:root {
  --bg: #f1f3f6;
  --panel: #ffffff;
  --panel-alt: #edf1f6;
  --text: #1c2430;
  --muted: #6c7788;
  --accent: #0e8f65;
  --accent-2: #2b6de4;
  --accent-3: #7c3aed;
  --border: #d9e0ea;
  --shadow: 0 12px 24px rgba(17, 28, 45, 0.08);
}

body.dark {
  --bg: #0f1721;
  --panel: #172233;
  --panel-alt: #101927;
  --text: #eef4ff;
  --muted: #96a4ba;
  --accent: #31c692;
  --accent-2: #69a6ff;
  --accent-3: #b078ff;
  --border: #27364c;
  --shadow: 0 16px 28px rgba(0, 0, 0, 0.35);
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

html {
  height: 100%;
}

body {
  margin: 0;
  padding: 0;
  min-height: 100%;
  font-family: "Space Grotesk", sans-serif;
  background: var(--bg);
  color: var(--text);
}

.app {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: radial-gradient(circle at 20% 0%, rgba(50, 130, 240, 0.08), transparent 30%), transparent;
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 18px;
  border-bottom: 1px solid var(--border);
  background: color-mix(in oklab, var(--panel), transparent 5%);
  position: sticky;
  top: 0;
  z-index: 200;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.brand {
  display: flex;
  gap: 12px;
  align-items: center;
}

.brand-mark {
  width: 34px;
  height: 34px;
  border-radius: 10px;
  background: linear-gradient(140deg, var(--accent), var(--accent-2));
  display: grid;
  place-items: center;
  overflow: hidden;
}

.brand-mark img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.brand h1 {
  font-size: 1.25rem;
  line-height: 1;
  margin: 0;
}

.brand p {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 0.85rem;
}

.top-actions {
  position: relative;
  display: flex;
  gap: 10px;
}

.restore-btn {
  border-style: dashed;
}

/* Undo / Redo row in the gate library panel */
.lib-undo-row {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: 4px;
}

.lib-undo-row .icon-btn {
  flex-shrink: 0;
}

.undo-btn {
  color: #f06262;
  border-color: color-mix(in oklab, #f06262, var(--border) 52%);
  background: color-mix(in oklab, #f06262, var(--panel-alt) 80%);
}

.redo-btn {
  color: #2fbf71;
  border-color: color-mix(in oklab, #2fbf71, var(--border) 52%);
  background: color-mix(in oklab, #2fbf71, var(--panel-alt) 80%);
}

.layout {
  display: grid;
  grid-template-columns: minmax(220px, 260px) minmax(520px, 1fr) minmax(260px, 320px);
  gap: 12px;
  padding: 12px;
  flex: 1;
  min-height: max(calc(100vh - 120px), 780px);
  overflow: visible;
}

/* All three panels stretch to fill the grid row */
.left-panel,
.center-panel,
.right-panel {
  min-height: 0;
  overflow: visible;
}

.site-footer {
  border-top: 1px solid var(--border);
  padding: 12px 14px;
  text-align: center;
  color: var(--muted);
  font-size: 0.82rem;
  background: linear-gradient(0deg, color-mix(in oklab, var(--accent-2), transparent 94%), transparent);
}

.site-footer p {
  margin: 0;
  letter-spacing: 0.01em;
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 16px;
  box-shadow: var(--shadow);
  overflow: visible;
  transition: box-shadow 200ms ease;
}

.panel:hover {
  box-shadow: var(--shadow), 0 0 0 1px color-mix(in oklab, var(--accent-2), transparent 82%);
}

.left-panel,
.right-panel {
  padding: 14px;
}

.center-panel {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 10px;
  overflow: visible;
}

.circuit-wrap {
  position: relative;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: linear-gradient(180deg, color-mix(in oklab, var(--panel-alt), transparent 40%), transparent);
  min-height: 260px;
  overflow: hidden;
}

.panel-head h2 {
  margin: 0;
  font-size: 1rem;
}

.panel-head p {
  margin: 4px 0 12px;
  color: var(--muted);
  font-size: 0.86rem;
}

.gate-library {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin-bottom: 12px;
}

.left-controls {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 10px;
}

.control-label {
  font-size: 0.78rem;
  color: var(--muted);
}

.preset-select {
  width: 100%;
  height: 36px;
  border-radius: 10px;
  border: 1px solid var(--border);
  appearance: none;
  -webkit-appearance: none;
  -moz-appearance: none;
  background-color: var(--panel-alt);
  background-image:
    linear-gradient(45deg, transparent 50%, var(--muted) 50%),
    linear-gradient(135deg, var(--muted) 50%, transparent 50%);
  background-position:
    calc(100% - 16px) 15px,
    calc(100% - 11px) 15px;
  background-size: 5px 5px, 5px 5px;
  background-repeat: no-repeat;
  color: var(--text);
  padding: 0 34px 0 10px;
  font-family: "IBM Plex Mono", monospace;
}

.gate-card {
  border: 2px solid var(--gate-color, var(--border));
  border-radius: 12px;
  height: 58px;
  max-height: 68px;
  width: 100%;
  background: var(--panel-alt);
  color: var(--text);
  cursor: grab;
  user-select: none;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2px;
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  box-shadow: inset 0 0 0 1px color-mix(in oklab, var(--gate-color, var(--border)), transparent 72%);
  transition: transform 120ms ease, box-shadow 180ms ease, filter 180ms ease;
}
.gate-card-symbol {
  font-weight: 700;
  font-size: 0.9rem;
}
.gate-card-name {
  font-size: 0.6rem;
  color: var(--muted);
  text-align: center;
  line-height: 1.1;
  max-width: 100%;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  padding: 0 4px;
}

.gate-card:hover {
  transform: translateY(-2px);
  filter: brightness(1.06);
  box-shadow:
    0 0 0 2px color-mix(in oklab, var(--gate-color, var(--border)), transparent 45%),
    0 0 22px color-mix(in oklab, var(--gate-color, var(--border)), transparent 52%),
    inset 0 0 12px color-mix(in oklab, var(--gate-color, var(--border)), transparent 84%);
}

.gate-card:active {
  cursor: grabbing;
}

.stats {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 18px;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--panel-alt);
}

.stat-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  white-space: nowrap;
}

.stat-divider {
  color: var(--muted);
}

.depth-edit-btn {
  width: 24px;
  height: 24px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: color-mix(in oklab, var(--panel), transparent 8%);
  color: var(--muted);
  display: inline-grid;
  place-items: center;
  cursor: pointer;
  margin-left: 6px;
  transition: transform 120ms ease, color 120ms ease, border-color 120ms ease;
}

.depth-edit-btn:hover {
  color: var(--text);
  border-color: var(--accent-2);
  transform: translateY(-1px);
}

.depth-edit-btn:focus-visible,
.gate-card:focus-visible,
.btn:focus-visible,
.preset-select:focus-visible {
  outline: 2px solid var(--accent-2);
  outline-offset: 2px;
}


.state-readout {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 8px 10px;
  background: color-mix(in oklab, var(--panel-alt), transparent 20%);
  font-size: 0.78rem;
  color: var(--muted);
}

.readout-title {
  display: block;
  font-size: 0.72rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 4px;
}

.readout-plain {
  display: block;
  color: var(--text);
  font-size: 0.88rem;
  line-height: 1.5;
  margin-bottom: 5px;
}

.readout-math {
  display: block;
  color: var(--muted);
  font-size: 0.72rem;
  margin-bottom: 3px;
  word-break: break-all;
}

.readout-history {
  display: block;
  color: var(--muted);
  font-size: 0.76rem;
}

/* Circuit Pattern Callout */
.circuit-pattern {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  margin: 10px 0 0;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid color-mix(in oklab, var(--accent), transparent 55%);
  background: color-mix(in oklab, var(--accent), transparent 88%);
  animation: pattern-pop 280ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

@keyframes pattern-pop {
  from { opacity: 0; transform: scale(0.97) translateY(4px); }
  to   { opacity: 1; transform: scale(1) translateY(0); }
}

.circuit-pattern-emoji {
  font-size: 1.3rem;
  line-height: 1;
  flex-shrink: 0;
  margin-top: 1px;
}

.circuit-pattern-title {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 3px;
}

.circuit-pattern-body {
  font-size: 0.83rem;
  color: var(--muted);
  line-height: 1.5;
}

.qubit-badge {
  position: absolute;
  left: 12px;
  top: 50%; /* fallback before JS kicks in */
  transform: translateY(-50%);
  min-width: 44px;
  height: 44px;
  padding: 0 10px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: color-mix(in oklab, var(--panel), transparent 8%);
  color: var(--text);
  font-size: 0.9rem;
  font-weight: 700;
  display: grid;
  place-items: center;
  box-shadow: 0 6px 14px rgba(0, 0, 0, 0.12);
  pointer-events: none;
  transition: top 120ms ease;
}

.explain-box {
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: 14px;
  padding: 12px;
  background: linear-gradient(125deg, color-mix(in oklab, var(--accent), transparent 90%), transparent);
  transition: border-color 300ms ease, background 300ms ease;
}

.explain-box.empty {
  min-height: 60px;
  background: transparent;
  border-style: dashed;
  border-left-style: dashed;
}

.explain-box h3 {
  margin: 0;
  font-size: 0.95rem;
}

.explain-box > p {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.55;
}

.state-card {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 10px;
  margin-bottom: 12px;
  background: var(--panel-alt);
}

.state-vector-card {
  background: linear-gradient(180deg, color-mix(in oklab, var(--panel-alt), white 6%), var(--panel-alt));
}

.state-card h3 {
  margin: 0 0 10px;
  font-size: 0.95rem;
}

.amplitude-block {
  padding: 8px;
  border-radius: 10px;
  border: 1px solid color-mix(in oklab, var(--border), transparent 20%);
  background: color-mix(in oklab, var(--panel), transparent 15%);
}

.amplitude-block + .amplitude-block {
  margin-top: 8px;
}

.amplitude-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  font-size: 0.82rem;
}

.amplitude-row span:last-child {
  color: var(--muted);
  font-size: 0.75rem;
  text-align: right;
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 2px;
}

.amp-value {
  color: var(--text);
  font-size: 0.75rem;
}

.amp-prob {
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 700;
}

/* Circuit Impact Box */
.circuit-impact {
  margin-top: 10px;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid color-mix(in oklab, var(--accent-2), transparent 68%);
  background: color-mix(in oklab, var(--accent-2), transparent 92%);
}

.circuit-impact-label {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--accent-2);
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 5px;
}

.circuit-impact-body {
  margin: 0 0 6px;
  font-size: 0.87rem;
  color: var(--text);
  line-height: 1.55;
}

.circuit-impact-body:last-child {
  margin-bottom: 0;
}

.circuit-impact-summary {
  margin: 0;
  font-size: 0.82rem;
  color: var(--muted);
  line-height: 1.5;
  border-top: 1px solid color-mix(in oklab, var(--border), transparent 30%);
  padding-top: 6px;
}

.bar-track {
  height: 10px;
  background: color-mix(in oklab, var(--panel), black 8%);
  border-radius: 99px;
  overflow: hidden;
  margin-top: 8px;
}

.bar-fill {
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--accent), var(--accent-2), color-mix(in oklab, var(--accent), var(--accent-2) 50%));
  background-size: 200% 100%;
  box-shadow: 0 0 16px color-mix(in oklab, var(--accent-2), transparent 40%);
  transition: width 520ms cubic-bezier(0.2, 0.8, 0.2, 1);
  animation: bar-shimmer 3s linear infinite;
}

@keyframes bar-shimmer {
  0%   { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

.bloch-wrap {
  width: 100%;
  min-height: 210px;
  border-radius: 12px;
  border: 1px solid var(--border);
  overflow: hidden;
}

.bloch-coords {
  margin-top: 8px;
  font-size: 0.78rem;
  color: var(--muted);
}

.sequence {
  font-size: 0.84rem;
  color: var(--muted);
  max-height: 120px;
  overflow-y: auto;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 8px 12px;
  font-family: inherit;
  font-weight: 500;
  cursor: pointer;
  transition: transform 120ms ease, background 120ms ease;
}

.btn:hover {
  transform: translateY(-1px);
  filter: brightness(1.04);
}

.btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
  transform: none;
}

.btn-soft {
  background: var(--panel-alt);
  color: var(--text);
}

#guideBtn {
  background: linear-gradient(120deg, var(--accent), var(--accent-2));
  color: #fff;
  border-color: color-mix(in oklab, var(--accent-2), #ffffff 24%);
}

body.dark #guideBtn {
  background: linear-gradient(120deg, #23936f, #3e79cf);
  border-color: color-mix(in oklab, #3e79cf, #ffffff 20%);
}

#learnBtn {
  position: relative;
  z-index: 0;
  text-decoration: none;
  font-size: 0.875rem;
  border: none;
  border-radius: 10px;
  box-shadow:
    0 0 12px rgba(49, 198, 146, 0.25),
    0 0 24px rgba(105, 166, 255, 0.18),
    0 0 40px rgba(176, 120, 255, 0.12);
  background: linear-gradient(
  180deg,
  #22304a,
  #172233
  );
  
  color: white;

  overflow: hidden;
}

#learnBtn::before {
  content: "";

  position: absolute;
  top: -2px;
  left: -2px;

  width: calc(100% + 4px);
  height: calc(100% + 4px);

  border-radius: inherit;

  background: linear-gradient(
    90deg,
    #31c692,
    #69a6ff,
    #b078ff,
    #69a6ff,
    #31c692
  );

  background-size: 300%;

  filter: blur(6px);

  z-index: -2;

  animation: quantumGlow 8s linear infinite;
}

#learnBtn::after {
  content: "";

  position: absolute;
  inset: 2px;

  background: #172233;

  border-radius: 8px;

  z-index: -1;
}

@keyframes quantumGlow {
  0% {
    background-position: 0% 50%;
  }

  100% {
    background-position: 300% 50%;
  }
}

body:not(.dark) #learnBtn {
  background: linear-gradient(
    180deg,
    #ffffff,
    #f4f7fb
  );

  color: #1f2937;

  box-shadow:
    0 0 10px rgba(49, 198, 146, 0.12),
    0 0 18px rgba(105, 166, 255, 0.10),
    0 0 28px rgba(176, 120, 255, 0.08);
}

body:not(.dark) #learnBtn::after {
  background: linear-gradient(
    180deg,
    #ffffff,
    #f4f7fb
  );
}

.btn-primary {
  background: var(--text);
  color: var(--panel);
  border-color: color-mix(in oklab, var(--text), white 30%);
}


.icon-btn {
  width: 38px;
  height: 38px;
  display: grid;
  place-items: center;
  padding: 0;
}

.icon-btn i {
  font-size: 0.95rem;
}

.full {
  width: 100%;
}

.mono {
  font-family: "IBM Plex Mono", monospace;
}

.drag-ghost {
  position: fixed;
  left: 0;
  top: 0;
  width: 58px;
  height: 48px;
  border-radius: 12px;
  display: none;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1rem;
  pointer-events: none;
  z-index: 9999;
  backdrop-filter: blur(3px);
  transform: translate(-50%, -50%);
  transition: transform 80ms linear;
}

.adv-drag-ghost {
  position: fixed;
  left: 0;
  top: 0;
  max-width: 140px;
  padding: 6px 10px;
  border-radius: 10px;
  display: none;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 0.85rem;
  pointer-events: none;
  z-index: 9999;
  backdrop-filter: blur(4px);
  transform: translate(-50%, -50%);
  transition: transform 90ms ease-out;
  white-space: nowrap;
  text-overflow: ellipsis;
  overflow: hidden;
}

.gate-tooltip {
  position: fixed;
  left: 0;
  top: 0;
  padding: 8px 10px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: color-mix(in oklab, var(--panel), transparent 6%);
  color: var(--text);
  font-size: 0.78rem;
  font-weight: 600;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
  opacity: 0;
  pointer-events: none;
  z-index: 10000;
  transition: opacity 140ms ease;
  white-space: nowrap;
}

.gate-tooltip.visible {
  opacity: 1;
}

.action-tooltip {
  display: flex;
  align-items: center;
  gap: 8px;
  transform: translate(-50%, 8px);
  transition: opacity 260ms ease;
}

.action-tooltip.boxed {
  max-width: 260px;
  white-space: normal;
  padding: 10px 12px;
  border-radius: 12px;
  box-shadow: 0 14px 26px rgba(0, 0, 0, 0.24);
}

.export-overlay {
  position: fixed;
  inset: 0;
  background: color-mix(in oklab, var(--bg), transparent 45%);
  backdrop-filter: blur(7px);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  z-index: 12000;
  transition: opacity 260ms ease;
}

.export-overlay.visible {
  opacity: 1;
  pointer-events: all;
}

.export-card {
  width: min(520px, calc(100vw - 32px));
  border-radius: 14px;
  border: 1px solid var(--border);
  background: color-mix(in oklab, var(--panel), transparent 8%);
  box-shadow: 0 18px 40px rgba(0, 0, 0, 0.28);
  padding: 22px;
  text-align: center;
}

.export-card i {
  font-size: 1.4rem;
  color: var(--accent-2);
}

.export-card h3 {
  margin: 10px 0 6px;
  font-size: 1rem;
}

.export-card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.export-card .btn {
  margin-top: 14px;
}

.export-menu {
  position: absolute;
  right: 0;
  top: calc(100% + 8px);
  width: 200px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: color-mix(in oklab, var(--panel), transparent 3%);
  box-shadow: 0 12px 24px rgba(0, 0, 0, 0.22);
  padding: 8px;
  display: none;
  flex-direction: column;
  gap: 8px;
  z-index: 11000;
}

.export-menu.visible {
  display: flex;
}

.depth-backdrop {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 12490;
  background: rgba(0, 0, 0, 0.45);
  backdrop-filter: blur(2px);
}
.depth-backdrop.visible {
  display: block;
}

.depth-editor {
  position: fixed;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%) scale(0.96);
  width: min(360px, calc(100vw - 24px));
  border-radius: 14px;
  border: 1px solid var(--border);
  background: color-mix(in oklab, var(--panel), transparent 6%);
  box-shadow: 0 20px 36px rgba(0, 0, 0, 0.3);
  z-index: 12500;
  opacity: 0;
  pointer-events: none;
  padding: 14px;
  transition: opacity 180ms ease, transform 180ms ease;
}

.depth-editor.visible {
  opacity: 1;
  pointer-events: all;
  transform: translate(-50%, -50%) scale(1);
}

.depth-editor h4 {
  margin: 0 0 6px;
}

.depth-editor p {
  margin: 0 0 10px;
  color: var(--muted);
  font-size: 0.86rem;
}

.depth-editor input {
  width: 100%;
  height: 38px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--panel-alt);
  color: var(--text);
  padding: 0 10px;
  font-family: "IBM Plex Mono", monospace;
}

.depth-actions {
  display: flex;
  justify-content: flex-end;
  gap: 8px;
  margin-top: 10px;
}

.depth-error {
  position: fixed;
  left: 50%;
  top: 18px;
  transform: translateX(-50%);
  border-radius: 10px;
  border: 1px solid #de5252;
  background: color-mix(in oklab, #de5252, var(--panel) 72%);
  color: #fff;
  padding: 9px 12px;
  font-size: 0.86rem;
  z-index: 12600;
  opacity: 0;
  pointer-events: none;
}

.depth-error.visible {
  opacity: 1;
}

.depth-error.shake {
  animation: shake-x 460ms ease-in-out;
}

.download-toast {
  position: fixed;
  left: 50%;
  bottom: 18px;
  transform: translateX(-50%);
  border-radius: 10px;
  border: 1px solid #de5252;
  background: color-mix(in oklab, #de5252, var(--panel) 72%);
  color: #fff;
  padding: 9px 12px;
  font-size: 0.86rem;
  z-index: 12600;
  opacity: 0;
  pointer-events: none;
  transition: opacity 180ms ease;
}

.download-toast.visible {
  opacity: 1;
}

.guide-overlay {
  position: fixed;
  inset: 0;
  background: color-mix(in oklab, var(--bg), transparent 42%);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  z-index: 12700;
  transition: opacity 220ms ease;
}

.guide-overlay.visible {
  opacity: 1;
  pointer-events: all;
}

.guide-card {
  width: min(860px, calc(100vw - 32px));
  min-height: min(560px, calc(100vh - 36px));
  border-radius: 18px;
  border: 1px solid var(--border);
  background: color-mix(in oklab, var(--panel), transparent 4%);
  box-shadow: 0 24px 42px rgba(0, 0, 0, 0.3);
  position: relative;
  display: flex;
  flex-direction: column;
  padding: 18px;
  overflow: hidden;
}

.guide-card::before {
  content: "";
  position: absolute;
  width: 320px;
  height: 320px;
  right: -120px;
  top: -120px;
  background: radial-gradient(circle, color-mix(in oklab, var(--accent-2), transparent 75%), transparent 65%);
  pointer-events: none;
}

.guide-confetti {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
  z-index: 0;
}

.guide-close-btn {
  position: absolute;
  right: 14px;
  top: 14px;
  width: 38px;
  height: 38px;
  padding: 0;
  z-index: 3;
  pointer-events: auto;
}

.guide-body {
  padding: 8px 8px 0;
  flex: 1;
  position: relative;
  z-index: 1;
}

.guide-pill {
  display: inline-block;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: color-mix(in oklab, var(--panel-alt), transparent 15%);
  color: var(--muted);
  padding: 4px 10px;
  font-size: 0.75rem;
  margin-bottom: 12px;
}

.guide-body h3 {
  margin: 0 0 12px;
  font-size: 1.3rem;
}

.guide-progress-track {
  height: 6px;
  border-radius: 999px;
  background: color-mix(in oklab, var(--panel-alt), transparent 25%);
  overflow: hidden;
  margin-bottom: 14px;
}

.guide-progress-fill {
  height: 100%;
  width: 0;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  transition: width 260ms ease;
}

.guide-content {
  color: var(--text);
  font-size: 1rem;
  line-height: 1.6;
  animation: guide-fade 220ms ease;
}

.guide-content p {
  margin: 0 0 10px;
}

.guide-content ul {
  margin: 0;
  padding-left: 20px;
}

.guide-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.guide-note {
  border: 1px solid var(--border);
  border-radius: 10px;
  background: color-mix(in oklab, var(--panel-alt), transparent 12%);
  padding: 10px;
  font-size: 0.92rem;
}

.guide-note strong {
  display: block;
  margin-bottom: 4px;
}

.guide-flow {
  display: grid;
  grid-template-columns: 1fr;
  gap: 8px;
}

.guide-step {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 10px 12px;
  background: color-mix(in oklab, var(--panel-alt), transparent 12%);
}

.guide-step .step-head {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  border-radius: 999px;
  font-size: 0.74rem;
  font-weight: 700;
  margin-right: 8px;
  background: linear-gradient(140deg, var(--accent), var(--accent-2));
  color: #fff;
}

.guide-step strong {
  font-size: 0.95rem;
}

.guide-step p {
  margin: 8px 0 0;
  font-size: 0.92rem;
  color: var(--muted);
}

.guide-arrow {
  text-align: center;
  color: var(--muted);
  font-size: 1rem;
  line-height: 1;
}

.guide-matrix {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.guide-matrix.two {
  margin-top: 10px;
}

.guide-matrix-card {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 10px;
  background: color-mix(in oklab, var(--panel-alt), transparent 12%);
}

.guide-matrix-card h5 {
  margin: 0 0 6px;
  font-size: 0.95rem;
}

.guide-matrix-card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.guide-lane {
  display: grid;
  grid-template-columns: 1fr auto 1fr auto 1fr;
  gap: 8px;
  align-items: stretch;
  margin-bottom: 10px;
}

.guide-node {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 10px;
  background: color-mix(in oklab, var(--panel-alt), transparent 12%);
}

.guide-node span {
  display: inline-block;
  font-weight: 700;
  margin-bottom: 6px;
}

.guide-node p {
  margin: 0;
  color: var(--muted);
  font-size: 0.88rem;
}

.guide-link {
  display: grid;
  place-items: center;
  color: var(--muted);
  font-weight: 700;
}

.guide-compare {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-bottom: 10px;
}

.guide-compare-card {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 10px;
  background: color-mix(in oklab, var(--panel-alt), transparent 12%);
}

.guide-compare-card h5 {
  margin: 0 0 6px;
  font-size: 0.95rem;
}

.guide-compare-card p {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 0.9rem;
}

.guide-chipline {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.guide-chip {
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 3px 8px;
  font-size: 0.74rem;
  color: var(--text);
  background: color-mix(in oklab, var(--panel), transparent 8%);
}

.guide-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--border);
  margin-top: 14px;
  padding-top: 12px;
  position: relative;
  z-index: 1;
}

@keyframes guide-fade {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.guide-title-slide {
  min-height: 320px;
  display: grid;
  place-items: center;
  text-align: center;
  border: 1px solid var(--border);
  border-radius: 14px;
  background:
    radial-gradient(circle at 20% 20%, color-mix(in oklab, var(--accent-2), transparent 82%), transparent 45%),
    radial-gradient(circle at 80% 70%, color-mix(in oklab, var(--accent), transparent 82%), transparent 42%),
    color-mix(in oklab, var(--panel-alt), transparent 8%);
}

.guide-title-slide h4 {
  margin: 0;
  font-size: 2rem;
  letter-spacing: 0.03em;
}

.guide-title-slide p {
  margin: 10px 0 0;
  color: var(--muted);
}

.guide-mode-updated-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 14px;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 14px;
  background: linear-gradient(120deg, color-mix(in oklab, var(--accent), transparent 72%), color-mix(in oklab, var(--accent-2), transparent 72%));
  border: 1px solid color-mix(in oklab, var(--accent), transparent 45%);
  color: var(--accent);
  animation: badge-pop 400ms cubic-bezier(0.2, 0.8, 0.2, 1) both;
}

.guide-mode-updated-badge.expert {
  background: linear-gradient(120deg, color-mix(in oklab, var(--accent-2), transparent 72%), color-mix(in oklab, #b078ff, transparent 72%));
  border-color: color-mix(in oklab, var(--accent-2), transparent 45%);
  color: var(--accent-2);
}

@keyframes badge-pop {
  from { opacity: 0; transform: scale(0.85) translateY(-4px); }
  to   { opacity: 1; transform: scale(1) translateY(0); }
}

.guide-learn-cta {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 16px;
  padding: 14px 18px;
  border-radius: 12px;
  border: 1px solid color-mix(in oklab, var(--accent-2), transparent 50%);
  background: color-mix(in oklab, var(--accent-2), transparent 88%);
  color: var(--text);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  transition: transform 120ms ease, border-color 120ms ease;
}

.guide-learn-cta:hover {
  transform: translateY(-1px);
  border-color: var(--accent-2);
}

.guide-learn-cta i {
  color: var(--accent-2);
  font-size: 1.1rem;
  flex-shrink: 0;
}

/* Guide slide lesson link strip */
.guide-lesson-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 14px;
  padding-top: 10px;
  border-top: 1px solid var(--border);
}

.guide-lesson-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 12px;
  border-radius: 999px;
  font-size: 0.78rem;
  font-weight: 500;
  border: 1px solid color-mix(in oklab, var(--accent), transparent 55%);
  background: color-mix(in oklab, var(--accent), transparent 88%);
  color: var(--accent);
  text-decoration: none;
  transition: background 120ms ease, border-color 120ms ease;
}

.guide-lesson-link:hover {
  background: color-mix(in oklab, var(--accent), transparent 78%);
  border-color: var(--accent);
}

.confetti-piece {
  position: absolute;
  width: 8px;
  height: 14px;
  border-radius: 2px;
  opacity: 0.9;
  animation: confetti-fall 3200ms linear forwards;
}

@keyframes confetti-fall {
  0% {
    transform: translateY(-16px) rotate(0deg);
    opacity: 1;
  }
  100% {
    transform: translateY(440px) rotate(540deg);
    opacity: 0;
  }
}

.guide-nav .icon-btn {
  width: 42px;
  height: 42px;
}

@keyframes shake-x {
  0% { transform: translateX(-50%) translateX(0); }
  12% { transform: translateX(-50%) translateX(-12px); }
  24% { transform: translateX(-50%) translateX(12px); }
  36% { transform: translateX(-50%) translateX(-10px); }
  48% { transform: translateX(-50%) translateX(10px); }
  60% { transform: translateX(-50%) translateX(-8px); }
  72% { transform: translateX(-50%) translateX(8px); }
  84% { transform: translateX(-50%) translateX(-5px); }
  100% { transform: translateX(-50%) translateX(0); }
}

/* Mode Switcher */
.mode-switcher {
  display: flex;
  background: var(--panel-alt);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 3px;
  gap: 2px;
  /* Constrain to only its own content. Does not stretch into nav */
  align-self: center;
  width: fit-content;
  flex-shrink: 0;
}

.mode-btn {
  padding: 6px 16px;
  border-radius: 9px;
  border: none;
  background: transparent;
  color: var(--muted);
  font-family: inherit;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 200ms ease, color 200ms ease, box-shadow 200ms ease;
  white-space: nowrap;
  position: relative;
}

.mode-btn:hover {
  color: var(--text);
  background: color-mix(in oklab, var(--panel), transparent 20%);
}

/* Basic */
.mode-btn[data-mode="basic"].active {
  background: linear-gradient(125deg, #1aab6d, #0ecf8a);
  color: #fff;
  box-shadow: 0 2px 10px color-mix(in oklab, #0ecf8a, transparent 48%);
}

/* Advanced */
.mode-btn[data-mode="advanced"].active {
  background: linear-gradient(125deg, #e8620a, #f59c1a);
  color: #fff;
  box-shadow: 0 2px 10px color-mix(in oklab, #f59c1a, transparent 48%);
}

/* Expert */
.mode-btn[data-mode="expert"].active {
  background: linear-gradient(125deg, #7c1d1d, #b83232);
  color: #fff;
  box-shadow: 0 2px 10px color-mix(in oklab, #b83232, transparent 48%);
}

/* Advanced / Expert Gate Library */
.adv-gate-library {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.adv-controls {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 12px;
}

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

.qubit-count-btn {
  flex: 1;
  height: 34px;
  border-radius: 9px;
  border: 1px solid var(--border);
  background: var(--panel-alt);
  color: var(--muted);
  font-family: "IBM Plex Mono", monospace;
  font-size: 0.88rem;
  font-weight: 700;
  cursor: pointer;
  transition: background 140ms ease, color 140ms ease, border-color 140ms ease;
}

.qubit-count-btn:hover {
  color: var(--text);
  border-color: var(--accent-2);
}

.qubit-count-btn.active {
  background: linear-gradient(120deg, var(--accent), var(--accent-2));
  color: #fff;
  border-color: transparent;
}

/* Add/Remove Qubit Buttons (Expert Mode) */
.qubit-control-row {
  display: flex;
  gap: 6px;
  align-items: center;
}

.qubit-control-row .qubit-info {
  font-size: 0.75rem;
  color: var(--muted);
  font-family: "IBM Plex Mono", monospace;
  margin-right: 4px;
  flex: 1;
}

.qubit-add-btn, .qubit-remove-btn {
  height: 34px;
  width: 34px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--panel-alt);
  color: var(--muted);
  font-weight: 700;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all 140ms ease;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.qubit-add-btn:hover:not(:disabled) {
  color: var(--accent);
  border-color: var(--accent);
  background: color-mix(in oklab, var(--accent), transparent 85%);
}

.qubit-remove-btn:hover:not(:disabled) {
  color: #e34d4d;
  border-color: #e34d4d;
  background: color-mix(in oklab, #e34d4d, transparent 85%);
}

.qubit-add-btn:disabled, .qubit-remove-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.qubit-error {
  font-size: 0.75rem;
  color: #e34d4d;
  margin-top: 4px;
  transition: opacity 200ms ease;
  opacity: 0;
  font-family: "IBM Plex Mono", monospace;
}

.qubit-error.show {
  opacity: 1;
}

/* Multi-qubit circuit canvas */
.adv-circuit-wrap {
  min-height: 320px;
  overflow-x: auto;
  overflow-y: hidden;
  position: relative;
  z-index: 0;
}

.qubit-preset-dropdown {
  position: absolute;
  width: 44px;
  height: 44px;
  font-size: 0.76rem;
  font-weight: 600;
  font-family: inherit;
  padding: 0 10px 0 10px;
  border-radius: 14px;
  border: 1.5px solid var(--border);
  background: var(--panel);
  color: var(--text);
  cursor: pointer;
  z-index: 2;
  box-shadow: 0 1px 5px rgba(0,0,0,0.09);
  transition: border-color 120ms ease, box-shadow 120ms ease;
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6' viewBox='0 0 10 6'%3E%3Cpath d='M0 0l5 6 5-6z' fill='%23888888'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 5px center;
}
.qubit-preset-dropdown:hover {
  border-color: var(--accent);
}
.qubit-preset-dropdown:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 2px color-mix(in oklab, var(--accent), transparent 72%);
  outline: none;
}

.adv-pending-prompt {
  display: none;
  padding: 7px 12px;
  border-radius: 8px;
  background: color-mix(in oklab, var(--accent), transparent 82%);
  border: 1px solid var(--accent);
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 500;
  margin-bottom: 6px;
}
.adv-pending-prompt.visible {
  display: block;
}
.gate-card.gate-pending-active {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  background: color-mix(in oklab, var(--accent), transparent 88%);
}


/* Basis state probability bars */
.adv-prob-bars {
  display: flex;
  flex-direction: column;
  gap: 7px;
  margin-top: 4px;
}

.adv-prob-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.adv-prob-label {
  font-family: "IBM Plex Mono", monospace;
  font-size: 0.75rem;
  color: var(--text);
  width: 40px;
  flex-shrink: 0;
  text-align: right;
}

.adv-prob-track {
  flex: 1;
  height: 14px;
  background: color-mix(in oklab, var(--panel), black 8%);
  border-radius: 99px;
  overflow: hidden;
}

.adv-prob-fill {
  height: 100%;
  border-radius: 99px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  transition: width 480ms cubic-bezier(0.2, 0.8, 0.2, 1);
  min-width: 2px;
}

.adv-prob-pct {
  font-family: "IBM Plex Mono", monospace;
  font-size: 0.72rem;
  color: var(--muted);
  width: 38px;
  flex-shrink: 0;
  text-align: left;
}

/* Per-qubit Bloch sphere row */
.adv-bloch-row {
  display: grid;
  gap: 10px;
  grid-auto-flow: dense;
  grid-auto-columns: 1fr;
}

.adv-bloch-row > * {
  overflow: hidden;
}

.adv-bloch-cell {
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.adv-bloch-label {
  font-size: 0.72rem;
  color: var(--muted);
  text-align: center;
  margin-bottom: 4px;
  font-family: "IBM Plex Mono", monospace;
  font-weight: 500;
}

.adv-bloch-canvas-wrap {
  width: 100%;
  height: 160px;
  max-height: 180px;
  border-radius: 10px;
  border: 1px solid var(--border);
  overflow: hidden;
  background: var(--panel-alt);
  position: relative;
}

.adv-bloch-canvas-wrap.entangled {
  border-color: color-mix(in oklab, var(--accent-2), transparent 45%);
  opacity: 0.65;
}

/* Entanglement badge */
.entanglement-badge {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid color-mix(in oklab, #b078ff, transparent 50%);
  background: color-mix(in oklab, #b078ff, transparent 88%);
  font-size: 0.85rem;
  line-height: 1.5;
  color: var(--text);
  animation: pattern-pop 280ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

/* Expert phase display */
.exp-phase-display {
  display: flex;
  flex-direction: column;
  gap: 5px;
  margin-top: 4px;
}

.exp-phase-row {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.75rem;
  font-family: "IBM Plex Mono", monospace;
}

.exp-phase-label {
  width: 40px;
  text-align: right;
  color: var(--text);
  flex-shrink: 0;
}

.exp-phase-dial {
  width: 28px;
  height: 28px;
  flex-shrink: 0;
}

.exp-phase-val {
  color: var(--muted);
}

@media (max-width: 1180px) {
  .layout-advanced {
    grid-template-columns: 1fr;
  }
  
  .adv-bloch-row {
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  }
}

@media (max-width: 900px) {
  .adv-bloch-row {
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
  }
  
  .adv-bloch-cell {
    max-height: 200px;
  }
}

@media (max-width: 640px) {
  .adv-bloch-row {
    grid-template-columns: 1fr;
    gap: 10px;
  }
  
  .adv-circuit-wrap {
    min-height: 280px;
  }
}

.contact-fab {
  position: fixed;
  bottom: 22px;
  right: 22px;
  width: 48px;
  height: 48px;
  border-radius: 999px;
  border: 1px solid color-mix(in oklab, var(--accent-2), transparent 40%);
  background: linear-gradient(140deg, var(--accent), var(--accent-2));
  color: #fff;
  font-size: 1.05rem;
  display: grid;
  place-items: center;
  cursor: pointer;
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.28), 0 0 0 0 color-mix(in oklab, var(--accent-2), transparent 60%);
  transition: transform 140ms ease, box-shadow 180ms ease;
  z-index: 11500;
}

.contact-fab:hover {
  transform: translateY(-2px) scale(1.05);
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.32), 0 0 0 6px color-mix(in oklab, var(--accent-2), transparent 72%);
}

/* Contact Modal */
.contact-modal {
  position: fixed;
  inset: 0;
  background: color-mix(in oklab, var(--bg), transparent 42%);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  z-index: 12700;
  transition: opacity 220ms ease;
}

.contact-modal.visible {
  opacity: 1;
  pointer-events: all;
}

.contact-card {
  width: min(420px, calc(100vw - 32px));
  border-radius: 18px;
  border: 1px solid var(--border);
  background: color-mix(in oklab, var(--panel), transparent 4%);
  box-shadow: 0 24px 42px rgba(0, 0, 0, 0.3);
  padding: 24px;
  position: relative;
  overflow: hidden;
}

.contact-card::before {
  content: "";
  position: absolute;
  width: 260px;
  height: 260px;
  right: -100px;
  top: -100px;
  background: radial-gradient(circle, color-mix(in oklab, var(--accent-2), transparent 78%), transparent 65%);
  pointer-events: none;
}

.contact-header {
  text-align: center;
  margin-bottom: 20px;
  position: relative;
  z-index: 1;
}

.contact-avatar {
  width: 52px;
  height: 52px;
  border-radius: 14px;
  background: linear-gradient(140deg, var(--accent), var(--accent-2));
  display: grid;
  place-items: center;
  margin: 0 auto 12px;
  overflow: hidden;
}

.contact-avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.contact-header h3 {
  margin: 0 0 6px;
  font-size: 1.2rem;
}

.contact-header p {
  margin: 0;
  color: var(--muted);
  font-size: 0.88rem;
}

.contact-links {
  display: flex;
  flex-direction: column;
  gap: 10px;
  position: relative;
  z-index: 1;
}

.contact-link {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--panel-alt);
  color: var(--text);
  text-decoration: none;
  transition: transform 120ms ease, border-color 120ms ease, box-shadow 120ms ease;
}

.contact-link:hover {
  transform: translateY(-1px);
  border-color: var(--accent-2);
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.14);
}

.contact-link > i:first-child {
  font-size: 1.1rem;
  color: var(--accent-2);
  width: 20px;
  text-align: center;
}

.contact-link div {
  flex: 1;
}

.contact-link strong {
  display: block;
  font-size: 0.9rem;
}

.contact-link span {
  font-size: 0.8rem;
  color: var(--muted);
}

.contact-link-arrow {
  font-size: 0.75rem;
  color: var(--muted);
}

/* Clear Circuit Confirm Popover */
.confirm-popover {
  position: fixed;
  width: 264px;
  border-radius: 14px;
  border: 1px solid var(--border);
  background: var(--panel);
  box-shadow: 0 18px 36px rgba(0, 0, 0, 0.3);
  padding: 16px;
  z-index: 12700;
  opacity: 0;
  transform: scale(0.94);
  pointer-events: none;
  transition: opacity 140ms ease, transform 140ms ease;
}

.confirm-popover.visible {
  opacity: 1;
  transform: scale(1);
  pointer-events: all;
}

.confirm-popover-header {
  display: flex;
  align-items: center;
  gap: 9px;
  font-weight: 700;
  font-size: 0.95rem;
  margin-bottom: 6px;
}

.confirm-popover-header i {
  color: #f06262;
  font-size: 0.95rem;
}

.confirm-popover p {
  margin: 0 0 14px;
  color: var(--muted);
  font-size: 0.82rem;
  line-height: 1.5;
}

.confirm-checkbox {
  display: flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 16px;
  font-size: 0.82rem;
  color: var(--muted);
  cursor: pointer;
  user-select: none;
}

.confirm-checkbox input {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.confirm-checkbox-box {
  width: 18px;
  height: 18px;
  border-radius: 5px;
  border: 2px solid var(--border);
  background: var(--panel-alt);
  display: grid;
  place-items: center;
  flex-shrink: 0;
  transition: border-color 150ms ease, background 150ms ease;
}

.confirm-checkbox input:checked + .confirm-checkbox-box {
  border-color: var(--accent);
  background: color-mix(in oklab, var(--accent), transparent 78%);
}

.confirm-checkbox input:checked + .confirm-checkbox-box::after {
  content: "";
  width: 8px;
  height: 5px;
  border-left: 2px solid var(--accent);
  border-bottom: 2px solid var(--accent);
  transform: rotate(-45deg) translateY(-1px);
  display: block;
}

.confirm-actions {
  display: flex;
  gap: 10px;
}

.confirm-danger-btn {
  color: #fff;
  background: #e14f4f;
  border-color: color-mix(in oklab, #e14f4f, #ffffff 15%);
}

.confirm-danger-btn:hover {
  filter: brightness(1.08);
}

/* Info Buttons */
.info-btn {
  display: inline-grid;
  place-items: center;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  margin-left: 4px;
  color: var(--muted);
  font-size: 0.8rem;
  vertical-align: middle;
  transition: color 120ms ease, transform 120ms ease;
  line-height: 1;
}

.info-btn:hover {
  color: var(--accent-2);
  transform: scale(1.15);
}

.info-btn-sm {
  font-size: 0.7rem;
}

.info-tooltip {
  max-width: 220px;
  width: max-content;
  white-space: normal;
  word-break: break-word;
  font-weight: 400;
  line-height: 1.5;
  padding: 10px 12px;
  font-size: 0.78rem;
  border-radius: 12px;
  box-shadow: 0 12px 24px rgba(0, 0, 0, 0.22);
  transform: none;
  pointer-events: none;
}

/* Onboarding Tour */
.tour-overlay {
  position: fixed;
  inset: 0;
  z-index: 13000;
  pointer-events: none;
}

.tour-spotlight {
  position: fixed;
  border-radius: 14px;
  box-shadow: 0 0 0 9999px color-mix(in oklab, var(--bg), transparent 30%);
  transition: all 340ms cubic-bezier(0.4, 0, 0.2, 1);
  pointer-events: none;
  z-index: 13001;
}

.tour-card {
  position: fixed;
  width: min(320px, calc(100vw - 32px));
  border-radius: 16px;
  border: 1px solid var(--border);
  background: color-mix(in oklab, var(--panel), transparent 3%);
  box-shadow: 0 18px 36px rgba(0, 0, 0, 0.32);
  padding: 16px;
  z-index: 13002;
  pointer-events: all;
  transition: all 340ms cubic-bezier(0.4, 0, 0.2, 1);
  animation: tour-pop 260ms ease;
}

@keyframes tour-pop {
  from { opacity: 0; transform: scale(0.94) translateY(6px); }
  to   { opacity: 1; transform: scale(1) translateY(0); }
}

.tour-step-pill {
  display: inline-block;
  border-radius: 999px;
  background: linear-gradient(120deg, var(--accent), var(--accent-2));
  color: #fff;
  font-size: 0.7rem;
  font-weight: 700;
  padding: 3px 10px;
  margin-bottom: 8px;
}

.tour-card h4 {
  margin: 0 0 6px;
  font-size: 1rem;
}

.tour-card p {
  margin: 0 0 14px;
  color: var(--muted);
  font-size: 0.88rem;
  line-height: 1.55;
}

.tour-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}

.tour-dots {
  display: flex;
  gap: 5px;
}

.tour-dot {
  width: 6px;
  height: 6px;
  border-radius: 999px;
  background: var(--border);
  transition: background 200ms ease, width 200ms ease;
}

.tour-dot.active {
  background: var(--accent-2);
  width: 16px;
}

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

.tour-skip {
  font-size: 0.8rem;
  color: var(--muted);
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px 6px;
  font-family: inherit;
  transition: color 120ms ease;
}

.tour-skip:hover {
  color: var(--text);
}

@media (max-width: 1180px) {
  .layout {
    grid-template-columns: 1fr;
    overflow-y: auto;
    height: auto;
  }

  .left-panel,
  .center-panel,
  .right-panel {
    overflow-y: visible;
    min-height: auto;
  }

  .circuit-wrap {
    min-height: 300px;
    flex: none;
  }

  .left-panel {
    order: 1;
  }

  .center-panel {
    order: 2;
  }

  .right-panel {
    order: 3;
  }
}

@media (max-width: 900px) {
  .topbar {
    flex-wrap: wrap;
    gap: 10px;
    align-items: flex-start;
  }

  .top-actions {
    width: 100%;
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 8px;
    justify-content: stretch;
  }

  .top-actions .btn {
    width: 100%;
    min-height: 38px;
    padding: 8px 10px;
  }

  .top-actions .icon-btn {
    width: 100%;
    height: 38px;
  }

  #undoBtn { order: 1; }
  #redoBtn { order: 2; }
  #guideBtn { order: 3; }
  #themeBtn { order: 4; }
  #exportBtn { order: 5; }
  #restoreBtn { order: 6; }

  .gate-library {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

  .left-controls {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
  }

  .control-label,
  .preset-select {
    grid-column: 1 / -1;
  }
}

@media (max-width: 640px) {
  .layout {
    padding: 8px;
    gap: 8px;
  }

  .panel {
    border-radius: 12px;
  }

  .gate-library {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .circuit-wrap {
    min-height: 270px;
  }

  .qubit-badge {
    left: 8px;
    min-width: 38px;
    height: 38px;
    font-size: 0.82rem;
  }

  .guide-grid {
    grid-template-columns: 1fr;
  }

  .guide-matrix,
  .guide-compare {
    grid-template-columns: 1fr;
  }

  .guide-lane {
    grid-template-columns: 1fr;
  }

  .guide-link {
    transform: rotate(90deg);
  }

  .stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
    padding: 8px;
  }

  .stat-divider {
    display: none;
  }

  .stat-item {
    border: 1px solid var(--border);
    border-radius: 8px;
    background: color-mix(in oklab, var(--panel), transparent 10%);
    padding: 6px 8px;
    font-size: 0.82rem;
  }

  .depth-edit-btn {
    width: 22px;
    height: 22px;
    margin-left: auto;
  }

  .top-actions {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .top-actions .btn {
    font-size: 0.82rem;
  }
}

@media (max-width: 460px) {
  .stats {
    grid-template-columns: 1fr;
  }

  .top-actions {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .top-actions .btn {
    min-height: 36px;
    font-size: 0.8rem;
    padding: 7px 8px;
  }
}

/* Advanced/Expert popup overlays */
.adv-popup-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(4px);
  z-index: 10000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.adv-popup {
  background: var(--panel);
  border-radius: 16px;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
  max-width: 90vw;
  max-height: 90vh;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.adv-popup-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 24px;
  border-bottom: 1px solid var(--border);
  background: var(--panel-alt);
}

.adv-popup-header h3 {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text);
}

.adv-popup-close {
  background: none;
  border: none;
  font-size: 1.25rem;
  color: var(--muted);
  cursor: pointer;
  padding: 4px;
  border-radius: 6px;
  transition: all 0.2s ease;
}

.adv-popup-close:hover {
  background: var(--border);
  color: var(--text);
}

.adv-popup-content {
  padding: 24px;
  overflow-y: auto;
  flex: 1;
}

/* Probability popup styles */
.adv-prob-row {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
  padding: 8px 12px;
  background: var(--panel-alt);
  border-radius: 8px;
}

.adv-prob-label {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.9rem;
  font-weight: 500;
  min-width: 60px;
  text-align: center;
}

.adv-prob-track {
  flex: 1;
  height: 20px;
  background: var(--border);
  border-radius: 10px;
  overflow: hidden;
}

.adv-prob-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  border-radius: 10px;
  transition: width 0.3s ease;
}

.adv-prob-pct {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--muted);
  min-width: 45px;
  text-align: right;
}

/* Bloch sphere popup styles */
.adv-bloch-popup-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
}

.adv-popup-bloch-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  padding: 16px;
  background: var(--panel-alt);
  border-radius: 12px;
}

.adv-popup-bloch-label {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text);
}

.adv-popup-bloch-canvas {
  width: 200px;
  height: 200px;
}

/* Expandable button styles */
.expand-btn {
  width: 100%;
  padding: 12px 16px;
  background: var(--accent);
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
}

.expand-btn:hover {
  background: var(--accent-2);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

/* Embed mode (iframe lesson embeds) */
body.embed .topbar,
body.embed .site-footer,
body.embed .left-panel,
body.embed .right-panel,
body.embed .contact-fab {
  display: none !important;
}

body.embed .layout {
  grid-template-columns: 1fr !important;
  min-height: 0 !important;
  height: 100%;
  padding: 6px;
  gap: 6px;
}

body.embed .app {
  min-height: 100vh;
}

body.embed .center-panel {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

/* Compact gate bar injected in embed mode */
.embed-gate-bar {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 8px 10px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  flex-shrink: 0;
}

.embed-bar-gates {
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
}

.embed-bar-controls {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: 2px;
}

.embed-preset {
  flex: 1;
  min-width: 80px;
  height: 30px !important;
  font-size: 0.78rem;
}

.embed-alg-preset {
  width: auto;
  max-width: 140px;
  height: 30px !important;
  font-size: 0.78rem;
}

.embed-gate-chip {
  padding: 4px 11px;
  border-radius: 8px;
  border: 2px solid var(--gate-color, var(--border));
  background: var(--panel-alt);
  color: var(--text);
  font-weight: 700;
  font-size: 0.82rem;
  font-family: "IBM Plex Mono", monospace;
  cursor: pointer;
  transition: transform 100ms ease, filter 100ms ease, box-shadow 100ms ease;
  line-height: 1.4;
}

.embed-gate-chip:hover {
  transform: translateY(-1px);
  filter: brightness(1.12);
  box-shadow: 0 0 8px color-mix(in oklab, var(--gate-color, var(--border)), transparent 55%);
}

body.embed .circuit-wrap {
  flex: 1;
  min-height: 140px;
}

/* Responsive popup adjustments */
@media (max-width: 768px) {
  .adv-popup-overlay {
    padding: 10px;
  }
  
  .adv-popup {
    max-width: 95vw;
    max-height: 95vh;
  }
  
  .adv-popup-header {
    padding: 16px 20px;
  }
  
  .adv-popup-header h3 {
    font-size: 1.1rem;
  }
  
  .adv-popup-content {
    padding: 20px;
  }
  
  .adv-bloch-popup-content {
    grid-template-columns: 1fr;
  }
  
  .adv-popup-bloch-canvas {
    width: 180px;
    height: 180px;
  }
}