/* ==========================================================================
   The Thinking Experiment (PhysicsKit) - Projectile Motion Inquiry Lab
   Design System Compliance:
   - Primary Teal: #0f7e9b
   - Accent Amber: #d67b19
   - Pure White:   #ffffff
   - Surface:      rgba(255, 255, 255, 0.96)
   - Border:       #c8dbe3
   - High-Contrast Text: #123140
   - Strict Prohibition: NO Purple (#59118e), NO Gold (#ffc61e)
   ========================================================================== */

@import url("https://fonts.googleapis.com/css2?family=IBM+Plex+Sans:wght@400;500;600;700&family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;600;700&display=swap");

:root {
  /* The Thinking Experiment Palette (Strict) */
  --primary-teal: #0f7e9b;
  --primary-teal-dark: #095f76;
  --primary-teal-light: #e6f4f8;
  --primary-teal-border: #a9c4cf;
  
  --accent-amber: #d67b19;
  --accent-amber-dark: #b06210;
  --accent-amber-light: #fdf3e8;
  --accent-amber-border: #f2cca1;
  --accent-amber-glow: rgba(214, 123, 25, 0.22);

  --bg-950: #e9f4fb;
  --bg-900: #fff4dd;
  --bg-800: #ffffff;
  --surface: rgba(255, 255, 255, 0.96);
  --surface-alt: rgba(247, 252, 255, 0.98);
  
  --ink: #123140;
  --muted: #4b6570;
  --subtle: #7a94a0;
  --border: #c8dbe3;
  --border-light: #e2eef3;

  --success: #1a7f4e;
  --success-bg: #ecfdf5;
  --success-border: #a7f3d0;

  --error: #dc2626;
  --error-bg: #fef2f2;
  --error-border: #fecaca;

  --shadow-sm: 0 2px 6px rgba(12, 54, 68, 0.05);
  --shadow-md: 0 6px 16px rgba(12, 54, 68, 0.08);
  --shadow-lg: 0 12px 24px rgba(12, 54, 68, 0.12);

  --app-bg:
    radial-gradient(1200px 700px at 8% 2%, rgba(19, 143, 176, 0.16), transparent 62%),
    radial-gradient(900px 600px at 92% 98%, rgba(214, 123, 25, 0.14), transparent 66%),
    linear-gradient(165deg, #e9f4fb, #fff4dd);

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-xl: 18px;
}

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

html, body {
  min-height: 100%;
}

body {
  font-family: "Inter", "IBM Plex Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--app-bg);
  color: var(--ink);
  line-height: 1.45;
  padding-bottom: 3.5rem;
  overflow-x: hidden;
}

/* Background blueprint grid matching Hub */
.bg-grid {
  position: fixed;
  inset: 0;
  z-index: -1;
  background-image:
    linear-gradient(rgba(15, 126, 155, 0.06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(214, 123, 25, 0.06) 1px, transparent 1px);
  background-size: 44px 44px;
  mask-image: radial-gradient(circle at center, black 42%, transparent 95%);
}

.math-expr {
  font-family: "Cambria Math", "Times New Roman", serif;
  font-style: italic;
  letter-spacing: 0.02em;
}

.shell {
  width: min(1440px, calc(100% - 2rem));
  margin-inline: auto;
  padding-top: 1rem;
}

/* ==========================================================================
   Header matching Hub Card Hero
   ========================================================================== */

.hero {
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.6rem;
  background: linear-gradient(160deg, #ffffff, #f7fbfd);
  box-shadow: var(--shadow-lg);
  position: relative;
  overflow: hidden;
  margin-bottom: 1rem;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 12px;
  background: var(--primary-teal);
  border-radius: var(--radius-lg) 0 0 var(--radius-lg);
}

.hero-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: 1rem;
  padding-left: 0.4rem;
}

.brand-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: var(--primary-teal-light);
  color: var(--primary-teal-dark);
  border: 1px solid var(--primary-teal-border);
  font-size: 0.8rem;
  font-weight: 600;
  padding: 0.25rem 0.65rem;
  border-radius: 999px;
  text-decoration: none;
  transition: background 0.2s, transform 0.15s;
}

.brand-badge:hover {
  background: #d5edf5;
  transform: translateY(-1px);
}

.lab-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: var(--accent-amber-light);
  color: var(--accent-amber-dark);
  border: 1px solid var(--accent-amber-border);
  font-size: 0.8rem;
  font-weight: 600;
  padding: 0.25rem 0.65rem;
  border-radius: 999px;
}

.guide-btn-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: #ffffff;
  color: var(--primary-teal-dark);
  border: 1px solid var(--primary-teal-border);
  font-size: 0.8rem;
  font-weight: 600;
  padding: 0.25rem 0.75rem;
  border-radius: 999px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.guide-btn-badge:hover {
  background: var(--primary-teal-light);
  border-color: var(--primary-teal);
  transform: translateY(-1px);
}

.hero h1 {
  font-family: "IBM Plex Sans", "Inter", sans-serif;
  font-size: clamp(1.4rem, 2.2vw, 1.95rem);
  font-weight: 700;
  color: var(--primary-teal-dark);
  margin-top: 0.25rem;
  letter-spacing: -0.015em;
}

.hero-subtitle {
  font-size: 0.92rem;
  color: var(--muted);
  max-width: 960px;
  margin-top: 0.35rem;
  line-height: 1.5;
}

/* ==========================================================================
   Interactive Activity Guide Drawer (Collapsible)
   ========================================================================== */

.activity-guide-drawer {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.5rem;
  margin-bottom: 1.25rem;
  box-shadow: var(--shadow-md);
  display: none;
}

.activity-guide-drawer.open {
  display: block;
  animation: slideDown 0.25s ease-out;
}

@keyframes slideDown {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: translateY(0); }
}

.guide-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.25rem;
  margin-top: 0.85rem;
}

.guide-card-item {
  background: var(--surface-alt);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 1rem;
}

.guide-card-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--primary-teal-dark);
  display: flex;
  align-items: center;
  gap: 0.4rem;
  margin-bottom: 0.4rem;
}

.guide-card-item p {
  font-size: 0.82rem;
  color: var(--muted);
  line-height: 1.45;
  margin-bottom: 0.4rem;
}

.guide-card-item ol {
  padding-left: 1.2rem;
  font-size: 0.8rem;
  color: var(--ink);
  line-height: 1.45;
}

/* ==========================================================================
   Mode Navigation Tabs (Elevated Brand Pills)
   ========================================================================== */

.mode-nav-bar {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-bottom: 1rem;
  overflow-x: auto;
  padding-bottom: 0.2rem;
}

.mode-pill-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: #ffffff;
  border: 1px solid var(--border);
  color: var(--muted);
  font-family: "IBM Plex Sans", "Inter", sans-serif;
  font-size: 0.9rem;
  font-weight: 600;
  padding: 0.55rem 1.15rem;
  border-radius: var(--radius-md);
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: all 0.18s ease;
  white-space: nowrap;
}

.mode-pill-btn:hover {
  background: var(--primary-teal-light);
  border-color: var(--primary-teal-border);
  color: var(--primary-teal-dark);
}

.mode-pill-btn.active {
  background: var(--primary-teal);
  color: #ffffff;
  border-color: var(--primary-teal-dark);
  box-shadow: 0 4px 12px rgba(15, 126, 155, 0.28);
}

/* ==========================================================================
   Main Layout Grid
   ========================================================================== */

.layout-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
}

@media (min-width: 1180px) {
  .layout-grid {
    grid-template-columns: minmax(0, 1.55fr) minmax(380px, 1fr);
  }
}

.stage-column,
.controls-column {
  display: flex;
  flex-direction: column;
  gap: 1.15rem;
}

/* ==========================================================================
   Status & Inquiry Goal Banner (Lock Banner Style)
   ========================================================================== */

.lock-banner {
  border-radius: var(--radius-md);
  padding: 0.45rem 0.95rem;
  font-size: 0.82rem;
  font-weight: 500;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.25rem;
  height: 72px;
  min-height: 72px;
  max-height: 72px;
  box-sizing: border-box;
  overflow: hidden;
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  background: #ffffff;
  flex-shrink: 0;
  transition: border-color 0.2s ease, background 0.2s ease;
}

.lock-banner.ready {
  border-left: 5px solid var(--primary-teal);
  background: linear-gradient(90deg, var(--primary-teal-light), #ffffff 40%);
}

.lock-banner.running {
  border-left: 5px solid var(--accent-amber);
  background: linear-gradient(90deg, var(--accent-amber-light), #ffffff 40%);
}

.lock-banner.hit {
  border-left: 5px solid var(--success);
  background: linear-gradient(90deg, var(--success-bg), #ffffff 40%);
}

.lock-banner.miss {
  border-left: 5px solid var(--error);
  background: linear-gradient(90deg, var(--error-bg), #ffffff 40%);
}

.lock-banner-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.5rem;
  line-height: 1;
}

.lock-banner-badge {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.73rem;
  font-weight: 700;
  text-transform: uppercase;
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-sm);
  background: #ffffff;
  border: 1px solid var(--border);
  color: var(--ink);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 75%;
}

.lock-banner-sub {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 0.15rem 0.45rem;
  border-radius: var(--radius-sm);
  flex-shrink: 0;
}

.lock-banner.ready .lock-banner-sub {
  background: var(--primary-teal-light);
  color: var(--primary-teal-dark);
}

.lock-banner.running .lock-banner-sub {
  background: var(--accent-amber-light);
  color: var(--accent-amber-dark);
}

.lock-banner.hit .lock-banner-sub {
  background: var(--success-bg);
  color: var(--success);
}

.lock-banner.miss .lock-banner-sub {
  background: var(--error-bg);
  color: var(--error);
}

.lock-banner-text {
  font-size: 0.81rem;
  font-weight: 500;
  color: var(--ink);
  line-height: 1.25;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ==========================================================================
   Cards
   ========================================================================== */

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  padding: 1.15rem;
  position: relative;
}

.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-bottom: 0.85rem;
  padding-bottom: 0.65rem;
  border-bottom: 1px solid var(--border-light);
}

.card-title {
  font-family: "IBM Plex Sans", "Inter", sans-serif;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--primary-teal-dark);
  display: flex;
  align-items: center;
  gap: 0.45rem;
}

/* ==========================================================================
   Canvas Simulation Stage
   ========================================================================== */

.simulation-viewport {
  position: relative;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: inset 0 2px 8px rgba(12, 54, 68, 0.04);
}

#simCanvas {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  background: #ffffff;
  cursor: crosshair;
}

/* Floating Toolbar over Canvas */
.canvas-floating-controls {
  position: absolute;
  top: 0.75rem;
  right: 0.75rem;
  display: flex;
  gap: 0.35rem;
  z-index: 10;
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: blur(8px);
  padding: 0.3rem 0.4rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  flex-wrap: wrap;
}

.tool-toggle-btn {
  background: transparent;
  border: 1px solid transparent;
  color: var(--muted);
  font-size: 0.76rem;
  font-weight: 600;
  padding: 0.28rem 0.55rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  transition: all 0.15s ease;
}

.tool-toggle-btn:hover {
  background: var(--primary-teal-light);
  color: var(--primary-teal-dark);
}

.tool-toggle-btn.active {
  background: var(--primary-teal);
  color: #ffffff;
  border-color: var(--primary-teal-dark);
}

.canvas-overlay-hints {
  position: absolute;
  bottom: 8px;
  left: 12px;
  background: rgba(255, 255, 255, 0.90);
  backdrop-filter: blur(4px);
  padding: 4px 8px;
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  color: var(--muted);
  border: 1px solid var(--border);
  pointer-events: none;
}

/* Canvas Primary Controls Bar below Canvas */
.sim-controls-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 0.85rem;
  padding: 0.75rem 1rem;
  background: var(--surface-alt);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
}

.action-btn-group {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  font-family: inherit;
  font-size: 0.88rem;
  font-weight: 600;
  padding: 0.5rem 1.05rem;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.18s ease;
  user-select: none;
}

.btn-primary {
  background: var(--accent-amber);
  color: #ffffff;
  border-color: var(--accent-amber-dark);
  box-shadow: 0 2px 6px rgba(214, 123, 25, 0.28);
}

.btn-primary:hover:not(:disabled) {
  background: var(--accent-amber-dark);
  transform: translateY(-1px);
  box-shadow: 0 4px 10px rgba(214, 123, 25, 0.36);
}

.btn-teal {
  background: var(--primary-teal);
  color: #ffffff;
  border-color: var(--primary-teal-dark);
  box-shadow: 0 2px 6px rgba(15, 126, 155, 0.25);
}

.btn-teal:hover:not(:disabled) {
  background: var(--primary-teal-dark);
  transform: translateY(-1px);
  box-shadow: 0 4px 10px rgba(15, 126, 155, 0.35);
}

.btn-secondary {
  background: #ffffff;
  color: var(--ink);
  border-color: var(--border);
}

.btn-secondary:hover:not(:disabled) {
  background: var(--primary-teal-light);
  border-color: var(--primary-teal-border);
  color: var(--primary-teal-dark);
}

.btn-amber-outline {
  background: var(--accent-amber-light);
  color: var(--accent-amber-dark);
  border: 1px solid var(--accent-amber-border);
}

.btn-amber-outline:hover:not(:disabled) {
  background: var(--accent-amber);
  color: #ffffff;
  border-color: var(--accent-amber-dark);
  transform: translateY(-1px);
}

.btn-sm {
  padding: 0.35rem 0.75rem;
  font-size: 0.8rem;
  border-radius: var(--radius-sm);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

/* Speed control selector */
.speed-selector {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.82rem;
  color: var(--muted);
}

.speed-pill {
  background: #ffffff;
  border: 1px solid var(--border);
  color: var(--ink);
  font-size: 0.76rem;
  font-weight: 600;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.15s ease;
}

.speed-pill:hover {
  border-color: var(--primary-teal);
}

.speed-pill.active {
  background: var(--primary-teal);
  color: #ffffff;
  border-color: var(--primary-teal-dark);
}

.gravity-pill {
  background: #ffffff;
  border: 1px solid var(--border);
  color: var(--ink);
  font-size: 0.74rem;
  font-weight: 600;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.15s ease;
}

.gravity-pill:hover {
  border-color: var(--primary-teal);
  color: var(--primary-teal-dark);
}

.gravity-pill.active {
  background: var(--primary-teal);
  color: #ffffff;
  border-color: var(--primary-teal-dark);
}

/* Presets Bar */
.preset-bar {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-top: 0.75rem;
  padding: 0.65rem 0.85rem;
  background: var(--surface-alt);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
}

.preset-label {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--primary-teal-dark);
  margin-right: 0.2rem;
}

.preset-pill {
  background: #ffffff;
  border: 1px solid var(--border);
  color: var(--ink);
  font-size: 0.78rem;
  font-weight: 600;
  padding: 0.25rem 0.65rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.15s ease;
}

.preset-pill:hover {
  background: var(--primary-teal-light);
  border-color: var(--primary-teal-border);
  color: var(--primary-teal-dark);
}

.preset-pill.active {
  background: var(--primary-teal);
  color: #ffffff;
  border-color: var(--primary-teal-dark);
}

/* ==========================================================================
   Telemetry Console (Digital Readouts)
   ========================================================================== */

.telemetry-console {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
  gap: 0.75rem;
  margin-top: 0.85rem;
}

.tele-box {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.65rem 0.85rem;
}

.tele-box-label {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--subtle);
  margin-bottom: 0.2rem;
}

.tele-box-value {
  font-family: "JetBrains Mono", monospace;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--primary-teal-dark);
}

/* ==========================================================================
   Right Column Tabs (Organized & Uncluttered)
   ========================================================================== */

.tab-nav-pills {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.4rem;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.6rem;
  margin-bottom: 0.85rem;
  overflow: hidden;
}

.tab-pill {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  background: var(--surface-alt);
  border: 1px solid var(--border-light);
  font-size: 0.76rem;
  font-weight: 600;
  color: var(--muted);
  padding: 0.45rem 0.35rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.15s ease;
  white-space: normal;
  text-align: center;
  line-height: 1.2;
}

.tab-pill:hover {
  color: var(--primary-teal-dark);
  background: var(--primary-teal-light);
  border-color: var(--primary-teal-border);
}

.tab-pill.active {
  background: var(--primary-teal);
  color: #ffffff;
  border-color: var(--primary-teal);
  box-shadow: 0 2px 4px rgba(15, 126, 155, 0.25);
}

.panel-tab-content {
  display: none;
  overflow-x: hidden;
}

.panel-tab-content.active {
  display: block;
}

/* Parameter Sliders */
.param-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.85rem;
}

.param-item {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.param-label-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--ink);
}

.param-val-badge {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--primary-teal-dark);
  background: var(--primary-teal-light);
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--primary-teal-border);
}

.range-slider {
  width: 100%;
  accent-color: var(--accent-amber);
  cursor: pointer;
  height: 6px;
  border-radius: 3px;
}

.select-input {
  background-color: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.45rem 0.7rem;
  font-size: 0.85rem;
  color: var(--ink);
  cursor: pointer;
}

.select-input:focus {
  outline: none;
  border-color: var(--primary-teal);
}

/* ==========================================================================
   Math Formula Rendering (CSS Stacked Fractions & Typographic Beauty)
   ========================================================================== */

.math-solution-box {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 0.85rem;
  margin-top: 0.5rem;
  box-shadow: var(--shadow-sm);
  overflow-x: hidden;
}

.math-title {
  font-size: 0.86rem;
  font-weight: 700;
  color: var(--primary-teal-dark);
  margin-bottom: 0.6rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.35rem;
}

/* ==========================================================================
   Inquiry Scenario & Problem Statement Collapsible Card
   ========================================================================== */

.inquiry-scenario-card {
  background: #ffffff;
  border: 1px solid var(--border-light);
  border-left: 4px solid var(--primary-teal);
  border-radius: var(--radius-md);
  margin-bottom: 0.85rem;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: all 0.2s ease;
}

.inquiry-scenario-card:hover {
  border-color: #b7e0ee;
  box-shadow: 0 2px 8px rgba(15, 126, 155, 0.08);
}

.inquiry-scenario-card.open {
  border-color: var(--primary-teal-border);
  box-shadow: 0 4px 14px rgba(15, 126, 155, 0.12);
}

.inquiry-header {
  padding: 0.65rem 0.95rem;
  cursor: pointer;
  user-select: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  background: #ffffff;
  transition: background 0.15s ease;
}

.inquiry-header:hover {
  background: #f7fcfe;
}

.inquiry-scenario-card.open .inquiry-header {
  background: #f1f9fc;
  border-bottom: 1px solid #e1eff5;
}

.inquiry-header-left {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  flex: 1 1 auto;
  min-width: 0;
  flex-wrap: wrap;
}

.inquiry-header-icon {
  font-size: 1.15rem;
  flex-shrink: 0;
}

.inquiry-header-text {
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
}

.inquiry-title {
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--primary-teal-dark);
  margin: 0;
  line-height: 1.25;
}

.inquiry-subtitle {
  font-size: 0.76rem;
  color: var(--muted);
  font-weight: 500;
}

.inquiry-tag {
  font-size: 0.66rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--primary-teal-dark);
  background: var(--primary-teal-light);
  padding: 0.2rem 0.55rem;
  border-radius: 999px;
  border: 1px solid var(--primary-teal-border);
  white-space: nowrap;
}

.inquiry-toggle-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: var(--surface-alt);
  border: 1px solid var(--border-light);
  color: var(--primary-teal-dark);
  padding: 0.3rem 0.65rem;
  border-radius: 999px;
  font-size: 0.74rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s ease;
  flex-shrink: 0;
}

.inquiry-toggle-btn:hover {
  background: var(--primary-teal-light);
  border-color: var(--primary-teal);
}

.toggle-chevron {
  font-size: 0.72rem;
  transition: transform 0.2s ease;
  display: inline-block;
}

.inquiry-scenario-card.open .toggle-chevron {
  transform: rotate(180deg);
}

.inquiry-body {
  display: none;
  padding: 0.95rem 1.15rem;
  flex-direction: column;
  gap: 0.85rem;
  background: #ffffff;
  animation: fadeIn 0.2s ease-in-out;
}

.inquiry-scenario-card.open .inquiry-body {
  display: flex;
}

.inquiry-narrative-box {
  background: #fafcfe;
  border: 1px solid #e1eff5;
  border-radius: var(--radius-sm);
  padding: 0.75rem 0.95rem;
}

.inquiry-section-label {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--primary-teal);
  margin-bottom: 0.35rem;
}

.inquiry-narrative {
  font-size: 0.86rem;
  color: var(--ink);
  line-height: 1.55;
  margin: 0;
}

.inquiry-questions-box {
  background: #ffffff;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  padding: 0.75rem 0.95rem;
}

.inquiry-questions-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.55rem;
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--accent-amber-dark);
}

.inquiry-q-count {
  font-size: 0.68rem;
  font-weight: 600;
  color: var(--muted);
  background: var(--surface-alt);
  padding: 0.15rem 0.45rem;
  border-radius: 999px;
  border: 1px solid var(--border-light);
}

.inquiry-questions-list {
  padding-left: 1.15rem;
  margin: 0;
  font-size: 0.84rem;
  line-height: 1.6;
  color: var(--ink);
}

.inquiry-questions-list li {
  margin-bottom: 0.45rem;
}

.inquiry-questions-list li:last-child {
  margin-bottom: 0;
}

.q-badge {
  display: inline-block;
  font-weight: 700;
  color: var(--primary-teal-dark);
  background: var(--primary-teal-light);
  padding: 0.1rem 0.4rem;
  border-radius: 4px;
  margin-right: 0.3rem;
  font-size: 0.78rem;
  border: 1px solid var(--primary-teal-border);
}

/* ==========================================================================
   Collapsible Step-by-Step Pedagogical Math Cards
   ========================================================================== */

.math-step-card {
  background: var(--surface-alt);
  border: 1px solid var(--border-light);
  border-left: 3.5px solid var(--primary-teal);
  border-radius: var(--radius-sm);
  margin-bottom: 0.65rem;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.math-step-card.accent-amber {
  border-left-color: var(--accent-amber);
}

.math-step-card.accent-dark {
  border-left-color: var(--primary-teal-dark);
}

.math-step-header {
  padding: 0.65rem 0.85rem;
  cursor: pointer;
  user-select: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--surface-alt);
  transition: background 0.15s ease;
}

.math-step-header:hover {
  background: #eef6f9;
}

.math-step-title {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.84rem;
  font-weight: 700;
  color: var(--primary-teal-dark);
}

.math-step-chevron {
  font-size: 0.72rem;
  color: var(--muted);
  transition: transform 0.2s ease;
}

.math-step-card.open .math-step-chevron {
  transform: rotate(180deg);
}

.math-step-body {
  display: none;
  padding: 0.65rem 0.85rem;
  border-top: 1px solid var(--border-light);
  background: #ffffff;
  flex-direction: column;
  gap: 0.5rem;
}

.math-step-card.open .math-step-body {
  display: flex;
}

.math-step-row {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  padding: 0.4rem 0.55rem;
  background: #ffffff;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  font-size: 0.84rem;
  color: var(--ink);
  line-height: 1.4;
  overflow-x: hidden;
}

.math-step-label {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--subtle);
}

.math-step-math {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.3rem;
  font-family: "JetBrains Mono", monospace;
  font-size: 0.82rem;
  word-break: break-word;
}

.math-eq-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.4rem;
  padding: 0.55rem 0.75rem;
  background: var(--surface-alt);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  margin-bottom: 0.65rem;
  font-size: 0.88rem;
  color: var(--ink);
  overflow-x: hidden;
}

/* Stacked Fraction Typography */
.fraction {
  display: inline-flex;
  flex-direction: column;
  vertical-align: middle;
  text-align: center;
  padding: 0 0.3rem;
  font-size: 0.9em;
  line-height: 1.1;
}

.fraction .num {
  border-bottom: 1.5px solid var(--ink);
  padding-bottom: 2px;
}

.fraction .den {
  padding-top: 2px;
}

.math-eval-tag {
  font-family: "JetBrains Mono", monospace;
  font-weight: 700;
  color: var(--primary-teal-dark);
  background: #ffffff;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--primary-teal-border);
}

.status-badge-inline {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius-sm);
  font-size: 0.82rem;
  font-weight: 600;
}

.status-badge-inline.safe {
  background: var(--success-bg);
  color: var(--success);
  border: 1px solid var(--success-border);
}

.status-badge-inline.warn {
  background: var(--error-bg);
  color: var(--error);
  border: 1px solid var(--error-border);
}

/* ==========================================================================
   Cornell Kinematics T-Chart Card
   ========================================================================== */

.tchart-container {
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
  background: #ffffff;
  margin-top: 0.75rem;
}

.tchart-grid {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
}

.tchart-col {
  padding: 0.85rem;
}

.tchart-left {
  border-right: 1px solid var(--border);
}

.tchart-col-head {
  font-family: "IBM Plex Sans", "Inter", sans-serif;
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--primary-teal-dark);
  border-bottom: 2px solid var(--primary-teal-light);
  padding-bottom: 0.35rem;
  margin-bottom: 0.55rem;
}

.tchart-law {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--accent-amber);
  margin-bottom: 0.35rem;
}

.tchart-formula {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.76rem;
  color: var(--muted);
  margin-top: 0.45rem;
}

.tchart-val {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.76rem;
  color: var(--primary-teal-dark);
  background: var(--primary-teal-light);
  padding: 0.2rem 0.4rem;
  border-radius: 4px;
  margin-top: 0.2rem;
  display: inline-block;
}

.tchart-bridge {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: var(--primary-teal-light);
  padding: 0.5rem 0.75rem;
  border-right: 1px solid var(--border);
}

.bridge-circle {
  background: var(--accent-amber);
  color: #ffffff;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: "Cambria Math", serif;
  font-style: italic;
  font-weight: 700;
  font-size: 1.1rem;
  box-shadow: 0 0 10px var(--accent-amber-glow);
}

.bridge-tag {
  font-size: 0.6rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--primary-teal-dark);
  margin-top: 0.25rem;
  font-weight: 700;
}

/* ==========================================================================
   Trial Table
   ========================================================================== */

.table-scroll {
  overflow-x: auto;
  max-height: 220px;
  margin-top: 0.75rem;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.8rem;
}

.data-table th {
  background: var(--surface-alt);
  color: var(--muted);
  font-weight: 600;
  padding: 0.45rem 0.65rem;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}

.data-table td {
  padding: 0.45rem 0.65rem;
  border-bottom: 1px solid var(--border-light);
  font-family: "JetBrains Mono", monospace;
  white-space: nowrap;
}

/* Challenge Section */
.challenge-box {
  background: var(--surface-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1rem;
  margin-top: 0.85rem;
}

.radio-row {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  margin: 0.65rem 0;
}

.radio-item {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  font-size: 0.85rem;
  cursor: pointer;
}

.radio-item input {
  accent-color: var(--accent-amber);
}

/* Footer */
.footer {
  margin-top: 2rem;
  text-align: center;
  font-size: 0.82rem;
  color: var(--muted);
}

/* Stacked Kinematics Motion Graphs */
.stacked-canvas-container {
  position: relative;
  width: 100%;
  height: 420px;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
  cursor: crosshair;
}

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

.graph-legend-pills {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  font-size: 0.78rem;
}

.graph-legend-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-size: 0.76rem;
  color: var(--muted);
}