobius-segmented button {
  min-height: 42px;
  padding: 8px 10px;
  border: 0;
  border-radius: 10px;
  color: var(--muted);
  background: transparent;
  font-size: .78rem;
  font-weight: 850;
  transition: color .16s ease, background .16s ease, box-shadow .16s ease;
}
.mobius-segmented button:hover { color: var(--ink); }
.mobius-segmented button:disabled { cursor: not-allowed; opacity: .42; }
.mobius-segmented button.active {
  color: #fff;
  background: var(--mobius-violet);
  box-shadow: 0 6px 14px color-mix(in srgb, var(--mobius-violet) 28%, transparent);
}
.mobius-control-group small {
  display: block;
  margin-top: 8px;
  color: var(--muted);
  line-height: 1.35;
  font-size: .69rem;
}
.mobius-control-actions {
  grid-column: 1 / -1;
  display: flex;
  justify-content: flex-end;
  gap: 8px;
  flex-wrap: wrap;
}
.mobius-control-actions button { min-height: 40px; padding: 9px 13px; }
.mobius-control-actions button:disabled { opacity: .48; cursor: not-allowed; }
.mobius-example-button {
  margin-right: auto;
  color: color-mix(in srgb, var(--mobius-violet) 88%, var(--ink));
  border-color: color-mix(in srgb, var(--mobius-violet) 34%, transparent);
  background: color-mix(in srgb, var(--mobius-violet) 9%, var(--panel));
}
.mobius-status {
  grid-column: 1 / -1;
  min-height: 48px;
  display: flex;
  align-items: center;
  padding: 12px 14px;
  border-radius: 14px;
  color: color-mix(in srgb, var(--mobius-violet) 84%, var(--ink));
  background: color-mix(in srgb, var(--mobius-violet) 10%, var(--panel));
  border: 1px solid color-mix(in srgb, var(--mobius-violet) 24%, transparent);
  font-size: .82rem;
  font-weight: 800;
  line-height: 1.4;
}
.mobius-status.is-warning {
  color: #925d14;
  background: color-mix(in srgb, #e7a83a 14%, var(--panel));
  border-color: color-mix(in srgb, #d99524 38%, transparent);
}
.mobius-status.is-success {
  color: color-mix(in srgb, var(--good) 82%, var(--ink));
  background: color-mix(in srgb, var(--good) 10%, var(--panel));
  border-color: color-mix(in srgb, var(--good) 30%, transparent);
}

.mobius-diagram-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  align-items: stretch;
}
.mobius-diagram-card {
  min-width: 0;
  padding: 18px;
  overflow: hidden;
  border-color: color-mix(in srgb, var(--mobius-violet) 22%, transparent);
}
.mobius-diagram-heading,
.mobius-register-heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
}
.mobius-diagram-heading h3,
.mobius-register-heading h3 { margin: 0; font-size: 1.18rem; }
.mobius-diagram-heading .eyebrow,
.mobius-register-heading .eyebrow { margin-bottom: 4px; }
.mobius-diagram {
  width: 100%;
  height: auto;
  aspect-ratio: 1;
  display: block;
  margin: 8px auto 4px;
  border-radius: 20px;
  background: radial-gradient(circle at 48% 42%, rgba(255,255,255,.96), rgba(255,253,248,.96) 66%, rgba(244,240,230,.94));
  border: 1px solid color-mix(in srgb, var(--mobius-line) 10%, transparent);
  touch-action: manipulation;
}
.mobius-diagram-help {
  min-height: 36px;
  display: flex;
  align-items: flex-start;
  gap: 8px;
  margin: 6px 2px 0;
  color: var(--muted);
  font-size: .73rem;
  line-height: 1.4;
}
.mobius-green-dot,
.outer-sheet-dot,
.inner-sheet-dot {
  width: 10px;
  height: 10px;
  flex: 0 0 10px;
  display: inline-block;
  border-radius: 50%;
  background: var(--mobius-green);
  box-shadow: 0 0 0 2px color-mix(in srgb, var(--mobius-green) 18%, transparent);
}
.outer-sheet-dot { background: var(--mobius-green); }
.inner-sheet-dot { background: #25a88e; }
.mobius-cover-legend {
  min-height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
  color: var(--muted);
  font-size: .7rem;
  font-weight: 750;
}
.mobius-cover-legend span { display: inline-flex; align-items: center; gap: 5px; }
.deck-symbol {
  min-width: 20px;
  height: 20px;
  display: inline-grid;
  place-items: center;
  border-radius: 50%;
  color: var(--mobius-violet);
  background: color-mix(in srgb, var(--mobius-violet) 12%, var(--panel));
  font: 800 .78rem/1 Georgia, serif;
}

.mobius-surface-disk,
.mobius-cover-annulus {
  fill: #fffefa;
  stroke: var(--mobius-line);
  stroke-width: 3;
}
.mobius-cover-hole {
  fill: #d9d7d4;
  stroke: var(--mobius-line);
  stroke-width: 3;
}
.mobius-crosscap-disc {
  fill: #fff;
  stroke: var(--mobius-line);
  stroke-width: 2.8;
}
.mobius-crosscap-line { stroke: var(--mobius-line); stroke-width: 2.3; stroke-linecap: round; }
.mobius-arc-path {
  fill: none;
  stroke-width: 5.5;
  stroke-linecap: round;
  stroke-linejoin: round;
  vector-effect: non-scaling-stroke;
  transition: opacity .16s ease, filter .16s ease, stroke-width .16s ease;
}
.mobius-arc-group { cursor: pointer; }
.mobius-arc-group.is-muted .mobius-arc-path { opacity: .3; }
.mobius-arc-group.is-active .mobius-arc-path {
  stroke-width: 7;
  filter: drop-shadow(0 0 5px color-mix(in srgb, currentColor 48%, transparent));
}
.mobius-crosscap-seam {
  fill: none;
  stroke-width: 2;
  stroke-dasharray: 4 4;
  opacity: .78;
}
.mobius-mark {
  fill: var(--mobius-green);
  stroke: #fff;
  stroke-width: 3;
  filter: drop-shadow(0 2px 3px rgba(0,0,0,.24));
  transition: r .14s ease, filter .14s ease;
}
.mobius-inner-mark { fill: #25a88e; }
.mobius-mark-group { cursor: pointer; outline: none; }
.mobius-mark-group:hover .mobius-mark,
.mobius-mark-group:focus-visible .mobius-mark,
.mobius-mark-group.is-selected .mobius-mark {
  r: 10px;
  filter: drop-shadow(0 0 7px rgba(21,148,71,.75));
}
.mobius-mark-halo { fill: color-mix(in srgb, var(--mobius-green) 22%, transparent); }
.mobius-mark-hit { fill: transparent; }
.mobius-mark-label {
  fill: var(--mobius-line);
  font: 800 14px/1 Inter, ui-rounded, sans-serif;
  text-anchor: middle;
  dominant-baseline: middle;
  pointer-events: none;
}
.mobius-sheet-label {
  fill: #6b6571;
  font: 800 12px/1 Inter, ui-rounded, sans-serif;
  text-anchor: middle;
  dominant-baseline: middle;
  pointer-events: none;
}
.mobius-curve-name,
.mobius-boundary-name {
  font: 900 12px/1 Inter, ui-rounded, sans-serif;
  text-anchor: middle;
  dominant-baseline: middle;
  paint-order: stroke;
  stroke: rgba(255,255,255,.96);
  stroke-width: 4px;
  stroke-linejoin: round;
  pointer-events: none;
}
.mobius-curve-name { fill: currentColor; }
.mobius-boundary-name,
.mobius-cover-boundary-name { fill: #66606d; }
.mobius-cover-curve-name,
.mobius-cover-boundary-name { font-size: 11px; }
.mobius-math-base,
.mobius-math-accent,
.mobius-math-subscript {
  paint-order: stroke;
  stroke: rgba(255,255,255,.96);
  stroke-width: 4px;
  stroke-linejoin: round;
}
.mobius-math-accent { font-size: .82em; }
.mobius-math-subscript {
  font-size: .7em;
  baseline-shift: sub;
}
.mobius-lift-number-bg { fill: rgba(255,255,255,.9); stroke-width: 1.4; }
.mobius-lift-number {
  font: 900 12px/1 Inter, ui-rounded, sans-serif;
  text-anchor: middle;
  dominant-baseline: middle;
  pointer-events: none;
}
.mobius-involution-guide {
  fill: none;
  stroke: color-mix(in srgb, var(--mobius-violet) 42%, transparent);
  stroke-width: 1.4;
  stroke-dasharray: 5 7;
}

.mobius-arc-register {
  margin-top: 14px;
  padding: 20px;
  border-color: color-mix(in srgb, var(--mobius-violet) 22%, transparent);
}
.mobius-register-stats {
  display: flex;
  gap: 7px;
  flex-wrap: wrap;
  justify-content: flex-end;
}
.mobius-register-stats span {
  padding: 7px 9px;
  border-radius: 10px;
  color: var(--muted);
  background: var(--mobius-soft);
  font-size: .7rem;
  font-weight: 800;
}
.mobius-register-stats strong { color: var(--mobius-violet); }
.mobius-topology-summary {
  margin-top: 12px;
  padding: 12px 14px;
  border-radius: 16px;
  background: color-mix(in srgb, var(--mobius-violet) 5%, var(--panel));
  border: 1px solid color-mix(in srgb, var(--mobius-violet) 18%, transparent);
}
.mobius-triangulation-badge {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 7px 10px;
  border-radius: 999px;
  font-size: .72rem;
  font-weight: 900;
  color: var(--muted);
  background: color-mix(in srgb, var(--muted) 10%, transparent);
  border: 1px solid color-mix(in srgb, var(--muted) 24%, transparent);
}
.mobius-triangulation-badge.is-triangulation {
  color: color-mix(in srgb, var(--good) 82%, var(--ink));
  background: color-mix(in srgb, var(--good) 12%, var(--panel));
  border-color: color-mix(in srgb, var(--good) 36%, transparent);
}
.mobius-triangulation-badge.is-compatible {
  color: color-mix(in srgb, #b07b16 88%, var(--ink));
  background: color-mix(in srgb, #e7a83a 12%, var(--panel));
  border-color: color-mix(in srgb, #d99524 36%, transparent);
}
.mobius-triangulation-badge.is-invalid {
  color: color-mix(in srgb, var(--bad) 88%, var(--ink));
  background: color-mix(in srgb, var(--bad) 8%, var(--panel));
  border-color: color-mix(in srgb, var(--bad) 28%, transparent);
}
.mobius-topology-note {
  margin: 10px 0 0;
  color: var(--muted);
  line-height: 1.48;
  font-size: .8rem;
}
.mobius-cover-intersection {
  fill: #10152a;
  stroke: #ffffff;
  stroke-width: 1.9;
}
.mobius-cover-intersection.is-active {
  fill: #d9480f;
  stroke: #fff7eb;
}
.mobius-arc-list { display: grid; gap: 8px; margin-top: 14px; }
.mobius-empty-state {
  margin: 0;
  padding: 22px;
  border-radius: 16px;
  color: var(--muted);
  background: color-mix(in srgb, var(--muted) 6%, transparent);
  border: 1px dashed color-mix(in srgb, var(--muted) 24%, transparent);
  text-align: center;
  font-size: .82rem;
}
.mobius-arc-row {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto auto;
  align-items: center;
  gap: 11px;
  padding: 10px 11px;
  border-radius: 15px;
  background: color-mix(in srgb, var(--arc-color) 7%, var(--panel));
  border: 1px solid color-mix(in srgb, var(--arc-color) 25%, transparent);
  cursor: pointer;
  transition: border-color .15s ease, transform .15s ease, background .15s ease;
}
.mobius-arc-row:hover,
.mobius-arc-row:focus-within,
.mobius-arc-row.is-active {
  transform: translateY(-1px);
  background: color-mix(in srgb, var(--arc-color) 12%, var(--panel));
  border-color: color-mix(in srgb, var(--arc-color) 58%, transparent);
}
.mobius-arc-swatch {
  width: 14px;
  height: 36px;
  border-radius: 999px;
  background: var(--arc-color);
  box-shadow: 0 4px 10px color-mix(in srgb, var(--arc-color) 30%, transparent);
}
.mobius-arc-copy { min-width: 0; }
.mobius-arc-copy strong { display: block; margin-bottom: 2px; font-size: .86rem; }
.mobius-arc-copy small { display: block; color: var(--muted); line-height: 1.35; }
.mobius-lift-badge {
  padding: 6px 8px;
  border-radius: 9px;
  color: color-mix(in srgb, var(--arc-color) 88%, var(--ink));
  background: color-mix(in srgb, var(--arc-color) 10%, transparent);
  font-size: .68rem;
  font-weight: 900;
  white-space: nowrap;
}
.mobius-remove-arc {
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  padding: 0;
  border-radius: 10px;
  border: 1px solid color-mix(in srgb, var(--bad) 24%, transparent);
  color: var(--bad);
  background: color-mix(in srgb, var(--bad) 7%, var(--panel));
  font-size: 1rem;
  font-weight: 900;
}
.mobius-remove-arc:hover { background: color-mix(in srgb, var(--bad) 14%, var(--panel)); }
.mobius-method-note {
  margin-top: 14px;
  padding: 18px 20px;
  border-color: color-mix(in srgb, var(--mobius-violet) 20%, transparent);
}
.mobius-method-note summary {
  color: color-mix(in srgb, var(--mobius-violet) 84%, var(--ink));
  font-weight: 900;
  cursor: pointer;
}
.mobius-method-note p {
  margin: 12px 0 0;
  color: var(--muted);
  line-height: 1.55;
  font-size: .82rem;
}

@media (max-width: 900px) {
  .mobius-controls { grid-template-columns: 1fr 1fr; }
  .mobius-point-count-control { grid-column: 1 / -1; }
  .mobius-diagram-grid { grid-template-columns: 1fr; }
  .mobius-diagram-card { padding: 16px; }
  .mobius-diagram { width: min(100%, 560px); }
}
@media (max-width: 620px) {
  .standalone-shell { width: min(100% - 18px, 1180px); padding-top: 12px; }
  .app-header { align-items: flex-start; padding: 0 4px; }
  .app-header-actions { align-items: flex-end; flex-direction: column-reverse; }
  .app-brand-symbol { width: 42px; height: 42px; border-radius: 13px; font-size: 1.45rem; }
  .offline-badge { display: none; }
  .panel { border-radius: 19px; }
  .mobius-hero { grid-template-columns: auto 1fr; padding: 18px; gap: 14px; }
  .mobius-hero-symbol { width: 58px; height: 58px; border-radius: 18px; font-size: 2rem; }
  .mobius-reference-badge { grid-column: 1 / -1; justify-self: start; }
  .mobius-controls { grid-template-columns: 1fr; padding: 12px; }
  .mobius-point-count-control,
  .mobius-control-actions,
  .mobius-status { grid-column: auto; }
  .mobius-control-actions { justify-content: stretch; }
  .mobius-control-actions button { flex: 1 1 140px; }
  .mobius-register-heading { display: grid; }
  .mobius-register-stats { justify-content: flex-start; }
  .mobius-arc-row { grid-template-columns: auto minmax(0, 1fr) auto; }
  .mobius-lift-badge { grid-column: 2; justify-self: start; }
  .mobius-remove-arc { grid-column: 3; grid-row: 1 / 3; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .secondary-button,
  .danger-button,
  .mobius-mark,
  .mobius-arc-path,
  .mobius-arc-row,
  .mobius-segmented button { transition: none; }
}

/* Crosscap interaction and the one-sided quasi-arc. */
.mobius-crosscap-group { cursor: pointer; outline: none; }
.mobius-crosscap-hit { fill: transparent; }
.mobius-crosscap-halo {
  fill: color-mix(in srgb, #d12d48 20%, transparent);
  stroke: color-mix(in srgb, #d12d48 55%, transparent);
  stroke-width: 2;
}
.mobius-crosscap-group:hover .mobius-crosscap-disc,
.mobius-crosscap-group:focus-visible .mobius-crosscap-disc,
.mobius-crosscap-group.is-selected .mobius-crosscap-disc {
  stroke: #d12d48;
  stroke-width: 4;
  filter: drop-shadow(0 0 6px rgba(209,45,72,.45));
}
.mobius-quasi-arc-path,
.mobius-quasi-lift-path { stroke-width: 6.5; }
.mobius-arc-group { outline: none; }

/* Snake graph panel */
.mobius-snake-panel {
  margin-top: 14px;
  padding: 20px;
  border-color: color-mix(in srgb, var(--mobius-violet) 24%, transparent);
}
.mobius-snake-heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 14px;
}
.mobius-snake-heading h3 { margin: 0; font-size: 1.18rem; }
.mobius-snake-heading .eyebrow { margin-bottom: 4px; }
.mobius-snake-status {
  margin: 12px 0 0;
  color: var(--muted);
  line-height: 1.5;
  font-size: .84rem;
}
.mobius-snake-status.is-warning { color: #8a4b0f; }
.mobius-snake-status.is-success { color: color-mix(in srgb, var(--good) 82%, var(--ink)); }
.mobius-snake-controls {
  display: grid;
  grid-template-columns: minmax(220px, 1fr) minmax(280px, 1.2fr) minmax(180px, .9fr);
  gap: 14px;
  margin-top: 14px;
}
.mobius-snake-field {
  display: grid;
  gap: 7px;
  min-width: 0;
}
.mobius-snake-field > span {
  color: var(--muted);
  font-size: .72rem;
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: .04em;
}
.mobius-snake-field select {
  width: 100%;
  min-height: 42px;
  padding: 8px 10px;
  border-radius: 12px;
  border: 1px solid color-mix(in srgb, var(--mobius-violet) 24%, transparent);
  color: var(--ink);
  background: var(--panel);
  font: inherit;
  font-size: .82rem;
  font-weight: 750;
}
.mobius-snake-toggle-field { align-content: end; }
.mobius-snake-inline-toggle {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 42px;
  padding: 8px 12px;
  border-radius: 12px;
  border: 1px solid color-mix(in srgb, var(--mobius-violet) 24%, transparent);
  color: var(--ink);
  background: var(--panel);
  font-size: .82rem;
  font-weight: 750;
  text-transform: none;
  letter-spacing: 0;
}
.mobius-snake-inline-toggle input {
  width: 16px;
  height: 16px;
  accent-color: var(--mobius-violet);
}
.mobius-snake-inline-toggle input:disabled { opacity: .45; }
.mobius-snake-inline-toggle:has(input:disabled) {
  opacity: .6;
  cursor: not-allowed;
}
.mobius-snake-graph-wrap {
  margin-top: 16px;
  overflow: auto;
  border-radius: 16px;
  border: 1px solid color-mix(in srgb, var(--mobius-violet) 18%, transparent);
  background:
    linear-gradient(color-mix(in srgb, var(--mobius-violet) 3%, transparent), color-mix(in srgb, var(--mobius-violet) 3%, transparent)),
    var(--panel);
}
.mobius-graph-reading-guide {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 14px;
  padding: 12px 14px;
  border-bottom: 1px solid color-mix(in srgb, var(--mobius-violet) 16%, transparent);
  color: var(--muted);
  background: color-mix(in srgb, var(--mobius-violet) 4%, var(--panel));
  font-size: .72rem;
  line-height: 1.4;
}
.mobius-graph-reading-guide span { display: inline-flex; align-items: center; gap: 7px; }
.mobius-graph-reading-guide i { display: inline-block; flex: 0 0 auto; }
.guide-tile { width: 15px; height: 15px; border: 2px solid #2b2832; border-radius: 3px; background: #fff; }
.guide-diagonal { width: 20px; border-top: 3px dashed #d12d48; transform: rotate(25deg); }
.guide-glue { width: 20px; border-top: 5px solid #168349; border-radius: 999px; }
.guide-match { width: 20px; border-top: 5px solid #c69214; border-radius: 999px; }
.guide-cut { width: 20px; border-top: 5px solid #1769aa; border-radius: 999px; }
.mobius-snake-graph {
  display: block;
  min-width: 100%;
  min-height: 250px;
}
.mobius-snake-tile {
  fill: rgba(255,255,255,.92);
  stroke: #2b2832;
  stroke-width: 2.1;
}
.mobius-snake-tile-number {
  fill: #2b2832;
  font: 900 13px/1 Inter, ui-rounded, sans-serif;
  text-anchor: middle;
  dominant-baseline: middle;
}
.mobius-snake-diagonal {
  fill: none;
  stroke-width: 3;
  stroke-dasharray: 7 5;
  stroke-linecap: round;
}
.mobius-snake-diagonal-label {
  font: 900 11px/1 Inter, ui-rounded, sans-serif;
  text-anchor: middle;
  dominant-baseline: middle;
  paint-order: stroke;
  stroke: rgba(255,255,255,.95);
  stroke-width: 4px;
  stroke-linejoin: round;
}
.mobius-snake-edge-label {
  fill: #625c69;
  font: 800 9px/1 Inter, ui-rounded, sans-serif;
  text-anchor: middle;
  dominant-baseline: middle;
  paint-order: stroke;
  stroke: rgba(255,255,255,.98);
  stroke-width: 3px;
  stroke-linejoin: round;
  pointer-events: none;
}
.mobius-snake-glue-edge {
  stroke: var(--mobius-violet);
  stroke-width: 5;
  stroke-linecap: round;
}
.mobius-snake-sequence {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  margin-top: 12px;
}
.mobius-snake-sequence:empty { display: none; }
.mobius-snake-chip {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 6px 8px;
  border-radius: 10px;
  color: var(--ink);
  background: color-mix(in srgb, var(--mobius-violet) 8%, var(--panel));
  border: 1px solid color-mix(in srgb, var(--mobius-violet) 18%, transparent);
  font-size: .7rem;
  font-weight: 850;
}
.mobius-snake-chip i {
  width: 8px;
  height: 8px;
  border-radius: 999px;
  background: var(--chip-color, var(--mobius-violet));
}
.mobius-arc-group.is-snake-target .mobius-arc-path {
  stroke-width: 7.5;
  filter: drop-shadow(0 0 7px currentColor);
}
.mobius-arc-group.is-snake-reference .mobius-arc-path { opacity: 1; }
.mobius-arc-group.is-snake-other:not(.is-snake-target) .mobius-arc-path { opacity: .22; }
.mobius-arc-path.is-snake-candidate { cursor: pointer; }
.mobius-arc-path.is-snake-selected {
  stroke-width: 9;
  filter: drop-shadow(0 0 8px currentColor);
}
.mobius-arc-path.is-snake-unselected { opacity: .24; }

.mobius-snake-tile-group { cursor: default; }
.mobius-snake-tile-header {
  fill: #2b2832;
  font: 900 12px/1 Inter, ui-rounded, sans-serif;
  text-anchor: start;
  dominant-baseline: middle;
}
.mobius-snake-diagonal-pill {
  fill: rgba(255,255,255,.94);
  stroke: rgba(43,40,50,.13);
  stroke-width: 1;
}
.mobius-snake-diagonal-caption {
  fill: #746d79;
  font: 750 8px/1 Inter, ui-rounded, sans-serif;
  text-anchor: middle;
  dominant-baseline: middle;
  text-transform: uppercase;
  letter-spacing: .04em;
}
.mobius-snake-edge-label.is-west { text-anchor: end; }
.mobius-snake-edge-label.is-east { text-anchor: start; }
.mobius-snake-matching-edge {
  stroke: #c69214;
  stroke-width: 8;
  stroke-linecap: round;
}
.mobius-snake-glue-edge {
  stroke: #168349;
  stroke-width: 6;
  stroke-linecap: round;
}
.mobius-band-cut-edge {
  stroke: #1769aa;
  stroke-width: 7;
  stroke-linecap: round;
}
.mobius-band-cut-label {
  fill: #1769aa;
  font: 950 15px/1 Inter, ui-rounded, sans-serif;
  text-anchor: middle;
  paint-order: stroke;
  stroke: #fff;
  stroke-width: 5px;
}
.mobius-band-closure {
  fill: none;
  stroke: #1769aa;
  stroke-width: 2.6;
  stroke-dasharray: 7 6;
}
.mobius-band-arrow-head { fill: #1769aa; }
.mobius-band-closure-label {
  fill: #1769aa;
  font: 900 11px/1 Inter, ui-rounded, sans-serif;
  text-anchor: middle;
  paint-order: stroke;
  stroke: #fff;
  stroke-width: 5px;
}
.mobius-snake-empty-title {
  fill: #2b2832;
  font: 900 18px/1 Inter, ui-rounded, sans-serif;
  text-anchor: middle;
}
.mobius-snake-empty-note {
  fill: #746d79;
  font: 750 11px/1 Inter, ui-rounded, sans-serif;
  text-anchor: middle;
}
.mobius-snake-tile-details {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 9px;
  padding: 0 14px 14px;
}
.mobius-snake-tile-details:empty { display: none; }
.mobius-snake-tile-card {
  display: grid;
  gap: 5px;
  padding: 10px 12px;
  border-radius: 12px;
  border: 1px solid color-mix(in srgb, var(--tile-color, var(--mobius-violet)) 26%, transparent);
  border-left: 5px solid var(--tile-color, var(--mobius-violet));
  background: color-mix(in srgb, var(--tile-color, var(--mobius-violet)) 5%, var(--panel));
  font-size: .76rem;
  line-height: 1.42;
}
.mobius-snake-tile-card strong { color: var(--ink); }
.mobius-snake-tile-card span { color: color-mix(in srgb, var(--tile-color, var(--mobius-violet)) 80%, var(--ink)); }
.mobius-snake-tile-card small { color: var(--muted); }
.mobius-snake-tile-card.is-cut-card {
  --tile-color: #1769aa;
}

@media (max-width: 760px) {
  .mobius-snake-controls { grid-template-columns: 1fr; }
  .mobius-snake-heading { display: grid; }
}
.mobius-lift-hit {
  fill: none;
  stroke: transparent;
  stroke-width: 22;
  pointer-events: stroke;
  cursor: pointer;
}

.mobius-seed-actions,
.mobius-3d-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
}
.mobius-seed-actions { margin-top: 12px; }
.primary-button {
  border: 1px solid var(--mobius-violet);
  color: #fff;
  background: var(--mobius-violet);
  box-shadow: 0 8px 20px color-mix(in srgb, var(--mobius-violet) 18%, transparent);
}
.primary-button:hover:not(:disabled) {
  background: color-mix(in srgb, var(--mobius-violet) 84%, #17111f);
}
.primary-button:disabled,
.secondary-button:disabled {
  cursor: not-allowed;
  opacity: .48;
  box-shadow: none;
}
.secondary-button.compact {
  min-height: 34px;
  padding: 7px 10px;
  font-size: .72rem;
}

.mobius-cluster-panel,
.mobius-3d-panel {
  display: grid;
  gap: 16px;
  margin-top: 14px;
  padding: 20px;
  border-color: color-mix(in srgb, var(--mobius-violet) 24%, transparent);
}
.mobius-cluster-panel.hidden,
.mobius-3d-panel.hidden,
.mobius-gvector-panel.hidden {
  display: none;
}
.mobius-cluster-heading,
.mobius-card-heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 14px;
}
.mobius-cluster-heading h3,
.mobius-cluster-card h4,
.mobius-relation-card h4,
.mobius-gvector-panel h4 {
  margin: 0;
}
.mobius-cluster-grid {
  display: grid;
  grid-template-columns: minmax(220px, .72fr) minmax(0, 1.55fr);
  gap: 14px;
}
.mobius-cluster-card,
.mobius-relation-card,
.mobius-gvector-panel {
  padding: 15px;
  border-radius: 16px;
  border: 1px solid color-mix(in srgb, var(--mobius-violet) 18%, transparent);
  background: color-mix(in srgb, var(--mobius-violet) 3.5%, var(--panel));
}
.mobius-variable-list,
.mobius-mutation-list,
.mobius-gvector-results {
  display: grid;
  gap: 8px;
  margin-top: 11px;
}
.mobius-variable-row,
.mobius-mutation-row,
.mobius-gvector-result {
  display: grid;
  align-items: center;
  gap: 10px;
  padding: 10px 11px;
  border-radius: 12px;
  border: 1px solid color-mix(in srgb, var(--row-color, var(--mobius-violet)) 22%, transparent);
  background: color-mix(in srgb, var(--row-color, var(--mobius-violet)) 4%, var(--panel));
}
.mobius-variable-row {
  grid-template-columns: auto 1fr;
}
.mobius-mutation-row {
  grid-template-columns: auto minmax(0, 1fr) auto;
}
.mobius-variable-symbol {
  display: inline-grid;
  min-width: 42px;
  min-height: 34px;
  place-items: center;
  border-radius: 10px;
  color: #fff;
  background: var(--row-color, var(--mobius-violet));
  font-family: "Cambria Math", "STIX Two Math", Georgia, serif;
  font-weight: 900;
}
.mobius-variable-copy {
  min-width: 0;
}
.mobius-variable-copy strong,
.mobius-variable-copy small {
  display: block;
}
.mobius-variable-copy small {
  margin-top: 3px;
  overflow-wrap: anywhere;
  color: var(--muted);
  font-family: "Cambria Math", "STIX Two Math", Georgia, serif;
  font-size: .76rem;
  line-height: 1.42;
}
.mobius-mutate-button {
  min-height: 38px;
  white-space: nowrap;
}
.mobius-relation-card {
  border-left: 5px solid var(--mobius-violet);
}
.mobius-math-expression,
.mobius-math-value {
  margin: 9px 0 0;
  overflow-wrap: anywhere;
  color: var(--ink);
  font-family: "Cambria Math", "STIX Two Math", Georgia, serif;
  font-size: clamp(.92rem, 2vw, 1.08rem);
  line-height: 1.55;
}
.mobius-math-value {
  color: var(--muted);
  font-size: .88rem;
}
.mobius-history summary {
  cursor: pointer;
  font-weight: 850;
}
.mobius-history ol {
  display: grid;
  gap: 7px;
  margin: 10px 0 0;
  padding-left: 25px;
  color: var(--muted);
  font: 750 .8rem/1.5 "Cambria Math", "STIX Two Math", Georgia, serif;
}

.mobius-gvector-panel {
  display: grid;
  gap: 8px;
  margin: 14px 0 0;
  border-left: 5px solid #c69214;
}
.mobius-gvector-results {
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
}
.mobius-gvector-result {
  --row-color: #c69214;
}
.mobius-gvector-result.is-primary {
  --row-color: #168349;
}
.mobius-gvector-result strong,
.mobius-gvector-result span,
.mobius-gvector-result small {
  display: block;
}
.mobius-gvector-result span {
  margin: 4px 0;
  font: 900 1.02rem/1.35 "Cambria Math", "STIX Two Math", Georgia, serif;
}
.mobius-gvector-result small {
  color: var(--muted);
  line-height: 1.45;
}

.mobius-3d-stage {
  position: relative;
  min-height: 380px;
  overflow: hidden;
  border-radius: 18px;
  border: 1px solid color-mix(in srgb, var(--mobius-violet) 22%, transparent);
  background:
    radial-gradient(circle at 50% 42%, rgba(255,255,255,.98), rgba(242,238,249,.92) 62%, rgba(224,217,239,.9));
}
#mobius3dCanvas {
  display: block;
  width: 100%;
  height: min(62vw, 520px);
  min-height: 380px;
  touch-action: none;
  cursor: grab;
}
#mobius3dCanvas:active { cursor: grabbing; }
#mobius3dCanvas:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--mobius-violet) 60%, #fff);
  outline-offset: -4px;
}
.mobius-3d-controls {
  justify-content: center;
}
.mobius-3d-controls button {
  min-width: 44px;
  min-height: 40px;
  border: 1px solid color-mix(in srgb, var(--mobius-violet) 25%, transparent);
  border-radius: 11px;
  color: var(--ink);
  background: var(--panel);
  font: 850 .82rem/1 inherit;
}
.mobius-3d-controls button:hover {
  border-color: var(--mobius-violet);
  color: var(--mobius-violet);
}
.mobius-3d-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.mobius-3d-legend span {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 7px 9px;
  border-radius: 10px;
  border: 1px solid color-mix(in srgb, var(--legend-color, var(--mobius-violet)) 24%, transparent);
  background: color-mix(in srgb, var(--legend-color, var(--mobius-violet)) 5%, var(--panel));
  color: var(--ink);
  font-size: .76rem;
  font-weight: 800;
}
.mobius-3d-legend i {
  width: 19px;
  border-top: 4px solid var(--legend-color, var(--mobius-violet));
  border-radius: 999px;
}

.mobius-lab-screen.is-seed-locked [data-mobius-mark],
.mobius-lab-screen.is-seed-locked [data-mobius-crosscap],
.mobius-lab-screen.is-seed-locked [data-mobius-remove] {
  pointer-events: none;
}
.mobius-lab-screen.is-seed-locked .mobius-remove-arc {
  visibility: hidden;
}

@media (max-width: 820px) {
  .mobius-cluster-grid { grid-template-columns: 1fr; }
  .mobius-cluster-heading,
  .mobius-card-heading { align-items: stretch; flex-direction: column; }
}
@media (max-width: 560px) {
  .mobius-mutation-row {
    grid-template-columns: auto minmax(0, 1fr);
  }
  .mobius-mutate-button {
    grid-column: 1 / -1;
    width: 100%;
  }
  #mobius3dCanvas,
  .mobius-3d-stage {
    min-height: 310px;
  }
}