/* active/cylinder-cone/style.css - The One Academy TH 3D Geometry Lab */

:root {
  --mod-bg: #f8fafc;
  --mod-surface: #ffffff;
  --mod-surface-alt: #f1f5f9;
  --mod-text: #1e293b;
  --mod-text-muted: #64748b;
  --mod-heading: #0f172a;
  --mod-border: #cbd5e1;
  --mod-primary: #4338ca;
  --mod-primary-hover: #3730a3;
  --mod-accent: #d97706;
  --mod-cyan: #0284c7;
  --mod-purple: #6366f1;
  --mod-gold: #b4860b;
  --mod-green: #166534;
  --mod-orange: #c2410c;
  --mod-shadow: 0 10px 30px rgba(15, 23, 42, 0.06);
}

:root[data-theme="dark"] {
  --mod-bg: #0a0912;
  --mod-surface: #141124;
  --mod-surface-alt: #1e1b32;
  --mod-text: #eceaf8;
  --mod-text-muted: #a8a3c4;
  --mod-heading: #f8fafc;
  --mod-border: rgba(184, 176, 255, 0.18);
  --mod-primary: #6366f1;
  --mod-primary-hover: #818cf8;
  --mod-accent: #f1c96b;
  --mod-cyan: #38bdf8;
  --mod-purple: #818cf8;
  --mod-gold: #facc15;
  --mod-green: #4ade80;
  --mod-orange: #fb923c;
  --mod-shadow: 0 12px 32px rgba(0, 0, 0, 0.45);
}

body {
  background: var(--mod-bg);
  color: var(--mod-text);
}

.active-module-page,
.active-module-page *,
.active-module-page *::before,
.active-module-page *::after {
  box-sizing: border-box;
}

.active-module-page {
  padding: 24px 0 64px;
}

/* Breadcrumb */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 20px;
  font-size: 0.92rem;
  color: var(--mod-text-muted);
}

.breadcrumb a {
  color: var(--mod-text-muted);
  text-decoration: none;
  font-weight: 600;
}

.breadcrumb a:hover {
  color: var(--mod-primary);
  text-decoration: underline;
}

/* Hero Section */
.module-hero {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
  padding: 28px 32px;
  background: var(--mod-surface);
  border: 1px solid var(--mod-border);
  border-radius: 24px;
  box-shadow: var(--mod-shadow);
  margin-bottom: 28px;
}

.hero-content h1 {
  font-size: clamp(1.8rem, 4vw, 2.5rem);
  color: var(--mod-heading);
  margin: 8px 0;
  line-height: 1.15;
}

.hero-content p {
  color: var(--mod-text-muted);
  margin: 0;
  font-size: 1.05rem;
}

.pill {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(99, 102, 241, 0.12);
  color: var(--mod-primary);
  font-weight: 800;
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* Shape Switcher Tabs */
.shape-switcher-row {
  display: flex;
  gap: 10px;
  background: var(--mod-surface-alt);
  padding: 6px;
  border-radius: 18px;
  border: 1px solid var(--mod-border);
}

.shape-tab-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  border: 0;
  border-radius: 14px;
  background: transparent;
  color: var(--mod-text-muted);
  font-weight: 800;
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.shape-tab-btn:hover {
  color: var(--mod-heading);
}

.shape-tab-btn.active {
  background: var(--mod-primary);
  color: #ffffff !important;
  box-shadow: 0 4px 14px rgba(99, 102, 241, 0.35);
}

.shape-icon {
  font-size: 1.25rem;
}

/* Workspace Grid (Desktop 2-Column) */
.workspace-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.08fr) minmax(340px, 0.92fr);
  gap: 24px;
  align-items: start;
}

/* Viewport Card (Left Panel) */
.viewport-card {
  background: var(--mod-surface);
  border: 1px solid var(--mod-border);
  border-radius: 24px;
  padding: 20px;
  box-shadow: var(--mod-shadow);
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.viewport-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 16px;
}

.viewport-title {
  font-weight: 800;
  font-size: 1.15rem;
  color: var(--mod-heading);
}

.viewport-badges {
  display: flex;
  gap: 8px;
}

.badge {
  padding: 4px 10px;
  border-radius: 8px;
  font-size: 0.82rem;
  font-weight: 800;
}

.badge-cyan { background: rgba(2, 132, 199, 0.15); color: var(--mod-cyan); }
.badge-purple { background: rgba(99, 102, 241, 0.15); color: var(--mod-purple); }

/* Canvas Container */
.canvas-container {
  position: relative;
  width: 100%;
  height: 480px;
  background: var(--mod-surface-alt);
  border: 1px solid var(--mod-border);
  border-radius: 18px;
  overflow: hidden;
  isolation: isolate;
}

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

.canvas-controls-bar {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
}

.tool-btn {
  min-width: 0;
  background: rgba(15, 23, 42, 0.92);
  color: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 12px;
  padding: 10px 12px;
  font-size: 0.9rem;
  font-weight: 800;
  cursor: pointer;
  backdrop-filter: blur(8px);
  transition: all 0.2s ease;
}

.tool-btn:hover {
  background: rgba(15, 23, 42, 0.95);
  transform: translateY(-1px);
}

.viewport-hint {
  margin: 0;
  font-size: 0.88rem;
  color: var(--mod-text-muted);
  text-align: center;
}

.mobile-label-summary {
  display: none;
}

.viewport-detail-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.45fr) minmax(210px, .75fr);
  gap: 14px;
  align-items: stretch;
}

.sliders-card-inline {
  margin: 0;
}

/* Control Panel (Right Panel) */
.control-panel-card {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

/* Stepper Bar */
.stepper-bar {
  background: var(--mod-surface);
  border: 1px solid var(--mod-border);
  border-radius: 18px;
  padding: 14px;
  box-shadow: var(--mod-shadow);
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.stepper-bar-near-model {
  margin-top: 10px;
  margin-bottom: 2px;
}

.step-controls-four {
  display: grid;
  grid-template-columns: 58px 58px minmax(160px, 1fr) minmax(128px, 0.9fr);
  gap: 10px;
  align-items: center;
}

.step-badge {
  background: var(--mod-primary);
  color: #ffffff;
  font-weight: 900;
  padding: 8px 14px;
  border-radius: 999px;
  font-size: 0.9rem;
  white-space: nowrap;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.step-badge-button {
  border: 0;
  cursor: pointer;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease;
  box-shadow: 0 10px 20px rgba(79, 70, 229, 0.24);
}

.step-badge-button:hover:not(:disabled) {
  transform: translateY(-1px);
  background: var(--mod-primary-hover);
}

.step-badge-button:disabled {
  opacity: .7;
  cursor: not-allowed;
}

.step-progress-track {
  flex: 1;
  height: 8px;
  background: var(--mod-surface-alt);
  border-radius: 999px;
  overflow: hidden;
}

.step-progress-fill {
  height: 100%;
  width: 25%;
  background: linear-gradient(90deg, #6366f1, #0284c7);
  transition: width 0.3s ease;
}

/* Step Info Block */
.step-info-block {
  background: var(--mod-surface);
  border: 1px solid var(--mod-border);
  border-left: 5px solid var(--mod-primary);
  border-radius: 18px;
  padding: 20px;
  box-shadow: var(--mod-shadow);
}

.step-info-block h2 {
  margin: 0 0 8px 0;
  font-size: 1.3rem;
  color: var(--mod-heading);
}

.step-info-block p {
  margin: 0;
  color: var(--mod-text-muted);
  line-height: 1.6;
}

/* Sliders Card */
.sliders-card {
  background: var(--mod-surface);
  border: 1px solid var(--mod-border);
  border-radius: 18px;
  padding: 20px;
  box-shadow: var(--mod-shadow);
}

.sliders-card h3,
.formulas-card h3 {
  margin: 0 0 16px 0;
  font-size: 1.05rem;
  color: var(--mod-heading);
}

.slider-field {
  margin-bottom: 16px;
}

.slider-field:last-child {
  margin-bottom: 0;
}

.slider-label-row {
  display: flex;
  justify-content: space-between;
  margin-bottom: 6px;
  font-weight: 700;
}

.slider-val {
  color: var(--mod-primary);
  font-weight: 900;
}

input[type="range"] {
  width: 100%;
  height: 8px;
  border-radius: 999px;
  background: var(--mod-surface-alt);
  accent-color: var(--mod-primary);
  cursor: pointer;
}

.slant-display-row {
  margin-top: 12px;
  padding: 10px 14px;
  background: var(--mod-surface-alt);
  border: 1px solid var(--mod-border);
  border-radius: 12px;
  display: flex;
  justify-content: space-between;
  font-weight: 800;
  font-size: 0.95rem;
}

.slant-val {
  color: var(--mod-orange);
}

/* Formulas Card */
.formulas-card {
  background: var(--mod-surface);
  border: 1px solid var(--mod-border);
  border-radius: 18px;
  padding: 20px;
  box-shadow: var(--mod-shadow);
}

.formula-grid {
  display: grid;
  gap: 12px;
}

.formula-row {
  padding: 12px 14px;
  background: var(--mod-surface-alt);
  border: 1px solid var(--mod-border);
  border-radius: 12px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.formula-row.highlight {
  border-left: 4px solid var(--mod-accent);
  background: rgba(245, 158, 11, 0.08);
}

.formula-title {
  font-size: 0.85rem;
  font-weight: 800;
  color: var(--mod-primary);
}

.formula-expr {
  font-weight: 700;
  color: var(--mod-heading);
  font-size: 1rem;
}

.formula-calc {
  font-size: 0.92rem;
  font-weight: 800;
  color: var(--mod-accent);
}

/* Step Controls */
.btn-auto-inline {
  width: 100%;
  min-width: 0;
}

.btn-step-square {
  width: 100%;
  min-width: 0;
  padding-inline: 0;
}

.step-badge-inline {
  width: 100%;
  min-width: 0;
}

.btn-step {
  flex: 1;
  padding: 12px 16px;
  border-radius: 14px;
  border: 1px solid var(--mod-border);
  font-weight: 800;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all 0.2s ease;
  min-height: 48px;
}

.btn-prev {
  background: var(--mod-surface);
  color: var(--mod-text);
}

.btn-prev:hover:not(:disabled) {
  background: var(--mod-surface-alt);
}

.btn-next {
  background: var(--mod-primary);
  color: #ffffff !important;
  border-color: var(--mod-primary);
}

.btn-next:hover:not(:disabled) {
  background: var(--mod-primary-hover);
}

.btn-auto {
  background: var(--mod-surface-alt);
  color: var(--mod-heading);
}

.btn-auto:hover:not(:disabled) {
  background: rgba(99, 102, 241, 0.15);
}

.btn-step:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

/* Responsive Rules (Mobile 430px) */
@media (max-width: 980px) {
  .workspace-grid {
    grid-template-columns: 1fr;
  }

  .canvas-container {
    height: 360px;
  }

  .module-hero {
    flex-direction: column;
    align-items: flex-start;
    padding: 20px;
  }

  .shape-switcher-row {
    width: 100%;
  }

  .shape-tab-btn {
    flex: 1;
    justify-content: center;
  }

  .viewport-detail-grid {
    grid-template-columns: minmax(0, 1.35fr) minmax(190px, .65fr);
  }
}

@media (max-width: 640px) {
  .active-module-page {
    padding-top: 8px;
    padding-bottom: 28px;
  }

  .breadcrumb {
    display: none;
  }

  .module-hero {
    padding: 14px;
    gap: 12px;
    border-radius: 18px;
    margin-bottom: 16px;
  }

  .hero-content h1 {
    font-size: clamp(1.45rem, 7vw, 1.9rem);
    line-height: 1.08;
    margin: 6px 0;
  }

  .hero-content p {
    font-size: 0.95rem;
    line-height: 1.45;
  }

  .pill {
    padding: 4px 10px;
    font-size: 0.72rem;
  }

  .shape-switcher-row {
    width: 100%;
    padding: 5px;
    gap: 6px;
    border-radius: 14px;
  }

  .shape-tab-btn {
    flex: 1;
    justify-content: center;
    padding: 10px 12px;
    font-size: 0.92rem;
    border-radius: 12px;
  }

  .shape-icon {
    font-size: 1rem;
  }

  .workspace-grid {
    gap: 16px;
  }

  .viewport-card,
  .sliders-card,
  .formulas-card,
  .step-info-block,
  .stepper-bar,
  .reference-diagram-card,
  .formula-derivation-card {
    padding: 10px;
    border-radius: 16px;
  }

  .viewport-card {
    gap: 10px;
  }

  .viewport-header {
    margin-bottom: 8px;
    gap: 10px;
  }

  .viewport-title {
    font-size: 1rem;
  }

  .viewport-badges {
    flex-wrap: wrap;
    gap: 6px;
  }

  .badge {
    font-size: 0.75rem;
    padding: 4px 8px;
  }

  .canvas-container {
    height: 200px;
    border-radius: 14px;
  }

  .canvas-overlay-labels {
    display: none;
  }

  .mobile-label-summary:not(:empty) {
    display: grid;
    gap: 6px;
    padding: 8px;
    border: 1px solid var(--mod-border);
    border-radius: 12px;
    background: var(--mod-surface-alt);
  }

  .mobile-label-item {
    padding: 7px 9px;
    border-radius: 9px;
    font-size: .76rem;
    font-weight: 800;
    line-height: 1.32;
    text-align: center;
  }

  .mobile-label-item.tag-gold { background: rgba(245,158,11,.9); color: #0f172a; }
  .mobile-label-item.tag-purple { background: rgba(99,102,241,.92); color: #fff; }
  .mobile-label-item.tag-cyan { background: rgba(2,132,199,.92); color: #fff; }
  .mobile-label-item.tag-orange { background: rgba(249,115,22,.92); color: #fff; }

  .canvas-controls-bar {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 6px;
  }

  .tool-btn {
    padding: 8px 5px;
    border-radius: 10px;
    font-size: clamp(.68rem, 2.8vw, .8rem);
    line-height: 1.22;
  }

  .viewport-hint {
    font-size: 0.8rem;
  }

  .viewport-detail-grid {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .reference-diagram-card {
    min-height: auto;
  }

  .ref-card-header {
    font-size: 0.74rem;
    margin-bottom: 4px;
  }

  .ref-card-body {
    display: grid;
    grid-template-columns: 86px minmax(0, 1fr);
    align-items: center;
    gap: 8px;
  }

  .ref-svg { max-height: 74px; }

  .ref-legend {
    font-size: 0.72rem;
  }

  .unit-selector-field {
    align-items: stretch;
    flex-direction: column;
    gap: 8px;
    margin-top: 10px;
    padding-top: 10px;
    font-size: 0.84rem;
  }

  .sliders-card h3,
  .formulas-card h3 {
    margin-bottom: 12px;
    font-size: 0.98rem;
  }

  .slider-field {
    margin-bottom: 12px;
  }

  .slider-label-row {
    margin-bottom: 4px;
    font-size: 0.9rem;
  }

  .slant-display-row {
    margin-top: 8px;
    padding: 9px 12px;
    font-size: 0.88rem;
  }

  .stepper-bar {
    gap: 8px;
    padding: 10px;
  }

  .step-controls-four {
    grid-template-columns: 46px 46px minmax(0, 1fr) minmax(0, 1fr);
    gap: 6px;
  }

  .step-badge {
    padding: 6px 8px;
    font-size: .76rem;
  }

  .step-badge-button {
    text-align: center;
  }

  .btn-step-square {
    min-height: 40px;
    font-size: .95rem;
  }

  .btn-auto-inline {
    padding: 8px 8px;
    min-height: 40px;
    font-size: .76rem;
  }

  .step-info-block h2 {
    font-size: 1.08rem;
    margin-bottom: 6px;
  }

  .step-info-block p,
  .formula-expr,
  .formula-calc,
  .formula-title {
    font-size: 0.9rem;
  }

  .formula-row {
    padding: 10px 12px;
  }

  .action-buttons-row {
    flex-wrap: nowrap;
    gap: 8px;
  }

  .btn-step {
    flex: 1 1 50%;
    min-height: 42px;
    padding: 8px 10px;
    font-size: .84rem;
    border-radius: 12px;
  }

  .unit-select {
    width: 100%;
    font-size: 0.84rem;
  }
}

@media (max-width: 420px) {
  .module-hero {
    padding: 12px;
  }

  .hero-content h1 {
    font-size: 1.35rem;
  }

  .hero-content p {
    font-size: 0.9rem;
  }

  .canvas-container {
    height: 180px;
  }

  .shape-tab-btn {
    padding: 9px 8px;
    font-size: 0.86rem;
  }

  .viewport-title {
    font-size: 0.96rem;
  }

  .ref-card-body {
    grid-template-columns: 84px minmax(0, 1fr);
  }

  .tool-btn {
    font-size: 0.66rem;
  }
}


/* Step 4 Overlay Callout Labels on Canvas */
.canvas-overlay-labels {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 5;
}

.overlay-callout {
  position: absolute;
  padding: 6px 12px;
  border-radius: 12px;
  font-weight: 800;
  font-size: 0.86rem;
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.25);
  backdrop-filter: blur(8px);
  white-space: normal;
  max-width: min(76%, 340px);
  text-align: center;
  line-height: 1.3;
  animation: fadeInCallout 0.3s ease forwards;
}

.tag-gold {
  background: rgba(245, 158, 11, 0.92);
  color: #0f172a;
  border: 1px solid #fef08a;
}

.tag-purple {
  background: rgba(99, 102, 241, 0.92);
  color: #ffffff;
  border: 1px solid #c7d2fe;
}

.tag-cyan {
  background: rgba(2, 132, 199, 0.92);
  color: #ffffff;
  border: 1px solid #bae6fd;
}

.tag-orange {
  background: rgba(249, 115, 22, 0.92);
  color: #ffffff;
  border: 1px solid #fed7aa;
}

@keyframes fadeInCallout {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; }
}


/* Top-Left Reference Diagram Card */
.reference-diagram-card {
  position: relative;
  z-index: 1;
  background: rgba(15, 23, 42, 0.78);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 16px;
  padding: 14px;
  color: #ffffff;
  backdrop-filter: blur(10px);
  box-shadow: 0 8px 22px rgba(0, 0, 0, 0.22);
  max-width: none;
  min-height: 100%;
  pointer-events: none;
  transition: all 0.2s ease;
}

:root[data-theme="light"] .reference-diagram-card {
  background: rgba(255, 255, 255, 0.92);
  color: #0f172a;
  border-color: #cbd5e1;
  box-shadow: 0 8px 22px rgba(15, 23, 42, 0.12);
}

.ref-card-header {
  font-size: 0.78rem;
  font-weight: 800;
  margin-bottom: 6px;
  color: var(--mod-accent);
}

.ref-card-body {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
}

.ref-svg {
  width: 100%;
  max-height: 120px;
}

.ref-legend {
  display: flex;
  flex-direction: column;
  gap: 2px;
  width: 100%;
  font-size: 0.76rem;
  font-weight: 700;
}

.ref-legend-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

.legend-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}

.dot-gold { background: #facc15; }
.dot-green { background: #4ade80; }
.dot-orange { background: #fb923c; }



/* KaTeX Formula Typography & Layout */
.katex {
  font-size: 1.15em !important;
  line-height: 1.2 !important;
  color: inherit !important;
}

.katex-display {
  margin: 8px 0 !important;
  font-size: 1.25em !important;
}

.formula-derivation-card {
  background: var(--mod-surface);
  border: 1px solid var(--mod-border);
  border-radius: 18px;
  padding: 18px;
  box-shadow: var(--mod-shadow);
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.derivation-block {
  padding: 12px 14px;
  background: var(--mod-surface-alt);
  border: 1px solid var(--mod-border);
  border-left: 4px solid var(--mod-primary);
  border-radius: 14px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.derivation-block.highlight {
  border-left-color: var(--mod-accent);
  background: rgba(245, 158, 11, 0.08);
}

.derivation-header {
  font-size: 0.88rem;
  font-weight: 800;
  color: var(--mod-primary);
}

.derivation-steps {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-top: 4px;
}

.derivation-step-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.95rem;
  color: var(--mod-heading);
}

.step-label {
  font-size: 0.78rem;
  font-weight: 800;
  padding: 2px 8px;
  border-radius: 6px;
  background: rgba(99, 102, 241, 0.12);
  color: var(--mod-primary);
  white-space: nowrap;
}

.step-label.final {
  background: rgba(16, 185, 129, 0.15);
  color: var(--mod-green);
}

.ref-math-box {
  margin-top: 6px;
  padding-top: 6px;
  border-top: 1px dashed var(--mod-border);
  display: flex;
  flex-direction: column;
  gap: 4px;
  font-size: 0.82rem;
  width: 100%;
}

@media (max-width: 480px) {
  .katex {
    font-size: 1.05em !important;
  }
  .katex-display {
    font-size: 1.1em !important;
  }
  .derivation-block {
    padding: 10px;
  }
}


/* Semantic Color System & Interactive Highlights */
:root {
  --geo-base: #0284c7;
  --geo-lateral: #6366f1;
  --geo-radius: #facc15;
  --geo-height: #4ade80;
  --geo-slant: #fb923c;
}

:root[data-theme="dark"] {
  --geo-base: #38bdf8;
  --geo-lateral: #818cf8;
  --geo-radius: #facc15;
  --geo-height: #4ade80;
  --geo-slant: #fb923c;
}

/* Hide Labels State */
.hide-labels #referenceDiagramCard,
.hide-labels #overlayLabels {
  display: none !important;
  opacity: 0 !important;
  pointer-events: none !important;
}

/* Unit Selector Field */
.unit-selector-field {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid var(--mod-border);
  font-weight: 700;
  font-size: 0.92rem;
}

.unit-select {
  padding: 6px 12px;
  border-radius: 10px;
  border: 1px solid var(--mod-border);
  background: var(--mod-surface-alt);
  color: var(--mod-heading);
  font-weight: 800;
  font-size: 0.88rem;
  cursor: pointer;
  outline: none;
  transition: all 0.2s ease;
}

.unit-select:focus {
  border-color: var(--mod-primary);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

/* Interactive Derivation Blocks (Hover / Tap linkage) */
.derivation-block[data-highlight] {
  cursor: pointer;
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease;
  user-select: none;
}

.derivation-block[data-highlight]:hover,
.derivation-block[data-highlight]:focus-visible,
.derivation-block.is-active-highlight {
  transform: translateY(-2px);
  border-color: var(--mod-primary);
  box-shadow: 0 8px 20px rgba(99, 102, 241, 0.25);
  background: rgba(99, 102, 241, 0.12);
  outline: none;
}

.derivation-block[data-highlight="base"].is-active-highlight {
  border-left-color: var(--geo-base) !important;
  background: rgba(2, 132, 199, 0.15) !important;
}

.derivation-block[data-highlight="lateral"].is-active-highlight {
  border-left-color: var(--geo-lateral) !important;
  background: rgba(99, 102, 241, 0.15) !important;
}

.derivation-block[data-highlight="slant"].is-active-highlight {
  border-left-color: var(--geo-slant) !important;
  background: rgba(249, 115, 22, 0.15) !important;
}

.derivation-block[data-highlight="volume"].is-active-highlight {
  border-left-color: #10b981 !important;
  background: rgba(16, 185, 129, 0.15) !important;
}

/* Step 4 Formula Origin Disclosure Accordion */
.formula-origin-wrapper {
  margin-top: 14px;
}

.btn-formula-origin {
  width: 100%;
  padding: 10px 14px;
  background: var(--mod-surface-alt);
  border: 1px solid var(--mod-border);
  border-radius: 12px;
  color: var(--mod-primary);
  font-weight: 800;
  font-size: 0.92rem;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: all 0.2s ease;
}

.btn-formula-origin:hover {
  background: rgba(99, 102, 241, 0.12);
}

.formula-origin-content {
  display: none;
  padding: 14px;
  margin-top: 8px;
  background: var(--mod-surface-alt);
  border: 1px solid var(--mod-border);
  border-radius: 14px;
  animation: fadeInAccordion 0.25s ease forwards;
}

.formula-origin-content.open {
  display: block;
}

.origin-item {
  margin-bottom: 12px;
}

.origin-item:last-child {
  margin-bottom: 0;
}

.origin-item-title {
  font-size: 0.85rem;
  font-weight: 800;
  color: var(--mod-primary);
  margin-bottom: 4px;
}

@keyframes fadeInAccordion {
  from { opacity: 0; transform: translateY(-4px); }
  to { opacity: 1; }
}

@media (prefers-reduced-motion: reduce) {
  .derivation-block[data-highlight],
  .formula-origin-content,
  .overlay-callout {
    animation: none !important;
    transition: none !important;
  }
}


@media (max-width: 420px) {
  .step-controls-four {
    grid-template-columns: 42px 42px minmax(92px, 1fr) minmax(92px, 1fr);
    gap: 5px;
  }

  .btn-auto-inline,
  .step-badge {
    font-size: 0.72rem;
  }
}