/* ==========================================================================
   DBMS Exam Mastery Platform - Complete Modern Stylesheet
   Mobile-Responsive, Dark/Light Themes, Clean Typography & Components
   ========================================================================== */

:root,
body.dark-theme {
  --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'Fira Code', 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;

  /* Dark Theme Palette (Refined Modern Depth) */
  --bg-primary: #0a0e17;
  --bg-secondary: #131924;
  --bg-tertiary: #1b2333;
  --bg-elevated: #242e42;
  --bg-hover: #2d3850;
  --bg-glass: rgba(19, 25, 36, 0.85);
  
  --border-color: #2b3548;
  --border-subtle: #1e2638;
  --border-focus: #3b82f6;
  --focus-ring: 0 0 0 3px rgba(59, 130, 246, 0.35);

  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --text-link: #60a5fa;

  --accent-primary: #3b82f6;
  --accent-hover: #2563eb;
  --accent-subtle: rgba(59, 130, 246, 0.16);
  --accent-glow: 0 0 16px rgba(59, 130, 246, 0.25);

  --success-color: #22c55e;
  --success-subtle: rgba(34, 197, 94, 0.16);
  --warning-color: #f59e0b;
  --warning-subtle: rgba(245, 158, 11, 0.16);
  --danger-color: #ef4444;
  --danger-subtle: rgba(239, 68, 68, 0.16);

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-pill: 9999px;

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.25);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.45);

  --header-height: 64px;
}

body.light-theme {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f1f5f9;
  --bg-elevated: #ffffff;
  --bg-hover: #e2e8f0;
  --bg-glass: rgba(255, 255, 255, 0.9);

  --border-color: #cbd5e1;
  --border-subtle: #e2e8f0;
  --border-focus: #2563eb;
  --focus-ring: 0 0 0 3px rgba(37, 99, 235, 0.25);

  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --text-link: #2563eb;

  --accent-primary: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-subtle: rgba(37, 99, 235, 0.12);
  --accent-glow: 0 0 16px rgba(37, 99, 235, 0.2);

  --success-color: #16a34a;
  --success-subtle: rgba(22, 163, 74, 0.12);
  --warning-color: #d97706;
  --warning-subtle: rgba(217, 119, 6, 0.12);
  --danger-color: #dc2626;
  --danger-subtle: rgba(220, 38, 38, 0.12);

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.12);
}

/* ==========================================================================
   Base Reset & Typography
   ========================================================================== */

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

html {
  scroll-behavior: smooth;
}

html, body {
  height: 100%;
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-size: 14px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

/* Accessibility: Universal High-Contrast Focus Ring */
:focus-visible {
  outline: 2px solid var(--accent-primary) !important;
  outline-offset: 2px !important;
  box-shadow: var(--focus-ring);
}

/* Custom Sleek Scrollbar */
::-webkit-scrollbar {
  width: 7px;
  height: 7px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: var(--radius-pill);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}

@media (prefers-reduced-motion: reduce) {
  *, ::before, ::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

code, pre, textarea.form-code {
  font-family: var(--font-mono);
}

a {
  color: var(--text-link);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */

.app-header {
  height: var(--header-height);
  background-color: var(--bg-glass);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border-color);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.25);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
  position: sticky;
  top: 0;
  z-index: 1000;
  gap: 16px;
}

.header-left {
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

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

.logo-icon {
  font-size: 22px;
  background: var(--accent-subtle);
  border: 1px solid var(--accent-primary);
  border-radius: var(--radius-md);
  padding: 5px 8px;
  box-shadow: 0 0 12px rgba(59, 130, 246, 0.25);
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.logo-text h1 {
  font-size: 17px;
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.logo-text .highlight {
  color: var(--accent-primary);
  text-shadow: 0 0 16px rgba(59, 130, 246, 0.35);
}

.logo-text .subtitle {
  font-size: 11px;
  color: var(--text-secondary);
  display: block;
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 360px;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 6px;
  overflow-x: auto;
  white-space: nowrap;
  padding: 4px 0;
  scrollbar-width: none;
}
.main-nav::-webkit-scrollbar {
  display: none;
}

.nav-tab {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 42px;
  padding: 8px 16px;
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  user-select: none;
}

.nav-tab:hover {
  background-color: var(--bg-hover);
  color: var(--text-primary);
  transform: translateY(-1px);
}

.nav-tab.active {
  background-color: var(--accent-subtle);
  border-color: rgba(59, 130, 246, 0.3);
  color: var(--accent-primary);
  font-weight: 700;
  box-shadow: var(--shadow-sm);
}

.nav-tab.active::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 15%;
  right: 15%;
  height: 3px;
  background: var(--accent-primary);
  border-radius: 3px 3px 0 0;
  box-shadow: 0 0 10px var(--accent-primary);
}

.nav-tab .badge {
  font-size: 10px;
  font-weight: 700;
  background-color: var(--bg-tertiary);
  color: var(--text-secondary);
  padding: 2px 8px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--border-color);
  letter-spacing: 0.02em;
}

.nav-tab.active .badge {
  background-color: var(--accent-primary);
  color: #fff;
  border-color: transparent;
  box-shadow: 0 0 8px rgba(59, 130, 246, 0.4);
}

.live-dot {
  width: 8px;
  height: 8px;
  background-color: var(--success-color);
  border-radius: 50%;
  display: inline-block;
  box-shadow: 0 0 8px var(--success-color);
  animation: statusPulse 2s infinite;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.header-shortcuts-badge {
  font-size: 11px;
  font-family: var(--font-mono);
  font-weight: 600;
  padding: 4px 8px;
  border-radius: var(--radius-sm);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  display: inline-flex;
  align-items: center;
  gap: 4px;
  user-select: none;
  letter-spacing: 0.02em;
}

.screenshot-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 12px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  white-space: nowrap;
}

.screenshot-btn:hover {
  background: var(--accent-subtle);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
  transform: translateY(-1px);
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.25);
}

.icon-btn {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  width: 38px;
  height: 38px;
  border-radius: var(--radius-md);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  transition: all 0.2s ease;
}

.icon-btn:hover {
  background: var(--bg-hover);
  border-color: var(--border-focus);
  transform: translateY(-1px);
}

.db-status-pill {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-pill);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.status-indicator {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  flex-shrink: 0;
}

@keyframes statusPulse {
  0% { box-shadow: 0 0 0 0 rgba(34, 197, 94, 0.7); }
  70% { box-shadow: 0 0 0 8px rgba(34, 197, 94, 0); }
  100% { box-shadow: 0 0 0 0 rgba(34, 197, 94, 0); }
}

.status-indicator.online {
  background-color: var(--success-color);
  box-shadow: 0 0 8px var(--success-color);
  animation: statusPulse 2s infinite;
}
.status-indicator.offline {
  background-color: var(--danger-color);
  box-shadow: 0 0 8px var(--danger-color);
}

/* ==========================================================================
   Main Content & Tabs
   ========================================================================== */

.app-main {
  min-height: calc(100% - var(--header-height));
  display: flex;
  flex-direction: column;
}

.tab-content {
  display: none;
  flex: 1;
}

.tab-content.active {
  display: flex;
  flex-direction: column;
}

/* Generic Card & UI Elements */
.card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 20px;
  box-shadow: var(--shadow-sm);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.card:hover {
  border-color: var(--border-light, #3b465c);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 38px;
  padding: 8px 18px;
  font-size: 13px;
  font-weight: 600;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.18s cubic-bezier(0.4, 0, 0.2, 1);
  user-select: none;
}

.btn:active {
  transform: scale(0.97);
}

.btn-primary {
  background: linear-gradient(135deg, #3b82f6, #1d4ed8);
  color: #ffffff;
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.35);
}
.btn-primary:hover {
  background: linear-gradient(135deg, #60a5fa, #2563eb);
  box-shadow: 0 6px 18px rgba(37, 99, 235, 0.45);
  transform: translateY(-1px);
}

.btn-secondary {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
  border-color: var(--border-color);
}
.btn-secondary:hover {
  background-color: var(--bg-hover);
  border-color: var(--border-focus);
  transform: translateY(-1px);
}

.btn-warning {
  background: linear-gradient(135deg, rgba(245, 158, 11, 0.2), rgba(217, 119, 6, 0.3));
  color: var(--warning-color);
  border-color: var(--warning-color);
}
.btn-warning:hover {
  background: var(--warning-color);
  color: #000;
  box-shadow: 0 4px 14px rgba(245, 158, 11, 0.35);
  transform: translateY(-1px);
}

.btn-danger {
  background: linear-gradient(135deg, #ef4444, #b91c1c);
  color: #fff;
  box-shadow: 0 4px 14px rgba(239, 68, 68, 0.35);
}
.btn-danger:hover {
  background: linear-gradient(135deg, #f87171, #dc2626);
  transform: translateY(-1px);
  box-shadow: 0 6px 18px rgba(239, 68, 68, 0.45);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  border-color: transparent;
}
.btn-ghost:hover {
  background-color: var(--bg-hover);
  color: var(--text-primary);
}

.btn-sm {
  min-height: 30px;
  padding: 5px 12px;
  font-size: 12px;
  font-weight: 600;
  border-radius: var(--radius-sm);
  cursor: pointer;
  border: 1px solid var(--border-color);
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  transition: all 0.18s ease;
}
.btn-sm:hover {
  background: var(--bg-hover);
  border-color: var(--border-focus);
  color: var(--text-primary);
}
.btn-sm:active {
  transform: scale(0.96);
}

.form-select, .form-input, .form-textarea {
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 9px 14px;
  border-radius: var(--radius-md);
  font-size: 13px;
  font-family: inherit;
  outline: none;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}
.form-select:focus, .form-input:focus, .form-textarea:focus {
  border-color: var(--border-focus);
  box-shadow: var(--focus-ring);
}

.search-box input {
  width: 100%;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 10px 16px;
  border-radius: var(--radius-md);
  font-size: 13px;
  font-family: inherit;
  outline: none;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}
.search-box input:focus {
  border-color: var(--border-focus);
  box-shadow: var(--focus-ring);
}
.search-box input:focus {
  border-color: var(--border-focus);
}

.badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: var(--radius-pill);
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
}

.badge-primary { background: var(--accent-subtle); color: var(--accent-primary); border: 1px solid var(--accent-primary); }
.badge-easy { background: var(--success-subtle); color: var(--success-color); border: 1px solid var(--success-color); }
.badge-medium { background: var(--warning-subtle); color: var(--warning-color); border: 1px solid var(--warning-color); }
.badge-hard { background: var(--danger-subtle); color: var(--danger-color); border: 1px solid var(--danger-color); }
.badge-favorite { background: #3d2600; color: #ffb800; border: 1px solid #ffb800; }

.empty-state {
  text-align: center;
  padding: 32px 16px;
  color: var(--text-muted);
  font-size: 14px;
}

/* ==========================================================================
   TAB 1: Study & Concept Master
   ========================================================================== */

.study-container {
  display: flex;
  flex: 1;
  height: calc(100vh - var(--header-height));
  overflow: hidden;
}

.study-sidebar {
  width: 320px;
  background-color: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  padding: 16px;
  gap: 16px;
  flex-shrink: 0;
  overflow-y: auto;
}

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

.study-day-btn {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: 10px 14px;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  cursor: pointer;
  text-align: left;
  transition: all 0.15s ease;
}

.study-day-btn:hover {
  background-color: var(--bg-hover);
  color: var(--text-primary);
}

.study-day-btn.active {
  background-color: var(--accent-subtle);
  border-color: var(--accent-primary);
  color: var(--text-primary);
}

.study-day-btn .day-num {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--accent-primary);
}

.study-day-btn .day-title {
  font-size: 13px;
  font-weight: 500;
  margin-top: 2px;
}

.quick-cheatsheet-card {
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  padding: 12px;
  border: 1px solid var(--border-color);
}

.quick-cheatsheet-card h4 {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 8px;
}

.quick-links {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.quick-link-btn {
  background: transparent;
  border: none;
  color: var(--text-link);
  font-size: 12px;
  text-align: left;
  padding: 4px 6px;
  border-radius: var(--radius-sm);
  cursor: pointer;
}
.quick-link-btn:hover {
  background: var(--bg-hover);
  text-decoration: underline;
}

.study-body {
  flex: 1;
  padding: 24px 32px;
  overflow-y: auto;
}

.study-header {
  margin-bottom: 24px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 16px;
}

.study-header h2 {
  font-size: 24px;
  font-weight: 700;
}

.study-desc {
  color: var(--text-secondary);
  font-size: 14px;
  margin-top: 4px;
}

.study-section-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  margin-bottom: 20px;
  overflow: hidden;
}

.study-section-card.collapsed .study-section-content {
  display: none !important;
}

.study-section-card.collapsed .study-section-header {
  border-bottom: none;
}

.study-section-header {
  padding: 14px 20px;
  background-color: var(--bg-tertiary);
  border-bottom: 1px solid var(--border-color);
  font-size: 16px;
  font-weight: 600;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
}

.study-section-header .toggle-icon {
  transition: transform 0.2s ease;
  user-select: none;
}

.study-section-card.collapsed .study-section-header .toggle-icon {
  transform: rotate(-90deg);
}

.study-section-header:hover {
  background-color: var(--bg-hover);
}

.study-section-content {
  padding: 20px;
  color: var(--text-primary);
  line-height: 1.7;
}

.study-section-content h3 { font-size: 18px; margin: 16px 0 8px 0; color: var(--accent-primary); }
.study-section-content h4 { font-size: 15px; margin: 12px 0 6px 0; color: var(--text-primary); }
.study-section-content p { margin-bottom: 12px; }
.study-section-content ul, .study-section-content ol { margin-left: 20px; margin-bottom: 12px; }
.study-section-content li { margin-bottom: 4px; }

.study-section-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: 13px;
}
.study-section-content th, .study-section-content td {
  border: 1px solid var(--border-color);
  padding: 8px 12px;
  text-align: left;
}
.study-section-content th {
  background-color: var(--bg-tertiary);
  font-weight: 600;
}
.study-section-content tr:nth-child(even) {
  background-color: var(--bg-tertiary);
}

.study-section-content pre {
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 14px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 13px;
  margin: 14px 0;
}

/* ==========================================================================
   TAB 2: 303 Practice Arena
   ========================================================================== */

.practice-container {
  padding: 20px 24px;
  max-width: 1300px;
  margin: 0 auto;
  width: 100%;
}

.practice-filters-bar {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 16px;
  margin-bottom: 20px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.day-pills {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 2px;
}

.filter-pill {
  padding: 6px 14px;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-pill);
  color: var(--text-secondary);
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.15s;
}

.filter-pill:hover {
  background-color: var(--bg-hover);
  color: var(--text-primary);
}

.filter-pill.active {
  background-color: var(--accent-primary);
  color: #fff;
  border-color: var(--accent-primary);
}

.filter-controls-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.practice-search {
  flex: 1;
  min-width: 250px;
}

.practice-stats-strip {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding-top: 10px;
  border-top: 1px solid var(--border-subtle);
}

.stats-info {
  display: flex;
  justify-content: space-between;
  font-size: 12px;
  color: var(--text-secondary);
}

.progress-bar-track {
  width: 100%;
  height: 6px;
  background-color: var(--bg-tertiary);
  border-radius: var(--radius-pill);
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  background-color: var(--success-color);
  transition: width 0.3s ease;
}

.practice-questions-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.question-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  transition: border-color 0.15s;
}

.question-card.completed {
  border-left: 4px solid var(--success-color);
}

.question-card-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 12px;
}

.question-meta-tags {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.question-actions-top {
  display: flex;
  align-items: center;
  gap: 10px;
}

.bookmark-btn {
  background: transparent;
  border: none;
  font-size: 18px;
  cursor: pointer;
  color: var(--text-muted);
  transition: transform 0.1s;
}
.bookmark-btn:hover {
  transform: scale(1.15);
}
.bookmark-btn.active {
  color: #ffb800;
}

.complete-check-label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  color: var(--text-secondary);
  cursor: pointer;
}

.question-title-text {
  font-size: 15px;
  font-weight: 500;
  line-height: 1.5;
  color: var(--text-primary);
  white-space: pre-line;
}

/* Question Accordions (Hints & Solution) */
.accordion-box {
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  overflow: hidden;
}

.accordion-toggle {
  width: 100%;
  padding: 8px 12px;
  background-color: var(--bg-tertiary);
  border: none;
  color: var(--text-secondary);
  font-size: 12px;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.accordion-toggle:hover {
  background-color: var(--bg-hover);
  color: var(--text-primary);
}

.accordion-content {
  padding: 12px;
  background-color: var(--bg-primary);
  font-size: 13px;
  display: none;
}
.accordion-content.show {
  display: block;
}

.solution-box {
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  padding: 12px;
  margin-top: 8px;
  border-left: 3px solid var(--accent-primary);
}

.solution-box pre {
  margin: 8px 0;
  padding: 10px;
  background: var(--bg-primary);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  overflow-x: auto;
}

.explanation-text {
  font-size: 12px;
  color: var(--text-secondary);
  margin-top: 8px;
  line-height: 1.5;
}

.question-card-footer {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
  margin-top: 4px;
}

.pagination-bar {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 16px;
  margin: 24px 0;
}

/* ==========================================================================
   TAB 3: Live Playground
   ========================================================================== */

.playground-container {
  display: flex;
  flex-direction: column;
  flex: 1;
  height: calc(100vh - var(--header-height));
  overflow: hidden;
}

.playground-topbar {
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  padding: 10px 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-shrink: 0;
  gap: 16px;
}

.engine-selector {
  display: flex;
  gap: 8px;
}

.engine-tab {
  padding: 6px 14px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  background-color: var(--bg-tertiary);
  color: var(--text-secondary);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
}

.engine-tab.active {
  background-color: var(--accent-subtle);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

.playground-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.playground-layout {
  display: flex;
  flex: 1;
  overflow: hidden;
}

.playground-main-pane {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  border-right: 1px solid var(--border-color);
}

.editor-card {
  height: 45%;
  min-height: 180px;
  display: flex;
  flex-direction: column;
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
}

.editor-header {
  padding: 8px 14px;
  background-color: var(--bg-tertiary);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.editor-title {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
}

.editor-tools {
  display: flex;
  align-items: center;
  gap: 8px;
}

.editor-wrapper {
  flex: 1;
  position: relative;
}

.editor-wrapper textarea {
  width: 100%;
  height: 100%;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  border: none;
  padding: 14px;
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1.5;
  resize: none;
  outline: none;
}

.results-card {
  flex: 1;
  display: flex;
  flex-direction: column;
  background-color: var(--bg-primary);
  overflow: hidden;
}

.results-header {
  padding: 8px 14px;
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.results-meta {
  display: flex;
  align-items: center;
  gap: 10px;
}

.meta-label {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
}

.meta-timing {
  font-size: 11px;
  color: var(--text-muted);
}

.results-body {
  flex: 1;
  overflow: auto;
  padding: 12px;
}

/* Result Table Styles */
.results-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 12px;
  font-family: var(--font-mono);
}

.results-table th, .results-table td {
  border: 1px solid var(--border-color);
  padding: 6px 10px;
  text-align: left;
}

.results-table th {
  background-color: var(--bg-tertiary);
  color: var(--accent-primary);
  position: sticky;
  top: 0;
}

.results-table tr:hover {
  background-color: var(--bg-hover);
}

.results-success-msg {
  padding: 12px;
  background-color: var(--success-subtle);
  border: 1px solid var(--success-color);
  border-radius: var(--radius-md);
  color: var(--success-color);
  font-size: 13px;
  margin-bottom: 10px;
}

.results-error-msg {
  padding: 12px;
  background-color: var(--danger-subtle);
  border: 1px solid var(--danger-color);
  border-radius: var(--radius-md);
  color: var(--danger-color);
  font-size: 13px;
  font-family: var(--font-mono);
  margin-bottom: 10px;
}

.schema-sidebar {
  width: 300px;
  background-color: var(--bg-secondary);
  padding: 16px;
  overflow-y: auto;
  flex-shrink: 0;
}

.schema-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 4px;
}

.schema-header h3 {
  font-size: 14px;
  font-weight: 600;
}

.schema-note {
  font-size: 11px;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.schema-table-card {
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  margin-bottom: 10px;
  overflow: hidden;
}

.schema-table-head {
  padding: 8px 12px;
  background-color: var(--bg-hover);
  font-weight: 600;
  font-size: 12px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
}

.schema-table-head:hover {
  color: var(--accent-primary);
}

.schema-cols-list {
  padding: 8px 12px;
  font-size: 11px;
  font-family: var(--font-mono);
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.schema-col-item {
  display: flex;
  justify-content: space-between;
  color: var(--text-secondary);
}

.schema-col-item .pk-tag {
  color: #ffb800;
  font-weight: 700;
  margin-left: 4px;
}

/* ==========================================================================
   TAB 4: Visual Learning Lab
   ========================================================================== */

.visual-container {
  padding: 20px 24px;
  max-width: 1200px;
  margin: 0 auto;
  width: 100%;
}

.visual-tabs-nav {
  display: flex;
  gap: 8px;
  margin-bottom: 20px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 8px;
  overflow-x: auto;
}

.vtab-btn {
  padding: 8px 16px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
}

.vtab-btn.active {
  background-color: var(--accent-subtle);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

.vtab-panel {
  display: none;
}
.vtab-panel.active {
  display: block;
}

.panel-intro {
  margin-bottom: 20px;
}
.panel-intro h3 { font-size: 20px; margin-bottom: 6px; }
.panel-intro p { color: var(--text-secondary); font-size: 14px; }

/* Pipeline Simulator Styles */
.pipeline-stepper-controls {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 20px;
  background-color: var(--bg-secondary);
  padding: 12px 16px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
}

.pipeline-step-indicator {
  flex: 1;
  text-align: center;
  font-size: 14px;
}

.pipeline-track {
  display: flex;
  gap: 6px;
  margin-bottom: 24px;
  overflow-x: auto;
  padding: 4px 0;
}

.pipeline-node {
  flex: 1;
  min-width: 120px;
  padding: 10px 8px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  text-align: center;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.2s;
}

.pipeline-node.active {
  background-color: var(--accent-primary);
  border-color: var(--accent-primary);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 4px 10px rgba(56, 139, 253, 0.3);
}

.pipeline-node.completed {
  border-color: var(--success-color);
  color: var(--success-color);
}

.pipeline-active-detail {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 20px;
}

.pipeline-flow-diagram {
  display: flex;
  align-items: center;
  gap: 16px;
  margin: 16px 0;
  padding: 16px;
  background-color: var(--bg-tertiary);
  border-radius: var(--radius-md);
}

.flow-box {
  flex: 1;
  padding: 12px;
  background-color: var(--bg-primary);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  text-align: center;
}
.flow-arrow {
  font-size: 20px;
  color: var(--accent-primary);
}

/* 3VL Matrix Styles */
.logic-calc-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.logic-inputs-row {
  display: flex;
  gap: 12px;
  margin: 16px 0;
}

.logic-inputs-row .input-box {
  flex: 1;
}

.logic-result-display {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  padding: 20px;
  background-color: var(--bg-tertiary);
  border-radius: var(--radius-md);
  margin: 16px 0;
}

.result-formula {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 600;
}

.result-badge {
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  font-size: 14px;
  font-weight: 700;
  font-family: var(--font-mono);
}
.result-badge.true { background: var(--success-subtle); color: var(--success-color); border: 1px solid var(--success-color); }
.result-badge.false { background: var(--danger-subtle); color: var(--danger-color); border: 1px solid var(--danger-color); }
.result-badge.unknown { background: var(--warning-subtle); color: var(--warning-color); border: 1px solid var(--warning-color); }

.tables-tabs {
  display: flex;
  gap: 6px;
  margin-bottom: 12px;
}
.tt-tab {
  padding: 4px 10px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-size: 12px;
  cursor: pointer;
}
.tt-tab.active {
  background: var(--accent-primary);
  color: #fff;
  border-color: var(--accent-primary);
}

/* Joins Explorer Styles */
.joins-explorer-layout {
  display: flex;
  gap: 20px;
}

.joins-selector-sidebar {
  width: 220px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  flex-shrink: 0;
}

.join-type-btn {
  padding: 10px 14px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  text-align: left;
}
.join-type-btn.active {
  background-color: var(--accent-subtle);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

.joins-details-view {
  flex: 1;
}

/* Normalization Assistant Styles */
.norm-assistant-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.preset-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}

.form-group {
  margin-bottom: 12px;
}
.form-group label {
  display: block;
  font-size: 12px;
  color: var(--text-secondary);
  margin-bottom: 4px;
}
.form-group input, .form-group textarea {
  width: 100%;
}

/* ==========================================================================
   TAB 5: MCQ Arena
   ========================================================================== */

.mcq-container {
  padding: 20px 24px;
  max-width: 900px;
  margin: 0 auto;
  width: 100%;
}

.mcq-topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.mcq-scoreboard {
  display: flex;
  align-items: center;
  gap: 8px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 6px 12px;
  border-radius: var(--radius-lg);
}

.score-pill {
  font-size: 12px;
  padding: 2px 6px;
}

.text-success { color: var(--success-color); }
.text-warning { color: var(--warning-color); }
.text-danger { color: var(--danger-color); }

.mcq-card {
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.mcq-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.mcq-counter-text {
  font-size: 12px;
  color: var(--text-muted);
}

.mcq-question-text {
  font-size: 17px;
  font-weight: 600;
  line-height: 1.5;
  color: var(--text-primary);
}

.mcq-options-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.mcq-option-btn {
  padding: 14px 18px;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 14px;
  text-align: left;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 12px;
  transition: all 0.15s ease;
}

.mcq-option-btn:hover:not(:disabled) {
  background-color: var(--bg-hover);
  border-color: var(--border-focus);
}

.mcq-option-btn:disabled {
  cursor: default;
}
.mcq-option-btn:disabled:not(.correct):not(.wrong) {
  opacity: 0.65;
}

.mcq-option-letter {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 12px;
  flex-shrink: 0;
}

.mcq-option-btn.correct {
  background-color: var(--success-subtle);
  border-color: var(--success-color);
  color: var(--text-primary);
  font-weight: 600;
  box-shadow: 0 0 12px rgba(34, 197, 94, 0.2);
}
.mcq-option-btn.correct .mcq-option-letter {
  background-color: var(--success-color);
  color: #fff;
  border-color: transparent;
}

.mcq-option-btn.wrong {
  background-color: var(--danger-subtle);
  border-color: var(--danger-color);
  color: var(--text-primary);
  box-shadow: 0 0 12px rgba(239, 68, 68, 0.2);
}
.mcq-option-btn.wrong .mcq-option-letter {
  background-color: var(--danger-color);
  color: #fff;
  border-color: transparent;
}

.mcq-feedback-box {
  padding: 16px;
  border-radius: var(--radius-md);
  background-color: var(--bg-tertiary);
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.mcq-feedback-box.hidden {
  display: none;
}

.trap-warning-box {
  display: flex;
  gap: 10px;
  background-color: #2b1d00;
  border-left: 4px solid #ffb800;
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  color: #ffd875;
  font-size: 13px;
}

.explanation-box {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.6;
}

.mcq-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 8px;
}

/* ==========================================================================
   TAB 6: Exam Hall
   ========================================================================== */

.exam-container {
  padding: 24px;
  max-width: 1200px;
  margin: 0 auto;
  width: 100%;
}

.exam-screen {
  display: none;
}
.exam-screen.active {
  display: block;
}

.exam-hero {
  text-align: center;
  padding: 36px 20px;
}

.exam-hero h2 {
  font-size: 26px;
  margin-bottom: 8px;
}

.exam-hero p {
  color: var(--text-secondary);
  font-size: 15px;
  margin-bottom: 30px;
}

.exam-modes-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  text-align: left;
}

.exam-mode-card {
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  position: relative;
}

.exam-mode-card.featured {
  border-color: var(--accent-primary);
  background-color: var(--bg-elevated);
}

.mode-badge {
  display: inline-block;
  padding: 3px 8px;
  border-radius: var(--radius-pill);
  font-size: 11px;
  font-weight: 700;
  align-self: flex-start;
  background: var(--bg-hover);
  color: var(--text-secondary);
}
.mode-badge.popular {
  background: var(--accent-primary);
  color: #fff;
}
.mode-badge.hardcore {
  background: #7928ca;
  color: #fff;
}

.mode-specs {
  display: flex;
  gap: 12px;
  font-size: 12px;
  color: var(--text-muted);
  margin-top: auto;
}

/* Active Exam Layout */
.exam-active-layout {
  display: flex;
  gap: 20px;
}

.exam-main-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.exam-live-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 14px;
}

.exam-timer-display {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  background-color: var(--danger-subtle);
  border: 1px solid var(--danger-color);
  color: var(--danger-color);
  border-radius: var(--radius-pill);
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 700;
}

.exam-live-options {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin: 16px 0;
}

.exam-option-item {
  width: 100%;
  padding: 14px 18px;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 14px;
  text-align: left;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 12px;
  transition: all 0.15s ease;
}
.exam-option-item:hover {
  background-color: var(--bg-hover);
  border-color: var(--border-focus);
}
.exam-option-item.selected {
  background-color: var(--accent-subtle);
  border-color: var(--accent-primary);
  color: var(--text-primary);
  font-weight: 600;
  box-shadow: 0 0 12px rgba(59, 130, 246, 0.25);
}

.exam-actions-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-top: 1px solid var(--border-color);
  padding-top: 16px;
}

.exam-nav-btns {
  display: flex;
  gap: 10px;
}

.exam-palette-sidebar {
  width: 280px;
  flex-shrink: 0;
}

.palette-legend {
  display: flex;
  gap: 10px;
  font-size: 11px;
  color: var(--text-muted);
  margin: 10px 0 14px 0;
}

.legend-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: inline-block;
}
.legend-dot.answered { background: var(--success-color); }
.legend-dot.flagged { background: #ffb800; }
.legend-dot.unvisited { background: var(--bg-tertiary); border: 1px solid var(--border-color); }

.palette-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 8px;
  max-height: 400px;
  overflow-y: auto;
}

.palette-btn {
  aspect-ratio: 1;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  border-radius: var(--radius-sm);
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
}
.palette-btn.current {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 2px var(--accent-primary);
}
.palette-btn.answered {
  background-color: var(--success-color);
  color: #fff;
  border-color: var(--success-color);
}
.palette-btn.flagged {
  background-color: #ffb800;
  color: #000;
  border-color: #ffb800;
}

/* Scorecard Results Styles */
.scorecard-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
}

.scorecard-stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}

.stat-card {
  padding: 16px;
  background-color: var(--bg-tertiary);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  text-align: center;
}
.stat-card .label { font-size: 12px; color: var(--text-muted); display: block; margin-bottom: 4px; }
.stat-card strong { font-size: 22px; font-weight: 700; }

.scorecard-diagnosis {
  margin-bottom: 24px;
}

.diagnosis-box {
  padding: 16px;
  background-color: var(--bg-tertiary);
  border-radius: var(--radius-md);
  border-left: 4px solid var(--accent-primary);
  font-size: 13px;
  line-height: 1.6;
}

.scorecard-review-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-top: 14px;
}

/* Toast Notifications */
.toast-container {
  position: fixed;
  bottom: 20px;
  right: 20px;
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.toast {
  padding: 12px 18px;
  background-color: var(--bg-elevated);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 13px;
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: center;
  gap: 10px;
  animation: slideIn 0.2s ease-out;
}
.toast.success { border-color: var(--success-color); }
.toast.error { border-color: var(--danger-color); }

@keyframes slideIn {
  from { transform: translateX(100%); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}

@keyframes pulse {
  0% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.04); opacity: 0.85; }
  100% { transform: scale(1); opacity: 1; }
}

.highlight-glow {
  box-shadow: 0 0 0 3px var(--accent-primary), 0 0 24px rgba(56, 139, 253, 0.45) !important;
  transition: box-shadow 0.3s ease;
}

.markdown-list {
  margin: 8px 0 12px 20px;
  padding-left: 8px;
}

.markdown-list li {
  margin-bottom: 6px;
  line-height: 1.6;
}

.bullet-item {
  list-style-type: disc;
}

.numbered-item {
  list-style-type: none;
}

/* ==========================================================================
   Responsive Mobile Adjustments
   ========================================================================== */

@media (max-width: 1024px) {
  .playground-layout {
    flex-direction: column;
  }
  .schema-sidebar {
    width: 100%;
    max-height: 340px;
    overflow-y: auto;
  }
  .study-container {
    flex-direction: column;
    height: auto;
  }
  .study-sidebar {
    width: 100%;
    max-height: 340px;
    overflow-y: auto;
  }
  .exam-active-layout {
    grid-template-columns: 1fr;
    flex-direction: column;
  }
  .exam-palette-sidebar {
    width: 100%;
  }
}

@media (max-width: 768px) {
  .app-header {
    flex-wrap: wrap;
    height: auto;
    padding: 10px 14px;
    gap: 8px;
  }
  .header-left {
    width: auto;
    max-width: calc(100% - 210px);
    justify-content: flex-start;
  }
  .logo-text .subtitle {
    display: none;
  }
  .header-right {
    position: static;
    display: flex;
    align-items: center;
    gap: 8px;
    margin-left: auto;
  }
  .header-shortcuts-badge {
    display: none;
  }
  .main-nav {
    order: 3;
    width: 100%;
    margin-top: 4px;
    padding-bottom: 6px;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }
  .nav-tab {
    min-height: 44px;
    padding: 8px 12px;
    font-size: 12px;
  }
  .filter-controls-row {
    flex-direction: column;
    align-items: stretch;
    gap: 8px;
  }
  .filter-controls-row .form-select,
  .search-box.practice-search {
    width: 100%;
    min-width: 0;
  }
  .logic-calc-grid, 
  .norm-assistant-grid, 
  .joins-explorer-layout {
    grid-template-columns: 1fr;
    flex-direction: column;
    gap: 16px;
  }
  .joins-selector-sidebar {
    display: flex;
    overflow-x: auto;
    white-space: nowrap;
    gap: 8px;
    padding-bottom: 6px;
    width: 100%;
  }
  .join-type-btn {
    min-width: 140px;
  }
  .mcq-topbar {
    flex-direction: column;
    align-items: stretch;
    gap: 12px;
  }
  .mcq-scoreboard {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    width: 100%;
    gap: 8px;
  }
  .mcq-card-footer,
  .exam-actions-bar {
    flex-wrap: wrap;
    gap: 10px;
  }
  .exam-modes-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .logo-text h1 {
    font-size: 15px;
  }
  .btn {
    min-height: 44px;
  }
  .screenshot-btn .btn-text {
    display: none;
  }
  .db-status-pill .status-text {
    display: none;
  }
  .scorecard-stats-grid {
    grid-template-columns: 1fr 1fr;
    gap: 8px;
  }
}

/* ==========================================================================
   Day 6 Cheatsheet, Hands-on Scenarios & Multi-Select MCQ Enhancements
   ========================================================================== */

/* Hands-on Scenarios Filter Pill */
.filter-pill.handson-pill {
  background: linear-gradient(135deg, rgba(255, 170, 0, 0.15), rgba(255, 110, 0, 0.15));
  border-color: #f59f00;
  color: #ffc038;
  font-weight: 600;
}
.filter-pill.handson-pill.active {
  background: linear-gradient(135deg, #f59f00, #e67700);
  color: #000;
  border-color: #f59f00;
}

/* Scenario Schema Selector in Playground Topbar */
.schema-selector-group {
  display: flex;
  align-items: center;
  gap: 8px;
}
.schema-select-label {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
}
.schema-dropdown {
  background-color: var(--bg-tertiary);
  border: 1px solid var(--accent-primary);
  color: var(--accent-primary);
  font-weight: 600;
  padding: 5px 10px;
  border-radius: var(--radius-sm);
  font-size: 12px;
}

/* Multi-Select MCQ Styles */
.mcq-option-btn.multi-option {
  cursor: pointer;
  user-select: none;
  position: relative;
}
.mcq-option-btn.multi-option.selected {
  background-color: var(--accent-subtle);
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 1px var(--accent-primary);
}
.mcq-option-btn.multi-option.selected .mcq-option-letter {
  background-color: var(--accent-primary);
  color: #fff;
  border-color: var(--accent-primary);
}
.mcq-multi-action-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  background-color: var(--bg-tertiary);
  border: 1px dashed var(--border-color);
  border-radius: var(--radius-md);
  margin-top: 6px;
  margin-bottom: 8px;
  gap: 12px;
}
.mcq-multi-action-bar.hidden {
  display: none;
}
.mcq-multi-hint {
  font-size: 13px;
  color: var(--text-secondary);
  font-weight: 500;
}

/* Hands-on Scenario Badges */
.badge-scenario {
  background-color: rgba(56, 139, 253, 0.2);
  border: 1px solid #388bfd;
  color: #79c0ff;
  font-weight: 600;
  font-size: 11px;
}
.badge-marks {
  background-color: rgba(230, 119, 0, 0.2);
  border: 1px solid #f59f00;
  color: #ffc038;
  font-weight: 700;
  font-size: 11px;
}

/* Hands-on Verification Widget */
.handson-verify-box {
  margin-top: 12px;
  padding: 14px;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.handson-verify-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.handson-verify-header h5 {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-primary);
}
.handson-verify-textarea {
  width: 100%;
  min-height: 85px;
  font-family: var(--font-mono);
  font-size: 12px;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 8px 10px;
  resize: vertical;
}
.handson-verify-textarea:focus {
  outline: none;
  border-color: var(--accent-primary);
}
.handson-verify-actions {
  display: flex;
  gap: 10px;
  align-items: center;
}
.verify-status-banner {
  padding: 12px 16px;
  border-radius: var(--radius-md);
  font-size: 13px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  border-left: 4px solid;
}
.verify-status-banner.pass {
  background-color: var(--success-subtle);
  border-color: var(--success-color);
  color: var(--text-primary);
}
.verify-status-banner.pass strong {
  color: var(--success-color);
  font-size: 14px;
}
.verify-status-banner.fail {
  background-color: var(--danger-subtle);
  border-color: var(--danger-color);
  color: var(--text-primary);
}
.verify-status-banner.fail strong {
  color: var(--danger-color);
  font-size: 14px;
}
.verify-status-banner.info {
  background-color: var(--accent-subtle);
  border-color: var(--accent-primary);
  color: var(--text-primary);
}
.verify-status-banner.info strong {
  color: var(--accent-primary);
  font-size: 14px;
}

/* Expected Output Table Preview */
.expected-table-container {
  max-height: 220px;
  overflow: auto;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  margin-top: 8px;
}
.expected-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 11px;
  font-family: var(--font-mono);
}
.expected-table th, .expected-table td {
  border: 1px solid var(--border-color);
  padding: 4px 8px;
  text-align: left;
}
.expected-table th {
  background-color: var(--bg-hover);
  color: var(--accent-primary);
  position: sticky;
  top: 0;
}

/* Day 6 Cheatsheet Top 20 Traps Cards */
.cs-traps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(360px, 1fr));
  gap: 14px;
  margin-top: 14px;
}
.cs-trap-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-left: 4px solid #f59f00;
  border-radius: var(--radius-md);
  padding: 14px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  transition: transform 0.15s ease;
}
.cs-trap-card:hover {
  transform: translateY(-2px);
  border-color: #f59f00;
}
.cs-trap-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.cs-trap-num {
  font-weight: 700;
  font-size: 12px;
  color: #ffc038;
}
.cs-trap-title {
  font-weight: 600;
  font-size: 14px;
  color: var(--text-primary);
}
.cs-trap-rule {
  font-family: var(--font-mono);
  font-size: 12px;
  background-color: var(--bg-tertiary);
  padding: 6px 10px;
  border-radius: var(--radius-sm);
  color: #ff7b72;
  border-left: 3px solid #ff7b72;
}
.cs-trap-explanation {
  font-size: 12px;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* 21-Step Decision Matrix Table */
.matrix-table-container {
  overflow-x: auto;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  margin-top: 14px;
}
.decision-matrix-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 12px;
}
.decision-matrix-table th, .decision-matrix-table td {
  border: 1px solid var(--border-color);
  padding: 8px 12px;
  text-align: left;
}
.decision-matrix-table th {
  background-color: var(--bg-hover);
  color: var(--text-primary);
  font-weight: 600;
}
.decision-matrix-table tr:hover {
  background-color: var(--bg-tertiary);
}
.clause-badge {
  display: inline-block;
  padding: 2px 6px;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  background-color: var(--accent-subtle);
  color: var(--accent-primary);
}