/* ==========================================================================
   Stripe-Inspired Clean & Flat Design System
   Rules: No gradients, no glassmorphism, no purple/pink, no glowing effects
   ========================================================================== */

:root {
  /* Light Theme Palette */
  --bg-app: #f8fafc;
  --bg-surface: #ffffff;
  --bg-surface-secondary: #f1f5f9;
  --bg-surface-hover: #f8fafc;
  
  --border-color: #e2e8f0;
  --border-color-subtle: #edf2f7;
  --border-color-focus: #0066cc;

  --text-main: #0a2540;
  --text-muted: #475569;
  --text-subtle: #64748b;
  --text-inverted: #ffffff;

  /* Primary Brand (Stripe Navy / Slate Blue) */
  --primary: #0a2540;
  --primary-hover: #1e3a8a;
  --primary-bg: #e2e8f0;
  --primary-text: #ffffff;

  /* Semantic Colors */
  --success: #059669;
  --success-bg: #ecfdf5;
  --success-border: #a7f3d0;
  --success-text: #065f46;

  --danger: #dc2626;
  --danger-bg: #fef2f2;
  --danger-border: #fecaca;
  --danger-text: #991b1b;

  --warning: #d97706;
  --warning-bg: #fffbeb;
  --warning-border: #fde68a;

  /* UI Tokens */
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --shadow-flat: 0 1px 2px rgba(0, 0, 0, 0.04);
}

/* Dark Theme Palette */
body.dark-theme {
  --bg-app: #0b0f19;
  --bg-surface: #131b2e;
  --bg-surface-secondary: #1e293b;
  --bg-surface-hover: #182238;
  
  --border-color: #243048;
  --border-color-subtle: #1c263b;
  --border-color-focus: #3b82f6;

  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-subtle: #64748b;
  --text-inverted: #0b0f19;

  --primary: #3b82f6;
  --primary-hover: #2563eb;
  --primary-bg: #1e293b;
  --primary-text: #ffffff;

  --success: #10b981;
  --success-bg: #064e3b;
  --success-border: #047857;
  --success-text: #d1fae5;

  --danger: #ef4444;
  --danger-bg: #7f1d1d;
  --danger-border: #991b1b;
  --danger-text: #fee2e2;

  --shadow-flat: 0 1px 2px rgba(0, 0, 0, 0.2);
}

/* Base Reset */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

/* Header */
.app-header {
  background-color: var(--bg-surface);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 20px;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

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

.brand-logo {
  width: 32px;
  height: 32px;
  background-color: var(--primary);
  color: var(--primary-text);
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
}

.brand-info {
  display: flex;
  align-items: center;
  gap: 8px;
}

.brand-title {
  font-weight: 700;
  font-size: 15px;
  letter-spacing: -0.01em;
  color: var(--text-main);
}

.brand-badge {
  font-size: 11px;
  font-weight: 600;
  background-color: var(--bg-surface-secondary);
  color: var(--text-subtle);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
}

/* Nav Tabs */
.nav-tabs {
  display: flex;
  gap: 4px;
  background-color: var(--bg-surface-secondary);
  padding: 3px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.nav-tab {
  background: transparent;
  border: none;
  font-family: inherit;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  padding: 6px 14px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background-color 0.15s, color 0.15s;
}

.nav-tab:hover {
  color: var(--text-main);
}

.nav-tab.active {
  background-color: var(--bg-surface);
  color: var(--text-main);
  box-shadow: var(--shadow-flat);
}

/* Layout Container */
.main-container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 24px 20px 60px 20px;
}

.tab-content {
  display: none;
}

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

/* Card Component */
.card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-flat);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  font-family: inherit;
  font-size: 14px;
  font-weight: 600;
  padding: 9px 16px;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.15s ease;
  line-height: 1.2;
}

.btn-primary {
  background-color: var(--primary);
  color: var(--primary-text);
  border-color: var(--primary);
}

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

.btn-secondary {
  background-color: var(--bg-surface);
  color: var(--text-main);
  border-color: var(--border-color);
}

.btn-secondary:hover {
  background-color: var(--bg-surface-secondary);
  border-color: var(--border-color);
}

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

.btn-danger:hover {
  background-color: #b91c1c;
  border-color: #b91c1c;
}

.btn-sm {
  font-size: 12px;
  padding: 6px 10px;
}

.btn-icon {
  padding: 7px;
}

/* Badges */
.badge {
  display: inline-flex;
  align-items: center;
  font-size: 12px;
  font-weight: 600;
  padding: 3px 8px;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
}

.badge-primary {
  background-color: var(--bg-surface-secondary);
  color: var(--text-main);
  border-color: var(--border-color);
}

.badge-neutral {
  background-color: var(--bg-surface-secondary);
  color: var(--text-subtle);
  border-color: var(--border-color);
}

.badge-success {
  background-color: var(--success-bg);
  color: var(--success-text);
  border-color: var(--success-border);
}

.badge-danger {
  background-color: var(--danger-bg);
  color: var(--danger-text);
  border-color: var(--danger-border);
}

/* Form Controls */
.form-input, .form-select, .form-select-sm {
  font-family: inherit;
  font-size: 14px;
  background-color: var(--bg-surface);
  color: var(--text-main);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 8px 12px;
  outline: none;
  transition: border-color 0.15s;
}

.form-select-sm {
  font-size: 12px;
  padding: 4px 8px;
}

.form-input:focus, .form-select:focus, .form-select-sm:focus {
  border-color: var(--border-color-focus);
}

/* Control Panel / Filter Pills */
.control-panel {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 12px;
}

.category-filters {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
}

.filter-pill {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  font-family: inherit;
  font-size: 12px;
  font-weight: 600;
  padding: 6px 12px;
  border-radius: 9999px;
  cursor: pointer;
  transition: all 0.15s;
}

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

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

.filter-pill-danger {
  border-color: var(--danger-border);
  color: var(--danger-text);
}

.filter-pill-danger.active {
  background-color: var(--danger);
  border-color: var(--danger);
  color: #ffffff;
}

.dot-danger {
  display: inline-block;
  width: 6px;
  height: 6px;
  background-color: var(--danger);
  border-radius: 50%;
  margin-right: 4px;
}

.filter-pill-danger.active .dot-danger {
  background-color: #ffffff;
}

.filter-pill-unanswered {
  border-color: var(--border-color);
  color: var(--text-main);
  background-color: var(--bg-surface);
}

.filter-pill-unanswered.active {
  background-color: var(--primary);
  border-color: var(--primary);
  color: var(--primary-text);
}

.dot-unanswered {
  display: inline-block;
  width: 6px;
  height: 6px;
  background-color: var(--primary);
  border-radius: 50%;
  margin-right: 4px;
}

.filter-pill-unanswered.active .dot-unanswered {
  background-color: #ffffff;
}

.quiz-utility-tools {
  display: flex;
  align-items: center;
  gap: 10px;
}

.jump-box {
  display: flex;
  align-items: center;
  gap: 6px;
}

/* Progress Bar */
.progress-bar-container {
  width: 100%;
  height: 4px;
  background-color: var(--border-color);
  border-radius: 2px;
  overflow: hidden;
  margin-bottom: 16px;
}

.progress-bar-fill {
  height: 100%;
  background-color: var(--primary);
  transition: width 0.25s ease;
}

/* Quiz Card */
.quiz-card {
  padding: 24px;
}

.quiz-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-color-subtle);
  margin-bottom: 20px;
}

.meta-left {
  display: flex;
  align-items: center;
  gap: 8px;
}

.meta-right {
  display: flex;
  align-items: center;
  gap: 6px;
}

.question-body {
  margin-bottom: 24px;
}

.question-text {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-main);
  line-height: 1.5;
  margin-bottom: 16px;
}

.question-image-wrapper {
  margin: 16px 0;
  padding: 12px;
  background-color: var(--bg-surface-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  text-align: center;
}

.question-image-wrapper img {
  max-width: 100%;
  max-height: 280px;
  object-fit: contain;
  display: inline-block;
}

/* Options */
.options-grid {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 24px;
}

.option-card {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px 16px;
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.15s;
  text-align: left;
  user-select: none;
}

.option-card:hover:not(.locked) {
  background-color: var(--bg-surface-hover);
  border-color: var(--text-subtle);
}

.option-key {
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--bg-surface-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  font-size: 12px;
  font-weight: 700;
  color: var(--text-muted);
  flex-shrink: 0;
  margin-top: 1px;
}

.option-text {
  font-size: 15px;
  color: var(--text-main);
  line-height: 1.4;
  flex-grow: 1;
}

/* Selected option (prior to submit) */
.option-card.selected {
  border-color: var(--primary);
  background-color: var(--bg-surface-secondary);
}

.option-card.selected .option-key {
  background-color: var(--primary);
  border-color: var(--primary);
  color: var(--primary-text);
}

/* Correct state */
.option-card.correct {
  border-color: var(--success) !important;
  background-color: var(--success-bg) !important;
}

.option-card.correct .option-key {
  background-color: var(--success) !important;
  border-color: var(--success) !important;
  color: #ffffff !important;
}

.option-card.correct .option-text {
  color: var(--success-text) !important;
  font-weight: 600;
}

/* Wrong state */
.option-card.wrong {
  border-color: var(--danger) !important;
  background-color: var(--danger-bg) !important;
}

.option-card.wrong .option-key {
  background-color: var(--danger) !important;
  border-color: var(--danger) !important;
  color: #ffffff !important;
}

.option-card.wrong .option-text {
  color: var(--danger-text) !important;
}

/* Dim others */
.option-card.dimmed {
  opacity: 0.5;
  cursor: default;
}

/* Feedback Banner */
.feedback-banner {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px 16px;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  margin-bottom: 24px;
}

.feedback-banner.success {
  background-color: var(--success-bg);
  border-color: var(--success-border);
  color: var(--success-text);
}

.feedback-banner.danger {
  background-color: var(--danger-bg);
  border-color: var(--danger-border);
  color: var(--danger-text);
}

.feedback-title {
  font-weight: 700;
  font-size: 14px;
  margin-bottom: 2px;
}

.feedback-desc {
  font-size: 13px;
  line-height: 1.4;
}

/* Quiz Card Footer */
.quiz-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 16px;
  border-top: 1px solid var(--border-color-subtle);
}

.counter-text {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-subtle);
}

/* Analytics Tab */
.analytics-header, .bank-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 24px;
}

.page-title {
  font-size: 22px;
  font-weight: 700;
  color: var(--text-main);
  letter-spacing: -0.01em;
  margin-bottom: 4px;
}

.page-subtitle {
  font-size: 14px;
  color: var(--text-subtle);
}

.analytics-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

/* Stats Grid */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}

.stat-card {
  padding: 20px;
}

.stat-label {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-subtle);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 8px;
}

.stat-value {
  font-size: 32px;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1;
  margin-bottom: 6px;
}

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

/* Section Cards */
.section-card {
  padding: 20px;
  margin-bottom: 24px;
}

.section-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}

.section-title {
  font-size: 16px;
  font-weight: 700;
  color: var(--text-main);
}

.section-subtitle {
  font-size: 13px;
  color: var(--text-subtle);
  margin-top: 2px;
}

/* Category Breakdown Bars */
.category-breakdown {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.cat-bar-item {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.cat-bar-header {
  display: flex;
  justify-content: space-between;
  font-size: 13px;
}

.cat-bar-title {
  font-weight: 600;
  color: var(--text-main);
}

.cat-bar-stats {
  color: var(--text-subtle);
}

.cat-progress-track {
  width: 100%;
  height: 8px;
  background-color: var(--bg-surface-secondary);
  border-radius: 4px;
  overflow: hidden;
  border: 1px solid var(--border-color);
}

.cat-progress-fill {
  height: 100%;
  background-color: var(--primary);
  border-radius: 4px;
  transition: width 0.3s;
}

/* Data Table */
.table-responsive {
  width: 100%;
  overflow-x: auto;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
  text-align: left;
}

.data-table th {
  padding: 10px 12px;
  font-weight: 600;
  color: var(--text-subtle);
  border-bottom: 1px solid var(--border-color);
  background-color: var(--bg-surface-secondary);
}

.data-table td {
  padding: 12px;
  border-bottom: 1px solid var(--border-color-subtle);
  color: var(--text-main);
  vertical-align: middle;
}

.data-table tr:hover td {
  background-color: var(--bg-surface-hover);
}

/* Empty state */
.empty-state {
  padding: 40px 20px;
  text-align: center;
  color: var(--text-subtle);
}

.empty-state svg {
  margin-bottom: 8px;
  color: var(--text-subtle);
}

.empty-state-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 4px;
}

.empty-state-desc {
  font-size: 13px;
}

/* Bank Filters Card */
.bank-filters-card {
  padding: 16px;
  margin-bottom: 16px;
}

.bank-filters-grid {
  display: grid;
  grid-template-columns: 2fr 1.5fr 1.5fr;
  gap: 12px;
}

@media (max-width: 768px) {
  .bank-filters-grid {
    grid-template-columns: 1fr;
  }
}

.bank-questions-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.bank-item-card {
  padding: 16px;
  cursor: pointer;
  transition: border-color 0.15s;
}

.bank-item-card:hover {
  border-color: var(--text-subtle);
}

.bank-item-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}

.bank-item-text {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-main);
}

.bank-item-details {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--border-color-subtle);
}

.bank-options-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-top: 8px;
}

.bank-option-row {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  padding: 6px 10px;
  border-radius: var(--radius-sm);
  background-color: var(--bg-surface-secondary);
}

.bank-option-row.is-correct {
  background-color: var(--success-bg);
  color: var(--success-text);
  font-weight: 600;
}

/* Utility Helpers */
.hidden {
  display: none !important;
}

.text-success {
  color: var(--success) !important;
}

.text-danger {
  color: var(--danger) !important;
}

.text-subtle {
  color: var(--text-subtle);
  font-size: 12px;
}