/* ═══════════════════════════════════════════════════════════
   Erikson Study App - Modern Theme with Light/Dark Mode
   ═══════════════════════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;500;600;700;800&family=JetBrains+Mono:wght@400;500&display=swap');

/* ─── Light Mode (Default) ─────────────────────────────────── */
:root {
  /* Core palette - clean light theme */
  --bg: #f8f9fb;
  --bg-elevated: #ffffff;
  --panel: #ffffff;
  --panel-hover: #f3f4f6;

  /* Text hierarchy - WCAG AA compliant (4.5:1 min contrast) */
  --text: #1f2937;
  --text-secondary: #4b5563;  /* 7:1 contrast on white */
  --text-muted: #6b7280;      /* 5.3:1 contrast on white */

  /* Accent colors */
  --accent: #3b82f6;
  --accent-glow: rgba(59, 130, 246, 0.1);
  --accent-strong: #2563eb;

  /* Semantic colors */
  --success: #10b981;
  --success-glow: rgba(16, 185, 129, 0.1);
  --success-strong: #059669;

  --warning: #f59e0b;
  --warning-glow: rgba(245, 158, 11, 0.1);

  --danger: #ef4444;
  --danger-glow: rgba(239, 68, 68, 0.1);

  /* Legacy aliases (for inline styles) */
  --ok: var(--success);
  --err: var(--danger);
  --bg-panel: var(--panel);
  --fg: var(--text);
  --surface: var(--panel-hover);

  --streak: #f97316;
  --streak-glow: rgba(249, 115, 22, 0.1);

  /* Borders */
  --border: rgba(0, 0, 0, 0.08);
  --border-hover: rgba(0, 0, 0, 0.15);

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.12);

  /* Timing */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
  --transition-slow: 0.4s ease;

  /* Content width for readability */
  --content-width: 720px;
  --container-width: 1000px;
}

/* ─── Dark Mode ────────────────────────────────────────────── */
[data-theme="dark"] {
  /* Core palette - deep midnight with electric accents */
  --bg: #0a0c10;
  --bg-elevated: #12151c;
  --panel: #161a24;
  --panel-hover: #1c212e;

  /* Text hierarchy - WCAG AA compliant */
  --text: #f0f4fc;
  --text-secondary: #b0b8c9;  /* 7.2:1 contrast on #0a0c10 */
  --text-muted: #8b95a8;      /* 4.8:1 contrast on #0a0c10 */

  /* Accent colors */
  --accent: #6c9fff;
  --accent-glow: rgba(108, 159, 255, 0.15);
  --accent-strong: #4d8bff;

  /* Semantic colors */
  --success: #34d399;
  --success-glow: rgba(52, 211, 153, 0.12);
  --success-strong: #10b981;

  --warning: #fbbf24;
  --warning-glow: rgba(251, 191, 36, 0.12);

  --danger: #f87171;
  --danger-glow: rgba(248, 113, 113, 0.12);

  /* Legacy aliases (for inline styles) */
  --ok: var(--success);
  --err: var(--danger);
  --bg-panel: var(--panel);
  --fg: var(--text);
  --surface: var(--panel-hover);

  --streak: #fb923c;
  --streak-glow: rgba(251, 146, 60, 0.15);

  /* Borders */
  --border: rgba(255, 255, 255, 0.06);
  --border-hover: rgba(255, 255, 255, 0.12);

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
}

/* ─── Reset & Base ─────────────────────────────────────────── */
*, *::before, *::after {
  box-sizing: border-box;
}

html, body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Outfit', system-ui, -apple-system, sans-serif;
  font-weight: 400;
  line-height: 1.6;
  margin: 0;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--accent-strong);
}

/* ─── Focus States ─────────────────────────────────────────── */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 8px;
}

/* ─── Layout ───────────────────────────────────────────────── */
.container {
  width: 100%;
  margin: 0 auto;
  padding: 16px 20px;
}

@media (min-width: 1024px) {
  .container {
    max-width: 1000px;
    padding: 24px;
  }
}

.row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

/* ─── Top Bar ──────────────────────────────────────────────── */
.topbar {
  background: var(--panel);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  padding: 8px 0;
}

.topbar .container {
  padding-top: 4px;
  padding-bottom: 4px;
}

.brand {
  flex-shrink: 0;
}

.brand a {
  font-weight: 700;
  font-size: 1.15rem;
  letter-spacing: -0.02em;
  color: var(--text);
  white-space: nowrap;
}

.brand a:hover {
  color: var(--accent);
}

.nav {
  display: flex;
  gap: 4px;
  overflow-x: auto;
  scrollbar-width: none; /* Hide scrollbar Firefox */
  -ms-overflow-style: none; /* Hide scrollbar IE/Edge */
  padding: 4px 0;
  margin: 0 -4px;
  flex: 1 1 100%; /* Take full width on mobile */
  order: 3;
}

.nav::-webkit-scrollbar {
  display: none; /* Hide scrollbar Chrome/Safari */
}

@media (min-width: 768px) {
  .nav {
    flex: none;
    order: unset;
    margin: 0;
  }
}

.nav a {
  padding: 8px 12px;
  border-radius: 10px;
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.85rem;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.nav a:hover {
  color: var(--text);
  background: var(--panel-hover);
}

.nav a.active {
  color: var(--accent);
  background: var(--accent-glow);
}

/* Nav link with badge */
.nav-link-badge {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.nav-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 18px;
  height: 18px;
  padding: 0 5px;
  font-size: 0.7rem;
  font-weight: 700;
  color: #fff;
  background: var(--danger);
  border-radius: 9px;
}

.auth {
  display: flex;
  gap: 8px;
  align-items: center;
  flex-shrink: 0;
}

@media (max-width: 480px) {
  .auth .muted {
    display: none; /* Hide username on very small screens to save space */
  }
}

/* ─── Panels ───────────────────────────────────────────────── */
.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 16px;
  margin: 12px 0;
  transition: border-color var(--transition-fast);
}

@media (min-width: 768px) {
  .panel {
    padding: 24px;
    margin: 16px 0;
  }
}

.panel:hover {
  border-color: var(--border-hover);
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
}

/* ─── Typography ───────────────────────────────────────────── */
.h1 {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  margin: 0 0 8px;
  line-height: 1.2;
}

.h2 {
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin: 0 0 6px;
  line-height: 1.3;
}

@media (min-width: 768px) {
  .h1 { font-size: 2rem; }
  .h2 { font-size: 1.25rem; }
}

.muted {
  color: var(--text-secondary);
}

.text-sm {
  font-size: 0.875rem;
}

/* ─── Buttons ──────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 18px;
  border-radius: 12px;
  background: var(--accent);
  color: var(--bg);
  font-family: inherit;
  font-weight: 600;
  font-size: 0.95rem;
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  touch-action: manipulation;
}

@media (min-width: 768px) {
  .btn {
    padding: 12px 20px;
  }
}

.btn:hover {
  background: var(--accent-strong);
  color: #fff;
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn:active {
  transform: translateY(0);
}

.btn-sm {
  padding: 6px 12px;
  font-size: 0.85rem;
  border-radius: 8px;
}

.btn-lite {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}

.btn-lite:hover {
  background: var(--panel-hover);
  border-color: var(--border-hover);
  color: var(--text);
}

.btn-ok {
  background: var(--success);
  color: var(--bg);
}

.btn-ok:hover {
  background: var(--success-strong);
  color: #fff;
}

.btn-danger {
  background: var(--danger);
  color: var(--bg);
}

.btn-danger:hover {
  background: #ef4444;
  color: #fff;
}

.btn-warn {
  background: var(--warning);
  color: var(--bg);
}

.btn-warn:hover {
  background: #f59e0b;
  color: var(--bg);
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 16px;
  align-items: center;
}

@media (max-width: 480px) {
  .btn-row {
    flex-direction: column;
    align-items: stretch;
  }
  
  .btn-row .btn {
    width: 100%;
  }
}

/* ─── Forms ────────────────────────────────────────────────── */
form p {
  margin: 14px 0;
}

label {
  display: block;
  margin-bottom: 8px;
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
}

input, textarea, select {
  width: 100%;
  padding: 14px 16px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  color: var(--text);
  font-family: inherit;
  font-size: 1rem;
  transition: all var(--transition-fast);
}

input:focus, textarea:focus, select:focus {
  border-color: var(--accent);
  background: rgba(108, 159, 255, 0.05);
  outline: none;
}

/* Style select dropdown options for readability */
select option {
  background: var(--bg-elevated);
  color: var(--text);
  padding: 12px 16px;
}

select option:checked,
select option[selected] {
  background: var(--accent-glow);
  color: var(--accent);
  font-weight: 600;
}

select option:hover {
  background: rgba(108, 159, 255, 0.1);
}

textarea {
  min-height: 200px;
  resize: vertical;
  line-height: 1.6;
}

/* ─── Flash Messages ───────────────────────────────────────── */
.flash {
  padding: 14px 18px;
  border-radius: 12px;
  margin: 12px 0;
  border: 1px solid var(--border);
  background: var(--panel);
  font-weight: 500;
  animation: slideIn 0.3s ease;
}

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

.flash.error {
  border-color: var(--danger);
  background: var(--danger-glow);
  color: var(--danger);
}

.flash.success {
  border-color: var(--success);
  background: var(--success-glow);
  color: var(--success);
}

.flash.warning {
  border-color: var(--warning);
  background: var(--warning-glow);
  color: var(--warning);
}

.flash.info {
  border-color: var(--accent);
  background: var(--accent-glow);
  color: var(--accent);
}

/* ─── Pills & Badges ───────────────────────────────────────── */
.pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.02);
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: 500;
}

/* ─── Done Badge - Satisfying Green ────────────────────────── */
.badge-done {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  border-radius: 999px;
  background: linear-gradient(135deg, var(--success) 0%, #059669 100%);
  color: white;
  font-size: 0.85rem;
  font-weight: 600;
  box-shadow: 0 2px 8px rgba(52, 211, 153, 0.3);
  animation: badgePop 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.badge-done::before {
  content: '✓';
  font-weight: 700;
}

@keyframes badgePop {
  0% { transform: scale(0.8); opacity: 0; }
  50% { transform: scale(1.1); }
  100% { transform: scale(1); opacity: 1; }
}

.badge-pending {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  font-size: 0.85rem;
  font-weight: 500;
}

.badge-pending::after {
  content: '→';
  opacity: 0.6;
}

/* ─── Tables ───────────────────────────────────────────────── */
.table-container {
  width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  margin: 16px 0;
  border-radius: 12px;
  border: 1px solid var(--border);
}

table {
  width: 100%;
  border-collapse: collapse;
  min-width: 500px; /* Force scroll on small screens */
}

@media (min-width: 768px) {
  .table-container {
    border: none;
    margin: 0;
  }
  table {
    min-width: 100%;
  }
}

th, td {
  padding: 12px 16px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

th {
  color: var(--text-secondary);
  font-weight: 600;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

tbody tr {
  transition: background var(--transition-fast);
}

tbody tr:hover {
  background: rgba(255, 255, 255, 0.02);
}

/* ─── Concept Feed ─────────────────────────────────────────── */
.concept-feed {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin: 16px 0;
}

.concept-detail-panel {
  padding: 24px;
}

@media (min-width: 768px) {
  .concept-detail-panel {
    padding: 40px;
  }
}

.concept-header-row {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 24px;
}

@media (max-width: 480px) {
  .concept-header-row {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }
}

.section-divider {
  display: flex;
  align-items: center;
  gap: 12px;
  margin: 24px 0 16px;
  color: var(--text-secondary);
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.section-divider::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border);
}

.concept-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 18px 20px;
  display: flex;
  align-items: center;
  gap: 16px;
  transition: all var(--transition-normal);
  text-decoration: none;
  color: inherit;
}

.concept-card:hover {
  transform: translateX(6px);
  border-color: var(--accent);
  background: var(--panel-hover);
  box-shadow: var(--shadow-md);
}

.concept-card.completed {
  border-color: rgba(52, 211, 153, 0.3);
  opacity: 0.85;
}

.concept-card.completed:hover {
  border-color: var(--success);
  opacity: 1;
}

.concept-order {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 14px;
  font-weight: 700;
  font-size: 1rem;
  flex-shrink: 0;
  background: var(--accent-glow);
  color: var(--accent);
  border: 1px solid rgba(108, 159, 255, 0.2);
}

@media (min-width: 768px) {
  .concept-order {
    width: 56px;
    height: 56px;
    font-size: 1.1rem;
  }
}

.concept-card:not(.completed) .concept-order {
  /* Inherits base styles */
}

.concept-card.completed .concept-order {
  background: var(--success-glow);
  color: var(--success);
  border: 1px solid rgba(52, 211, 153, 0.2);
}

.concept-body {
  flex: 1;
  min-width: 0;
}

.concept-body .h2 {
  margin: 0 0 4px;
}

.concept-body p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--text-secondary);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.concept-status {
  flex-shrink: 0;
}

/* ─── Progress Bars ────────────────────────────────────────── */
.progress-container {
  background: rgba(255, 255, 255, 0.05);
  border-radius: 999px;
  height: 10px;
  margin: 12px 0;
  overflow: hidden;
}

.progress-bar {
  background: linear-gradient(90deg, var(--accent) 0%, var(--accent-strong) 100%);
  height: 100%;
  border-radius: 999px;
  transition: width 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.progress-bar.done {
  background: linear-gradient(90deg, var(--success) 0%, var(--success-strong) 100%);
}

/* ─── Gamification & Stats ─────────────────────────────────── */
.stats-overview-panel {
  background: linear-gradient(135deg, var(--panel) 0%, var(--bg-elevated) 100%);
}

.stats-overview-row {
  display: flex;
  margin-bottom: 20px;
  gap: 12px;
}

@media (max-width: 480px) {
  .stats-overview-row {
    flex-wrap: wrap;
  }
}

.stat-overview-item {
  text-align: center;
  flex: 1;
  min-width: 80px;
}

.stat-overview-value {
  font-size: 1.75rem;
  font-weight: 800;
  line-height: 1.2;
}

@media (min-width: 768px) {
  .stat-overview-value {
    font-size: 2.5rem;
  }
}

.stat-overview-value.level { color: var(--accent); }
.stat-overview-value.streak { color: var(--streak); }
.stat-overview-value.xp { color: var(--success); }

.next-level-target {
  float: right;
}

@media (max-width: 480px) {
  .next-level-target {
    float: none;
    display: block;
    margin-top: 4px;
  }
}

.streak-mini {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border-radius: 12px;
  background: var(--streak-glow);
  color: var(--streak);
  font-weight: 700;
  font-size: 1rem;
}

.xp-tag {
  color: var(--success);
  font-weight: 700;
  font-size: 0.9rem;
}

.level-badge {
  background: var(--accent);
  color: #ffffff;
  padding: 3px 10px;
  border-radius: 8px;
  font-weight: 700;
  font-size: 0.75rem;
  vertical-align: middle;
  margin-left: 6px;
}

/* ─── Quiz UI ──────────────────────────────────────────────── */
.quiz-container {
  max-width: 720px;
  margin: 0 auto;
}

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

.quiz-progress {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.quiz-progress-dots {
  display: flex;
  gap: 6px;
}

.quiz-progress-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--border);
  transition: all var(--transition-fast);
}

.quiz-progress-dot.answered {
  background: var(--accent);
}

.quiz-progress-dot.current {
  background: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.question-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 28px;
  margin: 20px 0;
  transition: border-color var(--transition-fast);
}

.question-card:focus-within {
  border-color: var(--accent);
}

.question-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 10px;
  background: var(--accent-glow);
  color: var(--accent);
  font-weight: 700;
  font-size: 0.9rem;
  margin-bottom: 16px;
}

.question-text {
  font-size: 1.15rem;
  font-weight: 500;
  line-height: 1.5;
  margin-bottom: 24px;
}

/* Modern Radio Buttons */
.answer-options {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.answer-option {
  position: relative;
}

.answer-option input {
  position: absolute;
  opacity: 0;
  width: 100%;
  height: 100%;
  cursor: pointer;
  z-index: 2;
}

.answer-option label {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 20px;
  border-radius: 14px;
  border: 2px solid var(--border);
  background: var(--bg-elevated);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-weight: 500;
  color: var(--text);
  margin: 0;
}

.answer-option label::before {
  content: '';
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 2px solid var(--border);
  background: var(--bg);
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.answer-option:hover label {
  border-color: var(--accent);
  background: rgba(108, 159, 255, 0.05);
}

.answer-option input:checked + label {
  border-color: var(--accent);
  background: var(--accent-glow);
}

.answer-option input:checked + label::before {
  border-color: var(--accent);
  background: var(--accent);
  box-shadow: inset 0 0 0 4px var(--bg);
}

.answer-option input:focus-visible + label {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* Quiz Results */
.result-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 20px;
  border-radius: 14px;
  font-size: 1.1rem;
  font-weight: 700;
}

.result-badge.correct {
  background: var(--success-glow);
  color: var(--success);
  border: 1px solid rgba(52, 211, 153, 0.3);
}

.result-badge.incorrect {
  background: var(--danger-glow);
  color: var(--danger);
  border: 1px solid rgba(248, 113, 113, 0.3);
}

.score-display {
  text-align: center;
  padding: 32px;
  background: linear-gradient(135deg, var(--panel) 0%, var(--bg-elevated) 100%);
  border-radius: 20px;
  margin: 24px 0;
}

.score-big {
  font-size: 4rem;
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1;
  margin-bottom: 8px;
  background: linear-gradient(135deg, var(--accent) 0%, var(--success) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.score-label {
  font-size: 1.1rem;
  color: var(--text-secondary);
  font-weight: 500;
}

/* ─── Flashcard UI ─────────────────────────────────────────── */
.flashcard-container {
  max-width: 640px;
  margin: 0 auto;
}

.flashcard-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
}

.cards-remaining {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  border-radius: 10px;
  background: var(--accent-glow);
  color: var(--accent);
  font-weight: 600;
  font-size: 0.9rem;
}

.flashcard {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: 40px 36px;
  min-height: 280px;
  display: flex;
  flex-direction: column;
  transition: all var(--transition-normal);
}

.flashcard:hover {
  border-color: var(--border-hover);
  box-shadow: var(--shadow-md);
}

.flashcard-label {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin-bottom: 16px;
}

.flashcard-content {
  font-size: 1.35rem;
  line-height: 1.6;
  font-weight: 500;
  flex: 1;
}

.flashcard-divider {
  height: 1px;
  background: var(--border);
  margin: 28px 0;
}

.flashcard-answer {
  animation: fadeSlideUp 0.3s ease;
}

@keyframes fadeSlideUp {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}

.rating-buttons {
  display: flex;
  gap: 12px;
  margin-top: 24px;
}

.rating-btn {
  flex: 1;
  padding: 16px 20px;
  border-radius: 14px;
  font-weight: 600;
  font-size: 1rem;
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.rating-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.rating-btn.again {
  background: var(--danger-glow);
  color: var(--danger);
  border: 1px solid rgba(248, 113, 113, 0.3);
}

.rating-btn.again:hover {
  background: var(--danger);
  color: white;
}

.rating-btn.good {
  background: var(--success-glow);
  color: var(--success);
  border: 1px solid rgba(52, 211, 153, 0.3);
}

.rating-btn.good:hover {
  background: var(--success);
  color: white;
}

.rating-btn.easy {
  background: var(--warning-glow);
  color: var(--warning);
  border: 1px solid rgba(251, 191, 36, 0.3);
}

.rating-btn.easy:hover {
  background: var(--warning);
  color: var(--bg);
}

.rating-subtitle {
  font-size: 0.75rem;
  opacity: 0.7;
  font-weight: 500;
}

/* Flashcard Celebration */
.celebration {
  text-align: center;
  padding: 48px 32px;
}

.celebration-icon {
  font-size: 4rem;
  margin-bottom: 16px;
  animation: bounce 0.6s ease;
}

@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-20px); }
}

.celebration h2 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.celebration p {
  color: var(--text-secondary);
  font-size: 1.1rem;
}

.stats-row {
  display: flex;
  justify-content: center;
  gap: 32px;
  margin: 24px 0;
}

.stat-item {
  text-align: center;
}

.stat-value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent);
}

.stat-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* ─── Writing UI ───────────────────────────────────────────── */
.writing-container {
  max-width: 800px;
  margin: 0 auto;
}

.prompt-card {
  background: linear-gradient(135deg, var(--panel) 0%, var(--bg-elevated) 100%);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 28px;
  margin-bottom: 24px;
}

.prompt-title {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.prompt-text {
  font-size: 1.05rem;
  line-height: 1.7;
  color: var(--text-secondary);
}

.existing-submission-notice {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 20px;
  border-radius: 14px;
  background: var(--accent-glow);
  border: 1px solid rgba(108, 159, 255, 0.2);
  margin-bottom: 20px;
}

.existing-submission-notice .icon {
  font-size: 1.5rem;
}

/* ─── Activity Cards ───────────────────────────────────────── */
.activity-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
  margin: 20px 0;
}

.activity-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 20px;
  text-align: center;
  transition: all var(--transition-fast);
}

.activity-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-2px);
}

.activity-icon {
  font-size: 2rem;
  margin-bottom: 12px;
}

.activity-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 4px;
}

.activity-value {
  font-size: 1.5rem;
  font-weight: 700;
}

.activity-value.success {
  color: var(--success);
}

.activity-value.accent {
  color: var(--accent);
}

/* ─── AI Results ───────────────────────────────────────────── */
.ai-result-row {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: 12px;
}

@media (max-width: 480px) {
  .ai-result-row {
    flex-direction: column;
    align-items: stretch;
    gap: 8px;
  }
}

.ai-progress-col {
  flex: 1;
}

.ai-score-col {
  min-width: 80px;
  text-align: right;
}

@media (max-width: 480px) {
  .ai-score-col {
    text-align: left;
  }
}

.ai-score-value {
  font-size: 1.3rem;
  font-weight: 700;
}

.ai-score-value.flagged { color: var(--warning); }
.ai-score-value.clean { color: var(--success); }

/* ─── Footer ───────────────────────────────────────────────── */
.footer {
  padding: 32px 0 48px;
  font-size: 0.85rem;
  color: var(--text-muted);
  text-align: center;
}

/* ─── Utility Classes ──────────────────────────────────────── */
.text-center { text-align: center; }
.mt-0 { margin-top: 0; }
.mt-4 { margin-top: 16px; }
.mt-6 { margin-top: 24px; }
.mb-0 { margin-bottom: 0; }
.mb-4 { margin-bottom: 16px; }
.mb-6 { margin-bottom: 24px; }
.gap-sm { gap: 8px; }
.gap-md { gap: 16px; }

/* ─── Mobile Responsiveness ────────────────────────────────── */
@media (max-width: 480px) {
  .quiz-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
  }

  .quiz-progress {
    width: 100%;
    justify-content: space-between;
  }
}

/* ─── Accessibility ─────────────────────────────────────────── */

/* Skip link - visible on focus for keyboard users */
.skip-link {
  position: absolute;
  top: -100px;
  left: 50%;
  transform: translateX(-50%);
  padding: 12px 24px;
  background: var(--accent);
  color: white;
  font-weight: 600;
  border-radius: 0 0 8px 8px;
  z-index: 10000;
  transition: top 0.2s ease;
  text-decoration: none;
}

.skip-link:focus {
  top: 0;
  outline: none;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Reset fieldset for semantic radio groups */
fieldset.answer-options,
fieldset.mc-options {
  border: none;
  padding: 0;
  margin: 0;
}

/* ─── Theme Toggle ──────────────────────────────────────────── */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.theme-toggle:hover {
  background: rgba(0, 0, 0, 0.05);
  color: var(--text);
  border-color: var(--border-hover);
}

[data-theme="dark"] .theme-toggle:hover {
  background: rgba(255, 255, 255, 0.05);
}

.theme-toggle svg {
  width: 18px;
  height: 18px;
}

/* Show sun in dark mode, moon in light mode */
.theme-toggle .icon-sun {
  display: none;
}

.theme-toggle .icon-moon {
  display: block;
}

[data-theme="dark"] .theme-toggle .icon-sun {
  display: block;
}

[data-theme="dark"] .theme-toggle .icon-moon {
  display: none;
}

/* ─── Reading Content (Improved Readability) ─────────────────── */
.reading-content {
  max-width: var(--content-width);
  margin-left: auto;
  margin-right: auto;
  line-height: 1.75;
  font-size: 1.05rem;
}

.reading-content p {
  margin-bottom: 1.25em;
}

/* Markdown-rendered content styles */
.markdown-content {
  max-width: var(--content-width);
  margin-left: auto;
  margin-right: auto;
  line-height: 1.75;
  font-size: 1.05rem;
}

.markdown-content h1,
.markdown-content h2,
.markdown-content h3,
.markdown-content h4 {
  margin-top: 1.5em;
  margin-bottom: 0.75em;
  font-weight: 600;
  line-height: 1.3;
}

.markdown-content h1 { font-size: 1.75rem; }
.markdown-content h2 { font-size: 1.4rem; }
.markdown-content h3 { font-size: 1.2rem; }
.markdown-content h4 { font-size: 1.1rem; }

.markdown-content p {
  margin-bottom: 1.25em;
}

.markdown-content ul,
.markdown-content ol {
  margin-bottom: 1.25em;
  padding-left: 1.5em;
}

.markdown-content li {
  margin-bottom: 0.5em;
}

.markdown-content strong {
  font-weight: 600;
  color: var(--text);
}

.markdown-content em {
  font-style: italic;
}

.markdown-content code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.9em;
  padding: 0.15em 0.4em;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 4px;
}

.markdown-content pre {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1em;
  overflow-x: auto;
  margin-bottom: 1.25em;
}

.markdown-content pre code {
  padding: 0;
  background: none;
  border: none;
}

.markdown-content blockquote {
  border-left: 3px solid var(--accent);
  padding-left: 1em;
  margin: 1.25em 0;
  color: var(--text-secondary);
  font-style: italic;
}

.markdown-content table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.25em;
}

.markdown-content th,
.markdown-content td {
  padding: 0.75em;
  text-align: left;
  border: 1px solid var(--border);
}

.markdown-content th {
  background: var(--bg-elevated);
  font-weight: 600;
}

.markdown-content hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 2em 0;
}

/* ─── Breadcrumbs ───────────────────────────────────────────── */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 16px;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.breadcrumb a {
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

.breadcrumb a:hover {
  color: var(--accent);
}

/* ─── Form Improvements ─────────────────────────────────────── */
.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  margin-bottom: 8px;
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
}

.form-error {
  color: var(--danger);
  font-size: 0.85rem;
  margin-top: 6px;
  margin-bottom: 0;
}

.help-text {
  margin-top: 6px;
  margin-bottom: 0;
}

/* ─── Filter Bar ────────────────────────────────────────────── */
.filter-bar {
  display: flex;
  align-items: center;
  gap: 16px;
  margin: 16px 0;
  padding: 12px 16px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
}

.filter-form {
  display: flex;
  align-items: center;
  gap: 16px;
}

.filter-checkbox {
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.filter-checkbox input[type="checkbox"] {
  width: 18px;
  height: 18px;
  cursor: pointer;
  accent-color: var(--accent);
}

/* ─── Badges ────────────────────────────────────────────────── */
.badge-warning {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 10px;
  border-radius: 6px;
  background: var(--warning-glow);
  color: var(--warning);
  font-size: 0.8rem;
  font-weight: 600;
}

.badge-ok {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 10px;
  border-radius: 6px;
  background: var(--success-glow);
  color: var(--success);
  font-size: 0.8rem;
  font-weight: 600;
}

/* ─── Teacher Submissions ───────────────────────────────────── */
.submission-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.flagged-row {
  background: var(--warning-glow);
}

.submission-meta {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 20px;
}

.submission-text {
  padding: 20px;
  background: var(--bg-elevated);
  border-radius: 12px;
  line-height: 1.8;
  margin-top: 16px;
}

.panel-warning {
  border-color: var(--warning);
  background: var(--warning-glow);
}

/* ─── Empty States ──────────────────────────────────────────── */
.empty-state {
  text-align: center;
  padding: 60px 20px;
}

.empty-icon {
  font-size: 4rem;
  margin-bottom: 16px;
  opacity: 0.6;
}

.empty-state h2 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 8px;
}

/* ─── Character Counter ─────────────────────────────────────── */
.char-counter {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 8px;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.char-counter.warning {
  color: var(--warning);
}

.char-counter.error {
  color: var(--danger);
}

/* ─── Loading States ────────────────────────────────────────── */
.btn.loading {
  position: relative;
  color: transparent;
  pointer-events: none;
}

.btn.loading::after {
  content: '';
  position: absolute;
  width: 18px;
  height: 18px;
  border: 2px solid transparent;
  border-top-color: currentColor;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  left: 50%;
  top: 50%;
  margin-left: -9px;
  margin-top: -9px;
}

.btn.loading::after {
  border-top-color: var(--bg);
}

.btn-lite.loading::after {
  border-top-color: var(--text);
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ─── Smooth Reveal Animation ───────────────────────────────── */
.reveal-animation {
  animation: revealSlide 0.3s ease-out;
}

@keyframes revealSlide {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ─── Progress Bar Warning State ────────────────────────────── */
.progress-bar.warning {
  background: linear-gradient(90deg, var(--warning) 0%, #f59e0b 100%);
}

/* ─── Keyboard Hints ────────────────────────────────────────── */
.kbd {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 20px;
  height: 20px;
  padding: 0 6px;
  margin-left: 6px;
  font-size: 0.7rem;
  font-weight: 600;
  font-family: 'JetBrains Mono', monospace;
  background: rgba(0, 0, 0, 0.2);
  border-radius: 4px;
  opacity: 0.7;
}

@media (max-width: 768px) {
  .kbd {
    display: none;
  }
}

/* ─── Warning Banner ────────────────────────────────────────── */
.warning-banner {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px 18px;
  margin-bottom: 20px;
  background: var(--warning-glow);
  border: 1px solid var(--warning);
  border-radius: 12px;
  color: var(--text);
}

.warning-banner-icon {
  flex-shrink: 0;
  font-size: 1.25rem;
  line-height: 1;
}

.warning-banner-content {
  flex: 1;
}

.warning-banner-title {
  font-weight: 600;
  margin-bottom: 4px;
}

.warning-banner-text {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin: 0;
}

.warning-banner a {
  color: var(--accent);
  font-weight: 500;
}

/* ─── Info Banner ───────────────────────────────────────────── */
.info-banner {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px 18px;
  margin-bottom: 20px;
  background: var(--accent-glow);
  border: 1px solid var(--accent);
  border-radius: 12px;
  color: var(--text);
}

.info-banner-icon {
  flex-shrink: 0;
  font-size: 1.25rem;
  line-height: 1;
}

/* ─── Section Detail Page ───────────────────────────────────── */
.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
  max-width: var(--content-width);
  margin-left: auto;
  margin-right: auto;
}

.section-header h1 {
  margin: 0;
  font-size: 1.75rem;
}

.due-date {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.due-date.overdue {
  color: var(--danger);
}

.mark-read-form {
  margin-top: 24px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
}

.read-badge {
  margin-top: 24px;
  padding: 12px;
  background: var(--accent-glow);
  border-radius: 8px;
  color: var(--accent);
  text-align: center;
}

/* ─── Mastery Check Cards ───────────────────────────────────── */
.mastery-checks {
  margin-top: 32px;
  max-width: var(--content-width);
  margin-left: auto;
  margin-right: auto;
}

.mastery-checks h2 {
  font-size: 1.25rem;
  margin-bottom: 16px;
}

.mastery-check-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
  margin-bottom: 20px;
}

.mastery-check-card.passed {
  border-color: var(--success);
  background: var(--success-glow);
}

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

.check-title {
  font-weight: 600;
  font-size: 1.1rem;
}

.status-badge {
  padding: 4px 10px;
  border-radius: 12px;
  font-size: 0.8rem;
  font-weight: 500;
}

.status-badge.success {
  background: var(--success);
  color: white;
}

.status-badge.warning {
  background: var(--warning);
  color: #333;
}

.check-prompt {
  margin-bottom: 12px;
  color: var(--text);
}

.word-limit {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 16px;
}

/* Previous response - subtle, collapsed feel */
.previous-response {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 16px;
  margin-bottom: 12px;
  opacity: 0.85;
}

.previous-response h4 {
  margin: 0 0 6px 0;
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.prev-text {
  font-size: 0.9rem;
  white-space: pre-wrap;
  line-height: 1.5;
  color: var(--text-secondary);
}

/* Grader feedback - prominent card that stands out */
.grader-feedback {
  background: var(--warning-glow);
  border: 1px solid var(--warning);
  border-radius: 8px;
  padding: 16px;
  margin-bottom: 16px;
}

.grader-feedback h4 {
  margin: 0 0 8px 0;
  font-size: 0.8rem;
  color: var(--warning);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.grader-feedback .feedback-text {
  font-size: 0.95rem;
  line-height: 1.6;
  color: var(--text);
}

.grader-feedback.ai-flagged {
  background: var(--danger-glow);
  border-color: var(--danger);
}

.grader-feedback.ai-flagged h4 {
  color: var(--danger);
}

/* Legacy class for backwards compatibility */
.previous-attempt {
  background: var(--warning-glow);
  border: 1px solid var(--warning);
  border-radius: 8px;
  padding: 16px;
  margin-bottom: 16px;
}

.previous-attempt h4 {
  margin: 0 0 8px 0;
  font-size: 0.9rem;
}

.feedback {
  font-size: 0.9rem;
  padding-top: 12px;
  border-top: 1px solid var(--border);
}

.feedback.ai-flagged {
  color: var(--warning);
}

.check-locked,
.cooldown-notice {
  padding: 16px;
  background: var(--bg);
  border-radius: 8px;
  text-align: center;
}

.cooldown-notice {
  background: var(--warning-glow);
}

.check-form textarea {
  width: 100%;
  padding: 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg-elevated);
  color: var(--text);
  font-family: inherit;
  font-size: 1rem;
  resize: vertical;
  min-height: 150px;
}

.form-actions {
  margin-top: 12px;
  display: flex;
  justify-content: flex-end;
}

/* ─── Submit Button Loading State ────────────────────────────── */
.submit-btn {
  position: relative;
  min-width: 140px;
  overflow: hidden;
}

.submit-btn .btn-spinner,
.submit-btn .btn-loading-text {
  display: none;
}

.submit-btn.is-loading {
  pointer-events: none;
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-strong) 100%);
}

.submit-btn.is-loading .btn-text {
  display: none;
}

.submit-btn.is-loading .btn-spinner,
.submit-btn.is-loading .btn-loading-text {
  display: inline-flex;
  align-items: center;
}

.submit-btn .btn-spinner {
  width: 18px;
  height: 18px;
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-top-color: white;
  border-radius: 50%;
  animation: spinnerRotate 0.8s linear infinite;
  margin-right: 8px;
}

@keyframes spinnerRotate {
  to { transform: rotate(360deg); }
}

.submit-btn .btn-loading-text {
  font-size: 0.9rem;
  animation: loadingPulse 1.5s ease-in-out infinite;
}

@keyframes loadingPulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.7; }
}

/* Shimmer effect on button while loading */
.submit-btn.is-loading::after {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255, 255, 255, 0.2),
    transparent
  );
  animation: loadingShimmer 1.5s ease-in-out infinite;
}

@keyframes loadingShimmer {
  0% { left: -100%; }
  100% { left: 100%; }
}

.passed-message {
  padding: 12px;
  background: var(--success-glow);
  border-radius: 8px;
  color: var(--success);
  text-align: center;
}

.passed-message .your-response {
  margin-top: 12px;
  text-align: left;
  color: var(--text-secondary);
}

.passed-message .your-response summary {
  cursor: pointer;
  font-weight: 500;
  color: var(--success);
}

.passed-message .your-response summary:hover {
  text-decoration: underline;
}

.passed-message .response-text {
  margin-top: 12px;
  padding: 12px;
  background: var(--panel);
  border-radius: 6px;
  color: var(--text);
  line-height: 1.6;
  white-space: pre-wrap;
}

.passed-message .response-feedback {
  margin-top: 8px;
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* ─── Flashcard Prompt ───────────────────────────────────────── */
.flashcard-prompt {
  margin-top: 24px;
  max-width: var(--content-width);
  margin-left: auto;
  margin-right: auto;
  background: var(--accent-glow);
  border-color: var(--accent);
}

.flashcard-prompt-content {
  display: flex;
  align-items: center;
  gap: 16px;
}

.flashcard-prompt-icon {
  font-size: 2rem;
  flex-shrink: 0;
}

.flashcard-prompt-text {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.flashcard-prompt-text strong {
  color: var(--accent);
}

@media (max-width: 480px) {
  .flashcard-prompt-content {
    flex-direction: column;
    text-align: center;
  }

  .flashcard-prompt-text {
    align-items: center;
  }
}

.nav-buttons {
  margin-top: 32px;
  max-width: var(--content-width);
  margin-left: auto;
  margin-right: auto;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

@media (max-width: 480px) {
  .nav-buttons {
    flex-direction: column;
  }

  .nav-buttons .btn {
    width: 100%;
    text-align: center;
  }
}

/* ═══════════════════════════════════════════════════════════
   Dopamine Enhancers - Satisfying Micro-interactions
   ═══════════════════════════════════════════════════════════ */

/* ─── Smooth Page Entrance ──────────────────────────────────── */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes scaleIn {
  from {
    opacity: 0;
    transform: scale(0.95);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

/* Staggered entrance for lists */
.panel,
.activity-card,
.section-item,
.mastery-check-card,
.concept-card {
  animation: fadeInUp 0.4s ease backwards;
}

.panel:nth-child(1) { animation-delay: 0.05s; }
.panel:nth-child(2) { animation-delay: 0.1s; }
.panel:nth-child(3) { animation-delay: 0.15s; }
.panel:nth-child(4) { animation-delay: 0.2s; }

.section-item:nth-child(1) { animation-delay: 0.05s; }
.section-item:nth-child(2) { animation-delay: 0.1s; }
.section-item:nth-child(3) { animation-delay: 0.15s; }
.section-item:nth-child(4) { animation-delay: 0.2s; }
.section-item:nth-child(5) { animation-delay: 0.25s; }

/* ─── Interactive Element Polish ────────────────────────────── */

/* Buttons with satisfying press */
.btn {
  transition: all var(--transition-fast);
  transform: translateY(0);
}

.btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn:active {
  transform: translateY(1px);
  box-shadow: none;
}

/* Cards lift on hover */
.activity-card,
.section-item,
.concept-card,
.mc-option {
  transition: all var(--transition-fast);
}

.activity-card:hover,
.concept-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.section-item:not(.locked):hover {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent-glow);
}

/* ─── Success Celebration Animation ─────────────────────────── */
@keyframes successPop {
  0% { transform: scale(1); }
  50% { transform: scale(1.15); }
  100% { transform: scale(1); }
}

@keyframes checkmark {
  0% {
    stroke-dashoffset: 50;
  }
  100% {
    stroke-dashoffset: 0;
  }
}

@keyframes successGlow {
  0% { box-shadow: 0 0 0 0 var(--success-glow); }
  50% { box-shadow: 0 0 20px 10px var(--success-glow); }
  100% { box-shadow: 0 0 0 0 transparent; }
}

.success-pop {
  animation: successPop 0.3s ease;
}

.success-glow {
  animation: successGlow 0.6s ease;
}

/* Flashcard correct answer celebration */
.feedback-result.correct {
  animation: scaleIn 0.3s ease, successGlow 0.6s ease 0.1s;
}

.feedback-result.correct .feedback-icon {
  animation: successPop 0.4s ease 0.15s;
}

/* ─── Progress Bar Animations ───────────────────────────────── */
.progress-bar {
  transition: width 0.6s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  overflow: hidden;
}

/* Animated progress with shine effect */
@keyframes progressShine {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}

.progress-bar::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255, 255, 255, 0.3),
    transparent
  );
  animation: progressShine 2s ease-in-out infinite;
}

.progress-bar-container {
  position: relative;
  overflow: hidden;
}

/* ─── Status Badge Animations ───────────────────────────────── */
.badge.done,
.badge-done,
.status-badge.success {
  position: relative;
  overflow: hidden;
}

/* ─── Streak Fire Animation ─────────────────────────────────── */
@keyframes fireFlicker {
  0%, 100% { transform: scale(1) rotate(0deg); }
  25% { transform: scale(1.05) rotate(-2deg); }
  75% { transform: scale(0.98) rotate(2deg); }
}

.streak-mini {
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.streak-mini:hover {
  animation: fireFlicker 0.5s ease infinite;
}

/* ─── Level Badge Shine ─────────────────────────────────────── */
@keyframes levelShine {
  0% { background-position: -200% center; }
  100% { background-position: 200% center; }
}

/* ─── Checkbox/Radio Selection Animation ────────────────────── */
.mc-option {
  position: relative;
  overflow: hidden;
}

.mc-option::after {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--success-glow);
  opacity: 0;
  transform: scale(0);
  transition: all 0.3s ease;
  border-radius: inherit;
  pointer-events: none;
}

.mc-option:has(input:checked)::after {
  opacity: 1;
  transform: scale(1);
}

.mc-option input:checked + .mc-option-text {
  font-weight: 500;
}

/* ─── Reading Progress Indicator ────────────────────────────── */
.reading-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), var(--success));
  z-index: 1001;
  transition: width 0.1s linear;
}

/* ─── Smooth Number Counter ─────────────────────────────────── */
.stat-overview-value {
  font-variant-numeric: tabular-nums;
  transition: all 0.3s ease;
}

.stat-overview-value.level {
  background: linear-gradient(135deg, var(--accent), var(--accent-strong));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  font-weight: 700;
}

.stat-overview-value.streak {
  color: var(--streak);
}

.stat-overview-value.xp {
  color: var(--success);
}

/* ─── Flash Message Animations ──────────────────────────────── */
.flash {
  animation: slideInDown 0.4s ease;
}

@keyframes slideInDown {
  from {
    opacity: 0;
    transform: translateY(-20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Success flash gets extra celebration */
.flash.success {
  border-left: 4px solid var(--success);
}

/* ─── Typing/Text Area Focus ────────────────────────────────── */
textarea:focus,
input[type="text"]:focus,
input[type="email"]:focus,
input[type="password"]:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
  transition: all var(--transition-fast);
}

/* ─── Link Underline Animation ──────────────────────────────── */
.markdown-content a {
  color: var(--accent);
  text-decoration: none;
  background-image: linear-gradient(var(--accent), var(--accent));
  background-size: 0% 2px;
  background-position: 0 100%;
  background-repeat: no-repeat;
  transition: background-size 0.3s ease;
}

.markdown-content a:hover {
  background-size: 100% 2px;
}

/* ─── Skeleton Loading (for future use) ─────────────────────── */
@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

.skeleton {
  background: linear-gradient(
    90deg,
    var(--panel) 25%,
    var(--panel-hover) 50%,
    var(--panel) 75%
  );
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
  border-radius: 4px;
}

/* ─── Completed Section Checkmark ───────────────────────────── */
.status-icon.done {
  position: relative;
}

.status-icon.done::after {
  content: '';
  position: absolute;
  inset: -4px;
  border-radius: 50%;
  border: 2px solid var(--success);
  opacity: 0;
  animation: ringPulse 2s ease infinite;
}

@keyframes ringPulse {
  0%, 100% {
    transform: scale(1);
    opacity: 0;
  }
  50% {
    transform: scale(1.3);
    opacity: 0.3;
  }
}

/* ─── Smooth Scroll Behavior ────────────────────────────────── */
html {
  scroll-behavior: smooth;
}

/* ─── Focus Visible for Accessibility ───────────────────────── */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* ─── Word Count Live Feedback ──────────────────────────────── */
.word-count-display {
  font-size: 0.85rem;
  color: var(--text-muted);
  text-align: right;
  margin-top: 8px;
  font-variant-numeric: tabular-nums;
  transition: color 0.2s ease;
}

.word-count-display.in-range {
  color: var(--success);
}

.word-count-display.over-limit {
  color: var(--warning);
}

/* Form error container (accessible error messages) */
.form-error-container {
  display: none;
  padding: 12px 16px;
  margin-top: 8px;
  background: var(--danger-glow);
  border: 1px solid var(--danger);
  border-radius: 8px;
  color: var(--danger);
  font-size: 0.9rem;
  font-weight: 500;
}

/* ═══════════════════════════════════════════════════════════
   XP Toast Animation System - Tangible Reward Feedback
   ═══════════════════════════════════════════════════════════ */

/* XP Toast that floats up and "collects" into the topbar */
.xp-toast {
  position: fixed;
  z-index: 10000;
  pointer-events: none;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--success);
  text-shadow: 0 2px 8px rgba(16, 185, 129, 0.4);
  animation: xpFloat 1.5s cubic-bezier(0.4, 0, 0.2, 1) forwards;
  display: flex;
  align-items: center;
  gap: 4px;
}

.xp-toast::before {
  content: '+';
}

.xp-toast::after {
  content: ' XP';
  font-size: 0.9em;
  opacity: 0.9;
}

@keyframes xpFloat {
  0% {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
  20% {
    transform: translateY(-20px) scale(1.2);
  }
  100% {
    opacity: 0;
    transform: translateY(-80px) scale(0.8);
  }
}

/* Level badge pulse when XP is earned */
.level-badge.xp-pulse {
  animation: levelPulse 0.6s ease;
}

@keyframes levelPulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.15); box-shadow: 0 0 12px var(--accent); }
}

/* ─── Session XP Counter ────────────────────────────────────── */
.session-xp {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border-radius: 12px;
  background: var(--success-glow);
  color: var(--success);
  font-weight: 700;
  font-size: 0.85rem;
  transition: all var(--transition-fast);
}

.session-xp:hover {
  background: var(--success);
  color: white;
}

.session-xp-value {
  font-variant-numeric: tabular-nums;
}

/* Pop animation when session XP increases */
.session-xp.xp-bump {
  animation: sessionBump 0.4s ease;
}

@keyframes sessionBump {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.1); }
}

/* ─── Level Progress Ring ───────────────────────────────────── */
.level-progress-ring {
  position: relative;
  display: flex;
  align-items: center;
  gap: 6px;
}

.level-ring-svg {
  width: 32px;
  height: 32px;
  transform: rotate(-90deg);
}

.level-ring-bg {
  fill: none;
  stroke: var(--border);
  stroke-width: 3;
}

.level-ring-progress {
  fill: none;
  stroke: var(--accent);
  stroke-width: 3;
  stroke-linecap: round;
  transition: stroke-dashoffset 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.level-ring-text {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%) translateX(-16px);
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--accent);
  width: 32px;
  text-align: center;
}

/* Glow effect when progress increases */
.level-progress-ring.progress-bump .level-ring-progress {
  filter: drop-shadow(0 0 4px var(--accent));
}

/* ─── Combo/Streak Multiplier ───────────────────────────────── */
.combo-display {
  position: fixed;
  top: 80px;
  right: 20px;
  z-index: 9999;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 12px 20px;
  background: linear-gradient(135deg, var(--streak) 0%, #ef4444 100%);
  color: white;
  border-radius: 16px;
  box-shadow: 0 4px 20px rgba(249, 115, 22, 0.4);
  opacity: 0;
  transform: translateX(100px);
  transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  pointer-events: none;
}

.combo-display.visible {
  opacity: 1;
  transform: translateX(0);
}

.combo-display.combo-bump {
  animation: comboBump 0.3s ease;
}

@keyframes comboBump {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.15); }
}

.combo-count {
  font-size: 2rem;
  font-weight: 800;
  line-height: 1;
}

.combo-label {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  opacity: 0.9;
}

.combo-bonus {
  font-size: 0.8rem;
  font-weight: 700;
  margin-top: 4px;
  padding: 2px 8px;
  background: rgba(255, 255, 255, 0.2);
  border-radius: 8px;
}

/* Combo fire particles */
.combo-display::before {
  content: '🔥';
  position: absolute;
  top: -8px;
  right: -8px;
  font-size: 1.5rem;
  animation: fireFloat 1s ease-in-out infinite;
}

@keyframes fireFloat {
  0%, 100% { transform: translateY(0) rotate(-5deg); }
  50% { transform: translateY(-4px) rotate(5deg); }
}

/* Hide combo on mobile if it's too intrusive */
@media (max-width: 480px) {
  .combo-display {
    top: auto;
    bottom: 80px;
    right: 10px;
    padding: 8px 14px;
  }

  .combo-count {
    font-size: 1.5rem;
  }
}

/* ─── Sound Toggle Button ───────────────────────────────────── */
.sound-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.sound-toggle:hover {
  background: rgba(0, 0, 0, 0.05);
  color: var(--text);
  border-color: var(--border-hover);
}

[data-theme="dark"] .sound-toggle:hover {
  background: rgba(255, 255, 255, 0.05);
}

.sound-toggle svg {
  width: 18px;
  height: 18px;
}

.sound-toggle .icon-sound-off {
  display: none;
}

.sound-toggle.muted .icon-sound-on {
  display: none;
}

.sound-toggle.muted .icon-sound-off {
  display: block;
}

.sound-toggle.muted {
  opacity: 0.5;
}

/* Bug Report System */
.report-issue-section {
  margin-top: 16px;
  padding: 12px;
  border-radius: 8px;
  background: var(--surface);
  border: 1px solid var(--border);
}

.report-help-text {
  margin: 0 0 8px 0;
  font-size: 0.9rem;
  color: var(--muted);
}

.report-status-pending,
.report-status-resolved {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border-radius: 6px;
  font-size: 0.9rem;
}

.report-status-pending {
  background: rgba(245, 158, 11, 0.1);
  color: #d97706;
  border: 1px solid rgba(245, 158, 11, 0.3);
}

.report-status-resolved {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 12px;
  border-radius: 6px;
  font-size: 0.9rem;
  background: rgba(34, 197, 94, 0.1);
  color: #059669;
  border: 1px solid rgba(34, 197, 94, 0.3);
}

.report-status-resolved .teacher-note {
  margin: 4px 0 0 0;
  padding: 8px;
  background: rgba(255, 255, 255, 0.5);
  border-radius: 4px;
  font-size: 0.85rem;
  color: var(--fg);
}

.report-status-rejected {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 12px;
  border-radius: 6px;
  font-size: 0.9rem;
  background: rgba(107, 114, 128, 0.1);
  color: var(--fg);
  border: 1px solid rgba(107, 114, 128, 0.3);
}

.report-status-rejected .teacher-note {
  margin: 8px 0 0 0;
  padding: 8px;
  background: var(--bg);
  border-radius: 4px;
  font-size: 0.85rem;
}

.report-status-pending .icon,
.report-status-resolved .icon,
.report-status-rejected .icon {
  font-size: 1.2rem;
}

/* Reduce motion for users who prefer it */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}