/* ==========================================================================
   mathwithcye — KSSM Mathematics Form 4
   Chapter 1: Quadratic Functions and Equations in One Variable
   1.1 Quadratic Functions and Graphs
   Responsive Design System, Touchscreen Ready, Teacher Teaching Tool & Remote
   ========================================================================== */

:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --secondary: #0ea5e9;
  --secondary-light: #f0f9ff;
  --accent: #8b5cf6;
  --accent-light: #f5f3ff;
  --success: #10b981;
  --success-light: #ecfdf5;
  --warning: #f59e0b;
  --warning-light: #fffbeb;
  --danger: #ef4444;
  --danger-light: #fef2f2;
  --dark: #0f172a;
  --card-bg: #ffffff;
  --bg-page: #f8fafc;
  --border: #e2e8f0;
  --border-focus: #3b82f6;
  --text-main: #1e293b;
  --text-muted: #64748b;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-math: "KaTeX_Math", "Times New Roman", serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

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

body {
  font-family: var(--font-main);
  background-color: var(--bg-page);
  color: var(--text-main);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
}

/* Container */
.app-container {
  max-width: 1240px;
  margin: 0 auto;
  padding: 16px 20px 80px 20px;
}

/* Header */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 14px 20px;
  margin-bottom: 14px;
  box-shadow: var(--shadow-sm);
}

.brand-zone {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.logo-badge {
  display: flex;
  align-items: center;
  gap: 10px;
}

.logo-icon {
  font-size: 26px;
  background: linear-gradient(135deg, #2563eb, #8b5cf6);
  color: #fff;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 12px;
  box-shadow: 0 4px 10px rgba(37, 99, 235, 0.3);
}

.brand-title {
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--dark);
  letter-spacing: -0.5px;
  line-height: 1.1;
}

.brand-subtitle {
  font-size: 0.76rem;
  color: var(--text-muted);
  font-weight: 600;
}

.lesson-meta-badge {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.72rem;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 9999px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.chapter-badge { background: #e0e7ff; color: #3730a3; }
.subtopic-badge { background: #dbeafe; color: #1e40af; }
.tb-ref-badge { background: #f1f5f9; color: #475569; border: 1px solid var(--border); }

/* User Session Bar */
.user-session-bar {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.student-profile {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--bg-page);
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}

.avatar-icon { font-size: 1.2rem; }

.student-name-text {
  display: block;
  font-size: 0.84rem;
  font-weight: 700;
  color: var(--dark);
}

.student-class-text {
  display: block;
  font-size: 0.72rem;
  color: var(--text-muted);
}

.btn-text-edit {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 0.85rem;
  padding: 2px 4px;
  opacity: 0.7;
}
.btn-text-edit:hover { opacity: 1; }

.session-stats {
  display: flex;
  gap: 8px;
}

.stat-pill {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  background: #f1f5f9;
  border: 1px solid var(--border);
  padding: 5px 12px;
  border-radius: 9999px;
  font-size: 0.82rem;
  font-weight: 700;
  color: #334155;
}

.score-pill {
  background: #fef3c7;
  border-color: #fde68a;
  color: #92400e;
}

/* Lesson Progress Bar */
.progress-bar-wrapper {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 8px 16px;
  margin-bottom: 14px;
}

.progress-info {
  display: flex;
  justify-content: space-between;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.progress-track {
  height: 8px;
  background: #e2e8f0;
  border-radius: 9999px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, #2563eb, #10b981);
  transition: width 0.35s ease;
}

/* 6-Stage Navigation */
.stage-nav {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 8px;
  margin-bottom: 20px;
}

@media (max-width: 860px) {
  .stage-nav {
    grid-template-columns: repeat(3, 1fr);
  }
}
@media (max-width: 540px) {
  .stage-nav {
    grid-template-columns: repeat(2, 1fr);
  }
}

.stage-btn {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px 8px;
  text-align: center;
  cursor: pointer;
  transition: all 0.2s ease;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

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

.stage-btn.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #ffffff;
  box-shadow: 0 4px 10px rgba(37, 99, 235, 0.25);
}

.stage-btn .stage-tag {
  font-size: 0.68rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  opacity: 0.85;
}

.stage-btn .stage-title {
  font-size: 0.82rem;
  font-weight: 700;
}

/* Lesson Stage Sections */
.lesson-stage {
  display: none;
}
.lesson-stage.active {
  display: block;
}

.stage-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  margin-bottom: 24px;
}

.stage-header {
  margin-bottom: 20px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 14px;
}

.stage-badge {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 800;
  text-transform: uppercase;
  color: var(--primary);
  background: var(--primary-light);
  padding: 3px 8px;
  border-radius: 4px;
  margin-bottom: 6px;
}

.stage-heading {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--dark);
}

.stage-desc {
  font-size: 0.92rem;
  color: var(--text-muted);
  margin-top: 4px;
}

/* Hero & Profile Registration Card */
.hero-tag {
  display: inline-block;
  background: #e0e7ff;
  color: #3730a3;
  padding: 4px 10px;
  font-size: 0.78rem;
  font-weight: 700;
  border-radius: 9999px;
  margin-bottom: 12px;
}

.hero-lead {
  font-size: 1.05rem;
  color: #475569;
  margin-bottom: 20px;
}

.profile-input-card {
  background: #f8fafc;
  border: 1px dashed #cbd5e1;
  border-radius: var(--radius-sm);
  padding: 18px;
  margin-bottom: 24px;
}

.profile-input-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--dark);
  margin-bottom: 4px;
}

.form-row {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  align-items: flex-end;
  margin-top: 14px;
}

.form-group {
  flex: 1;
  min-width: 220px;
}

.form-group.align-end {
  flex: 0 0 auto;
}

label {
  display: block;
  font-size: 0.82rem;
  font-weight: 600;
  color: #475569;
  margin-bottom: 5px;
}

input[type="text"], input[type="number"] {
  width: 100%;
  padding: 9px 14px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  font-size: 0.92rem;
  background: #ffffff;
  color: var(--text-main);
}
input[type="text"]:focus, input[type="number"]:focus {
  border-color: var(--primary);
  outline: none;
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

/* Symbol Decoder Card */
.symbol-decoder-card {
  background: #ffffff;
  border: 2px solid #3b82f6;
  border-radius: var(--radius-md);
  padding: 20px;
  margin: 20px 0;
  box-shadow: var(--shadow-sm);
}

.decoder-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
}

.decoder-icon {
  font-size: 24px;
  background: #eff6ff;
  padding: 6px 10px;
  border-radius: 8px;
}

.decoder-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 14px;
}

.decoder-item {
  background: #f8fafc;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 12px 14px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.decoder-symbol-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: #e0e7ff;
  color: #3730a3;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  font-weight: 800;
  font-size: 1.05rem;
  width: fit-content;
}

.decoder-meaning {
  font-size: 0.86rem;
  color: #1e293b;
  font-weight: 600;
}

.decoder-formula {
  font-size: 0.95rem;
  color: var(--primary);
  font-weight: 700;
  margin: 2px 0;
}

.decoder-bm {
  font-size: 0.74rem;
  color: var(--text-muted);
  font-style: italic;
}

/* Dilemma & Standards Grid */
.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-bottom: 20px;
}
@media (max-width: 768px) {
  .grid-2 {
    grid-template-columns: 1fr;
  }
}

.dilemma-card {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 18px;
  box-shadow: var(--shadow-sm);
}

.dilemma-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--dark);
  margin-bottom: 8px;
}

.dilemma-desc {
  font-size: 0.88rem;
  color: #475569;
  line-height: 1.6;
}

.standards-box {
  background: #f8fafc;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 18px;
}

.standards-box h4 {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--dark);
  margin-bottom: 8px;
}

.standards-list {
  padding-left: 18px;
  font-size: 0.86rem;
  color: #334155;
  line-height: 1.6;
}

.spm-tip-box {
  margin-top: 14px;
  background: #eff6ff;
  padding: 10px 14px;
  border-radius: 8px;
  border-left: 3px solid #3b82f6;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-weight: 700;
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.2s;
  font-size: 0.9rem;
}
.btn-primary { background: var(--primary); color: #ffffff; }
.btn-primary:hover { background: var(--primary-hover); }
.btn-secondary { background: #e2e8f0; color: #1e293b; }
.btn-secondary:hover { background: #cbd5e1; }
.btn-outline { background: transparent; border: 1px solid var(--border); color: #334155; }
.btn-outline:hover { background: #f1f5f9; border-color: #94a3b8; }
.btn-sm { padding: 6px 12px; font-size: 0.8rem; }
.btn-lg { padding: 12px 24px; font-size: 1rem; }

.stage-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 24px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
}

/* Stage B Discovery Lab */
.lab-navigation {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.lab-tab-btn {
  padding: 8px 14px;
  background: #f1f5f9;
  border: 1px solid var(--border);
  border-radius: 9999px;
  font-size: 0.82rem;
  font-weight: 700;
  color: #475569;
  cursor: pointer;
  transition: all 0.2s;
}

.lab-tab-btn.active {
  background: var(--primary);
  color: #ffffff;
  border-color: var(--primary);
}

.interactive-panel {
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 20px;
  align-items: start;
}
@media (max-width: 860px) {
  .interactive-panel {
    grid-template-columns: 1fr;
  }
}

.canvas-zone {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 16px;
  display: flex;
  flex-direction: column;
  align-items: center;
  box-shadow: var(--shadow-sm);
}

.controls-zone {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.control-card {
  background: #f8fafc;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px;
}

.slider-group {
  margin-bottom: 12px;
}
.slider-group:last-child { margin-bottom: 0; }

.slider-header {
  display: flex;
  justify-content: space-between;
  font-size: 0.84rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.slider-val {
  color: var(--primary);
  font-family: var(--font-mono);
}

input[type="range"] {
  width: 100%;
  accent-color: var(--primary);
  cursor: pointer;
}

.readout-box {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 12px;
  font-size: 0.86rem;
  line-height: 1.6;
}

/* Stage C Worked Examples */
.ex-tabs-bar {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

.ex-tab-btn {
  padding: 8px 14px;
  background: #f8fafc;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.84rem;
  font-weight: 700;
  cursor: pointer;
}
.ex-tab-btn.active {
  background: var(--primary);
  color: #ffffff;
  border-color: var(--primary);
}

.example-card {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 20px;
}

.ex-step-block {
  margin-top: 18px;
  padding: 16px;
  background: #f8fafc;
  border-radius: var(--radius-sm);
  border-left: 4px solid var(--primary);
}

.step-options-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 10px;
  margin-top: 12px;
}

.step-opt-btn {
  padding: 10px 14px;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.9rem;
  text-align: left;
  transition: all 0.2s;
}
.step-opt-btn:hover { border-color: var(--primary); }
.step-opt-btn.correct { background: #dcfce7; border-color: #22c55e; color: #15803d; font-weight: 700; }
.step-opt-btn.incorrect { background: #fee2e2; border-color: #ef4444; color: #b91c1c; }

/* Stage D & E Practice Cards */
.guided-grid, .challenge-grid {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.practice-card {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 20px;
  box-shadow: var(--shadow-sm);
}

.practice-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.question-qnum {
  font-size: 0.84rem;
  font-weight: 800;
  color: var(--primary);
}

.difficulty-badge {
  font-size: 0.7rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 9999px;
  text-transform: uppercase;
}
.diff-foundation { background: #e0f2fe; color: #0369a1; }
.diff-intermediate { background: #fef3c7; color: #b45309; }
.diff-advanced { background: #fee2e2; color: #b91c1c; }

.question-content {
  font-size: 0.95rem;
  line-height: 1.6;
  margin-bottom: 14px;
}

.options-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.option-btn {
  padding: 10px 14px;
  background: #f8fafc;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  text-align: left;
  font-size: 0.9rem;
  transition: all 0.2s;
}
.option-btn:hover { background: #f1f5f9; border-color: #94a3b8; }
.option-btn.correct { background: #dcfce7; border-color: #22c55e; color: #15803d; font-weight: 700; }
.option-btn.incorrect { background: #fee2e2; border-color: #ef4444; color: #b91c1c; }

.feedback-box {
  margin-top: 12px;
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.86rem;
  line-height: 1.5;
}
.feedback-box.correct { background: #f0fdf4; border: 1px solid #bbf7d0; color: #166534; }
.feedback-box.incorrect { background: #fef2f2; border: 1px solid #fecaca; color: #991b1b; }

.hint-container {
  margin-top: 10px;
}
.hint-toggle-btn {
  background: none;
  border: none;
  color: var(--primary);
  font-size: 0.82rem;
  font-weight: 700;
  cursor: pointer;
  padding: 2px 0;
}
.hint-content-box.hidden, .hidden { display: none !important; }
.hint-step { margin-bottom: 4px; }
.hint-content-box {
  margin-top: 6px;
  padding: 8px 12px;
  background: #fffbeb;
  border: 1px solid #fef3c7;
  border-radius: var(--radius-sm);
  font-size: 0.82rem;
  color: #92400e;
}

/* Filter Chips */
.filter-chips-bar {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.filter-chip {
  padding: 6px 12px;
  border-radius: 9999px;
  background: #f1f5f9;
  border: 1px solid var(--border);
  font-size: 0.78rem;
  font-weight: 700;
  color: #475569;
  cursor: pointer;
}
.filter-chip.active {
  background: var(--dark);
  color: #ffffff;
  border-color: var(--dark);
}

/* Stage F Exit Ticket & Certificate */
.certificate-card {
  max-width: 680px;
  margin: 0 auto;
}

/* ==========================================================================
   CLASSROOM TEACHING TOOLBAR (PRESENTER OVERLAY & MODALS)
   ========================================================================== */
.teaching-toolbar {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 9995;
  background-color: #1e1b4b;
  color: #ffffff;
  border: 1px solid #4338ca;
  border-radius: 16px;
  padding: 0.6rem 0.85rem;
  box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.5);
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  user-select: none;
  transition: transform 0.25s ease;
}

.teaching-toolbar.minimized {
  display: none !important;
}

.toolbar-drag-handle {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  padding-bottom: 0.35rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.15);
}

.toolbar-drag-dots { color: #818cf8; font-size: 0.9rem; }
.toolbar-title { font-size: 0.75rem; font-weight: 700; text-transform: uppercase; color: #c7d2fe; }

.btn-toolbar-minimize {
  background: transparent;
  border: none;
  color: #c7d2fe;
  cursor: pointer;
  font-size: 0.75rem;
}

.toolbar-tools {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.tool-btn {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 52px;
  height: 52px;
  background-color: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 10px;
  color: #ffffff;
  cursor: pointer;
  transition: 0.15s ease;
  padding: 0.2rem;
  position: relative;
}

.tool-btn:hover {
  background-color: rgba(99, 102, 241, 0.35);
  border-color: #818cf8;
}

.tool-btn.active {
  background-color: #4f46e5;
  border-color: #a5b4fc;
  box-shadow: 0 0 12px rgba(99, 102, 241, 0.6);
}

.tool-icon { font-size: 1.25rem; line-height: 1; }
.tool-name { font-size: 0.65rem; font-weight: 600; margin-top: 0.2rem; color: #e0e7ff; }

.remote-badge-dot {
  position: absolute;
  top: 4px;
  right: 4px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #f59e0b;
}
.remote-badge-dot.connected {
  background: #10b981;
  box-shadow: 0 0 6px #10b981;
}

.toolbar-expand-pill {
  position: fixed;
  bottom: 20px;
  right: 24px;
  background: #1e1b4b;
  color: #ffffff;
  border: 1px solid #4338ca;
  padding: 8px 16px;
  border-radius: 9999px;
  font-size: 0.82rem;
  font-weight: 700;
  box-shadow: var(--shadow-md);
  cursor: pointer;
  z-index: 10001;
}
.toolbar-expand-pill.hidden { display: none !important; }

.teaching-layer {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  z-index: 9980;
  pointer-events: none;
}
.teaching-layer canvas {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
}
.teaching-layer.mode-pen { pointer-events: auto; cursor: crosshair; }
.teaching-layer.mode-eraser { pointer-events: auto; cursor: cell; }
.teaching-layer.mode-laser { pointer-events: auto; cursor: crosshair; }

.tool-toast-notification {
  position: fixed;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(15, 23, 42, 0.92);
  color: #ffffff;
  padding: 8px 16px;
  border-radius: 9999px;
  font-size: 0.85rem;
  font-weight: 700;
  z-index: 10005;
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
}
.tool-toast-notification.hidden { display: none !important; }

/* Mathematical Typography & Scaling */
.katex {
  font-size: 1.06em !important;
  text-rendering: geometricPrecision;
}

.math-fallback {
  font-family: var(--font-math);
  font-style: normal;
}
.math-var {
  font-family: var(--font-math);
  font-style: italic;
}
em.math-var {
  font-family: var(--font-math);
  font-style: italic;
}
.math-sym {
  font-family: var(--font-main);
  padding: 0 2px;
}
.math-frac {
  display: inline-flex;
  flex-direction: column;
  vertical-align: middle;
  text-align: center;
  padding: 0 2px;
  font-size: 0.9em;
}
.math-num {
  border-bottom: 1px solid currentColor;
  padding: 0 2px;
}
.math-den {
  padding: 0 2px;
}

/* ==========================================================================
   PRINT STYLESHEET
   ========================================================================== */
@media print {
  body {
    background: #ffffff !important;
    color: #000000 !important;
  }
  .app-header, .stage-nav, .progress-bar-wrapper, .stage-footer, 
  .no-print, .lab-navigation, .ex-tabs-bar, .filter-chips-bar,
  .teaching-toolbar, .teaching-layer, .toolbar-expand-pill {
    display: none !important;
  }
  .lesson-stage {
    display: none !important;
  }
  #stageF, #exitTicketReport {
    display: block !important;
  }
  .certificate-card {
    border: 2px solid #000000 !important;
    box-shadow: none !important;
    padding: 30px !important;
  }
}


/* ======================================================== */
/* INTEGRATED MILESTONES: MISCONCEPTION BUSTER & GOLDEN VAULT */
/* ======================================================== */
.misconception-card {
  background: #ffffff;
  border: 2px solid #fecaca;
  border-radius: 14px;
  padding: 24px;
  margin-top: 28px;
  margin-bottom: 20px;
  box-shadow: 0 4px 14px rgba(239, 68, 68, 0.08);
}
.misconception-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}
.misconception-badge {
  background: #ef4444;
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 800;
  padding: 4px 10px;
  border-radius: 999px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.misconception-title {
  font-size: 1.18rem;
  font-weight: 700;
  color: #1e293b;
  margin: 0;
}
.misconception-subtitle {
  font-size: 0.85rem;
  color: #64748b;
  margin-top: 2px;
}
.misconception-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(290px, 1fr));
  gap: 16px;
  margin-top: 14px;
}
.misconception-col {
  border-radius: 10px;
  padding: 16px 18px;
  font-size: 0.92rem;
  line-height: 1.55;
}
.misconception-col.error-col {
  background: #fef2f2;
  border: 1.5px solid #fca5a5;
  color: #991b1b;
}
.misconception-col.correct-col {
  background: #f0fdf4;
  border: 1.5px solid #86efac;
  color: #166534;
}
.col-label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-weight: 800;
  font-size: 0.95rem;
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}
.examiner-warning {
  margin-top: 14px;
  background: #fffbeb;
  border-left: 4px solid #f59e0b;
  padding: 10px 14px;
  border-radius: 0 8px 8px 0;
  font-size: 0.85rem;
  color: #92400e;
  line-height: 1.45;
}

/* THE SUMMARY VAULT & GOLDEN TAKEAWAY */
.summary-vault-card {
  background: #ffffff;
  border: 2px solid #e2e8f0;
  border-radius: 14px;
  padding: 24px;
  margin-bottom: 24px;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.04);
}
.vault-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}
.vault-badge {
  background: #4f46e5;
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 800;
  padding: 4px 10px;
  border-radius: 999px;
  text-transform: uppercase;
}
.formula-matrix-table {
  width: 100%;
  border-collapse: collapse;
  margin: 12px 0 20px 0;
  font-size: 0.9rem;
}
.formula-matrix-table th {
  background: #f8fafc;
  color: #475569;
  text-align: left;
  padding: 10px 12px;
  border-bottom: 2px solid #e2e8f0;
  font-weight: 700;
}
.formula-matrix-table td {
  padding: 10px 12px;
  border-bottom: 1px solid #f1f5f9;
  color: #1e293b;
  vertical-align: middle;
}
.golden-takeaway-card {
  background: linear-gradient(135deg, #fffbeb 0%, #fef3c7 50%, #fde68a 100%);
  border: 2px solid #f59e0b;
  border-radius: 12px;
  padding: 20px 24px;
  box-shadow: 0 6px 18px rgba(245, 158, 11, 0.15);
  margin-top: 14px;
  position: relative;
  overflow: hidden;
}
.golden-takeaway-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 8px;
}
.golden-badge {
  background: #d97706;
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 800;
  padding: 4px 10px;
  border-radius: 999px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}
.golden-takeaway-title {
  font-size: 1.15rem;
  font-weight: 800;
  color: #78350f;
  margin: 0;
}
.golden-rule-box {
  background: rgba(255, 255, 255, 0.92);
  border: 1px solid #fbbf24;
  border-radius: 8px;
  padding: 12px 16px;
  margin: 10px 0;
  font-size: 0.98rem;
  font-weight: 700;
  color: #92400e;
  line-height: 1.55;
}
.golden-mnemonic {
  font-size: 0.88rem;
  color: #b45309;
  font-style: italic;
  margin-top: 6px;
}
.cert-golden-takeaway {
  margin-top: 16px;
  padding: 12px 16px;
  background: #fef3c7;
  border: 1.5px dashed #f59e0b;
  border-radius: 8px;
  font-size: 0.85rem;
  color: #92400e;
  text-align: left;
}
@media print {
  .misconception-card,
  .summary-vault-card {
    display: none !important;
  }
  .cert-golden-takeaway {
    display: block !important;
  }
}