:root {
  --bg: #0a0a1a;
  --surface: #12122a;
  --surface2: #1a1a3a;
  --border: #2a2a5a;
  --text: #e0e0ff;
  --text-dim: #9999bb;
  --accent: #00ff88;
  --accent2: #00bbff;
  --accent3: #ff66cc;
  --gold: #ffcc00;
  --danger: #ff4444;
  --warning: #ff8800;
  --xp-color: #00ff88;
  --hp-color: #ff4466;
  --mana-color: #4488ff;
  --radius-sm: 4px;
  --radius: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.2);
  --shadow: 0 4px 16px rgba(0,0,0,0.3);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.4);
  --glow-accent: 0 0 20px rgba(0,255,136,0.15);
  --glow-gold: 0 0 20px rgba(255,204,0,0.15);
  --transition: 0.2s ease;
  --transition-slow: 0.4s cubic-bezier(0.4,0,0.2,1);
}

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

:focus-visible {
  outline: 2px solid var(--accent2);
  outline-offset: 2px;
}
:focus:not(:focus-visible) { outline: none; }

body {
  font-family: 'Inter', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  background-image:
    radial-gradient(ellipse at 20% 50%, rgba(0,255,136,0.04) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 20%, rgba(0,187,255,0.03) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 80%, rgba(255,102,204,0.02) 0%, transparent 50%);
  background-attachment: fixed;
}

.pixel-font { font-family: 'Press Start 2P', monospace; }

#app {
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.screen {
  display: none;
  max-width: 800px;
  margin: 0 auto;
  padding: 16px;
  animation: screenIn 0.25s ease-out;
  overflow-x: hidden;
}
.screen.active { display: block; }

@keyframes screenIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes slideUp {
  from { opacity: 0; transform: translateY(40px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes pulse { 0%,100% { transform: scale(1); } 50% { transform: scale(1.05); } }
@keyframes glow {
  0%,100% { box-shadow: 0 0 5px var(--accent); }
  50% { box-shadow: 0 0 20px var(--accent), 0 0 40px rgba(0,255,136,0.3); }
}
@keyframes float { 0%,100% { transform: translateY(0); } 50% { transform: translateY(-10px); } }
@keyframes spin { to { transform: rotate(360deg); } }
@keyframes confetti-fall {
  0% { transform: translate(0,0) rotate(0deg); opacity: 1; }
  100% { transform: translate(var(--dx), var(--dy)) rotate(var(--r)); opacity: 0; }
}
@keyframes pulse-gold {
  0%,100% { box-shadow: 0 0 5px rgba(255,204,0,0.2); }
  50% { box-shadow: 0 0 25px rgba(255,204,0,0.6); }
}
@keyframes lp-ambient {
  0% { transform: translate(0,0); }
  100% { transform: translate(-5%,-5%); }
}
@keyframes debugPulse { 0%,100% { opacity: 1; } 50% { opacity: 0.4; } }
@keyframes slideInRight {
  from { transform: translateX(20px); opacity: 0; }
}
@keyframes slideOutLeft {
  to { transform: translateX(-20px); opacity: 0; }
}
@keyframes fadeOut { to { opacity: 0; } }
@keyframes loadingSlide {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* ===== BUTTONS ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border: 2px solid var(--accent);
  background: rgba(0,255,136,0.1);
  color: var(--accent);
  font-family: 'Press Start 2P', monospace;
  font-size: 11px;
  cursor: pointer;
  text-transform: uppercase;
  letter-spacing: 1px;
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
  font-weight: 600;
}
.btn:hover {
  background: var(--accent);
  color: var(--bg);
  box-shadow: 0 0 20px rgba(0,255,136,0.4);
  transform: translateY(-2px);
}
.btn:active { transform: translateY(0); }
.btn-primary {
  border-color: var(--accent2);
  background: rgba(0,187,255,0.1);
  color: var(--accent2);
}
.btn-primary:hover {
  background: var(--accent2);
  color: var(--bg);
  box-shadow: 0 0 20px rgba(0,187,255,0.4);
}
.btn-gold {
  border-color: var(--gold);
  background: rgba(255,204,0,0.1);
  color: var(--gold);
}
.btn-gold:hover {
  background: var(--gold);
  color: var(--bg);
  box-shadow: 0 0 20px rgba(255,204,0,0.4);
}
.btn-gold-pulse { animation: pulse-gold 2s infinite; }
.btn-danger {
  border-color: var(--danger);
  background: rgba(255,68,68,0.1);
  color: var(--danger);
}
.btn-sm { padding: 8px 16px; font-size: 11px; }
.btn-lg { padding: 16px 36px; font-size: 13px; }
.btn-block { width: 100%; min-width: 0; max-width: 100%; justify-content: center; overflow: hidden; text-overflow: ellipsis; white-space: normal; line-height: 1.6; overflow-wrap: break-word; }

/* ===== CARDS ===== */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: all var(--transition);
}
.card:hover {
  border-color: var(--accent);
  box-shadow: 0 0 15px rgba(0,255,136,0.1);
}
.card-glow { animation: glow 2s infinite; }

/* ===== STATS BARS ===== */
.stat-bar {
  height: 8px;
  background: var(--surface2);
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: 1px solid var(--border);
}
.stat-bar-fill {
  height: 100%;
  border-radius: 3px;
  transition: width 0.8s ease;
  position: relative;
}
.stat-bar-fill::after {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 50%;
  background: rgba(255,255,255,0.15);
  border-radius: 3px 3px 0 0;
}
.xp-bar .stat-bar-fill { background: linear-gradient(90deg, var(--accent), #00dd77); }
.hp-bar .stat-bar-fill { background: linear-gradient(90deg, var(--danger), #ff6688); }
.mp-bar .stat-bar-fill { background: linear-gradient(90deg, var(--mana-color), #66aaff); }
.progress-bar .stat-bar-fill { background: linear-gradient(90deg, var(--accent2), #66ccff); }

/* ===== HEADER / HUD ===== */
.hud {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 24px;
}
.hud-left { display: flex; align-items: center; gap: 16px; }
.hud-right { display: flex; align-items: center; gap: 12px; }
.hud-avatar {
  width: 48px; height: 48px;
  border: 2px solid var(--accent);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  background: var(--surface2);
}
.hud-name { font-weight: 700; font-size: 16px; }
.hud-level {
  background: var(--accent);
  color: var(--bg);
  padding: 2px 10px;
  border-radius: var(--radius-sm);
  font-size: 11px;
  font-weight: 700;
}
.hud-xp { font-size: 13px; color: var(--xp-color); }
.hud-streak { font-size: 13px; color: var(--gold); }
.hud-badge { font-size: 13px; color: var(--text-dim); }

/* ===== NAV ===== */
.nav-bar {
  display: flex;
  gap: 8px;
  margin-bottom: 24px;
  padding: 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  flex-wrap: wrap;
}
.nav-item {
  padding: 8px 16px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 12px;
  font-weight: 600;
  transition: all var(--transition);
  background: none;
  color: var(--text-dim);
  font-family: inherit;
}
.nav-item:hover { color: var(--text); background: var(--surface2); }
.nav-item.active {
  color: var(--accent);
  border-color: var(--accent);
  background: rgba(0,255,136,0.1);
}

/* ===== USER SWITCHER ===== */
.user-switcher { position: relative; display: inline-block; }
.switcher-btn { cursor: pointer; }
.switcher-dropdown {
  display: none;
  position: absolute;
  top: 100%;
  right: 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  min-width: 200px;
  z-index: 1000;
  box-shadow: var(--shadow-lg);
  margin-top: 4px;
}
.switcher-dropdown.visible { display: block; }
.switcher-item {
  padding: 10px 14px;
  cursor: pointer;
  font-size: 13px;
  border-bottom: 1px solid var(--border);
  transition: background 0.2s;
}
.switcher-item:last-child { border-bottom: none; }
.switcher-item:hover { background: var(--surface2); }
.switcher-item.current { color: var(--accent); cursor: default; }
.switcher-item.disabled { color: var(--text-dim); cursor: default; text-align: center; }
.switcher-item.more-btn { color: var(--accent2); text-align: center; font-weight: 600; }

/* ===== INTRO SCREEN ===== */
#screen-intro {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 80vh;
  text-align: center;
}
.intro-title {
  font-family: 'Press Start 2P', monospace;
  font-size: 36px;
  color: var(--accent);
  text-shadow: 0 0 30px rgba(0,255,136,0.5), 0 0 60px rgba(0,255,136,0.2);
  margin-bottom: 16px;
  line-height: 1.4;
}
.intro-sub {
  font-size: 18px;
  color: var(--text-dim);
  margin-bottom: 40px;
  max-width: 600px;
  line-height: 1.6;
}
.intro-pixel {
  font-family: 'Press Start 2P', monospace;
  font-size: 60px;
  margin-bottom: 30px;
  animation: float 3s ease-in-out infinite;
}
.intro-features {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  max-width: 800px;
  margin: 40px 0;
}
.intro-feature {
  padding: 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.intro-feature-icon { font-size: 32px; margin-bottom: 12px; }
.intro-feature-title { font-weight: 600; margin-bottom: 8px; font-size: 14px; }
.intro-feature-desc { font-size: 12px; color: var(--text-dim); line-height: 1.5; }

/* ===== HUB SCREEN ===== */
#screen-hub .hub-grid {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 20px;
  min-width: 0;
}
#screen-hub .hub-grid > * {
  min-width: 0;
  overflow: hidden;
  overflow-wrap: break-word;
}
.hub-stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  margin-bottom: 20px;
}
.hub-stat {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  text-align: center;
}
.hub-stat-value { font-size: 28px; font-weight: 800; }
.hub-stat-label { font-size: 11px; color: var(--text-dim); margin-top: 4px; }
.hub-stat.xp .hub-stat-value { color: var(--xp-color); }
.hub-stat.level .hub-stat-value { color: var(--accent2); }
.hub-stat.streak .hub-stat-value { color: var(--gold); }
.hub-stat.lessons .hub-stat-value { color: var(--accent3); }

/* ===== IMPROVER PANEL ===== */
.improver-panel {
  background: var(--surface);
  border: 2px solid var(--gold);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 20px;
}
.improver-title {
  font-family: 'Press Start 2P', monospace;
  font-size: 14px;
  color: var(--gold);
  margin-bottom: 16px;
}
.improver-bar-container { margin-bottom: 12px; }
.improver-label {
  display: flex;
  justify-content: space-between;
  font-size: 12px;
  margin-bottom: 4px;
}
.improver-value { font-weight: 700; }

/* ===== WEAK TOPICS ===== */
.weak-topics {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.weak-topic-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
}
.weak-topic-name { font-weight: 600; font-size: 13px; }
.weak-topic-score { font-size: 12px; }
.weak-topic-score.low { color: var(--danger); }
.weak-topic-score.medium { color: var(--warning); }
.weak-topic-score.high { color: var(--accent); }

/* ===== SIDEBAR ===== */
.sidebar {
  display: flex;
  flex-direction: column;
  gap: 12px;
  min-width: 0;
}
.sidebar-card {
  padding: 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  min-width: 0;
}
.sidebar-card-title {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 12px;
}

/* ===== LESSONS BROWSE ===== */
.lp-header {
  text-align: center;
  padding: 32px 24px;
  margin-bottom: 32px;
  background: linear-gradient(135deg, rgba(0,255,136,0.05), rgba(0,187,255,0.05));
  border: 1px solid rgba(0,255,136,0.15);
  border-radius: var(--radius-xl);
  position: relative;
  overflow: hidden;
}
.lp-header::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background:
    radial-gradient(circle at 30% 50%, rgba(0,255,136,0.03) 0%, transparent 50%),
    radial-gradient(circle at 70% 50%, rgba(0,187,255,0.03) 0%, transparent 50%);
  animation: lp-ambient 8s ease-in-out infinite alternate;
}
.lp-header h2 {
  position: relative;
  z-index: 1;
  font-family: 'Press Start 2P', monospace;
  font-size: 22px;
  color: var(--accent);
  margin-bottom: 8px;
}
.lp-header p {
  position: relative;
  z-index: 1;
  color: var(--text-dim);
  font-size: 14px;
}
.lp-stats-row {
  display: flex;
  gap: 12px;
  justify-content: center;
  margin-top: 16px;
  position: relative;
  z-index: 1;
}
.lp-stat {
  padding: 8px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 12px;
  color: var(--text-dim);
  display: flex;
  align-items: center;
  gap: 6px;
}
.lp-stat strong { color: var(--accent); font-size: 14px; }
.lp-controls {
  display: flex;
  gap: 12px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}
.lp-search {
  flex: 1;
  min-width: 200px;
  padding: 12px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-family: inherit;
  font-size: 14px;
  transition: all var(--transition);
}
.lp-search:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-color: var(--accent);
  box-shadow: 0 0 20px rgba(0,255,136,0.15);
}
.lp-search::placeholder { color: var(--text-dim); }
.lp-filter {
  padding: 10px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text-dim);
  font-family: inherit;
  font-size: 13px;
  cursor: pointer;
  transition: all var(--transition);
}
.lp-filter:hover, .lp-filter.active {
  border-color: var(--accent);
  color: var(--accent);
}
.lp-filter.active { background: rgba(0,255,136,0.1); }
.lp-empty {
  text-align: center;
  padding: 64px 24px;
  color: var(--text-dim);
}
.lp-empty .icon { font-size: 48px; margin-bottom: 16px; opacity: 0.5; }
.lp-empty h3 { color: var(--text); margin-bottom: 8px; }

/* ===== TOPIC CARDS ===== */
.topic-card {
  margin-bottom: 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: all var(--transition-slow);
}
.topic-card:hover {
  border-color: rgba(0,255,136,0.3);
  box-shadow: 0 8px 32px rgba(0,0,0,0.3);
  transform: translateY(-2px);
}
.topic-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 24px;
  cursor: pointer;
  background: linear-gradient(135deg, rgba(0,255,136,0.02), transparent);
  border-bottom: 1px solid var(--border);
  transition: background var(--transition);
}
.topic-card-header:hover {
  background: linear-gradient(135deg, rgba(0,255,136,0.05), transparent);
}
.topic-card:not(.open) .topic-count::after {
  content: ' ↕ click';
  font-size: 10px;
  opacity: 0.5;
  transition: opacity var(--transition);
}
.topic-card:not(.open) .topic-card-header:hover .topic-count::after { opacity: 1; }
.topic-card-header-left {
  display: flex;
  align-items: center;
  gap: 16px;
}
.topic-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  background: var(--surface2);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
}
.topic-title {
  font-size: 16px;
  font-weight: 700;
  text-transform: capitalize;
  color: var(--text);
}
.topic-count {
  font-size: 12px;
  color: var(--text-dim);
  margin-top: 2px;
}
.topic-progress-ring {
  position: relative;
  width: 56px;
  height: 56px;
}
.topic-progress-ring svg { transform: rotate(-90deg); }
.topic-progress-ring .bg {
  fill: none;
  stroke: var(--border);
  stroke-width: 4;
}
.topic-progress-ring .fg {
  fill: none;
  stroke: var(--accent);
  stroke-width: 4;
  stroke-linecap: round;
  transition: stroke-dashoffset 1s var(--transition-slow);
}
.topic-progress-ring .pct {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  font-weight: 700;
  color: var(--accent);
}
.topic-card-body {
  padding: 0 24px;
  max-height: 0;
  overflow: hidden;
  transition: all var(--transition-slow);
}
.topic-card.open .topic-card-body {
  max-height: 480px;
  overflow-y: auto;
  padding: 16px 24px 24px;
}
.topic-card.open .topic-card-body::-webkit-scrollbar { width: 4px; }
.topic-card.open .topic-card-body::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 2px;
}
.topic-card-toggle {
  font-size: 12px;
  color: var(--text-dim);
  transition: transform var(--transition);
}
.topic-card.open .topic-card-toggle { transform: rotate(180deg); }

/* ===== LESSON LIST ===== */
.lesson-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.lesson-item {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 14px 16px;
  background: var(--surface2);
  border: 1px solid transparent;
  border-radius: 10px;
  cursor: pointer;
  transition: all var(--transition-slow);
  position: relative;
  overflow: hidden;
}
.lesson-item::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--accent);
  transform: scaleY(0);
  transition: transform var(--transition-slow);
}
.lesson-item:hover {
  border-color: rgba(0,255,136,0.2);
  transform: translateX(6px);
  background: rgba(0,255,136,0.03);
}
.lesson-item:hover::before { transform: scaleY(1); }
.lesson-item.completed {
  opacity: 0.75;
  border-color: rgba(0,255,136,0.15);
}
.lesson-item.completed::before {
  background: var(--accent);
  transform: scaleY(1);
}
.lesson-item.in-progress {
  border-color: rgba(0,187,255,0.3);
  background: rgba(0,187,255,0.03);
}
.lesson-item.in-progress::before {
  background: var(--accent2);
  transform: scaleY(1);
}
.lesson-status {
  font-size: 18px;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius);
  background: var(--surface);
  border: 1px solid var(--border);
  flex-shrink: 0;
}
.lesson-item.completed .lesson-status {
  border-color: var(--accent);
  background: rgba(0,255,136,0.1);
}
.lesson-item.in-progress .lesson-status {
  border-color: var(--accent2);
  background: rgba(0,187,255,0.1);
}
.lesson-info { flex: 1; min-width: 0; }
.lesson-title {
  font-weight: 600;
  font-size: 14px;
  color: var(--text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.lesson-item.completed .lesson-title { color: var(--text-dim); }
.lesson-meta {
  font-size: 11px;
  color: var(--text-dim);
  margin-top: 4px;
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
}
.lesson-xp {
  color: var(--xp-color);
  font-weight: 600;
  padding: 1px 8px;
  border-radius: var(--radius-sm);
  background: rgba(0,255,136,0.1);
}
.lesson-diff {
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.lesson-score {
  padding: 1px 8px;
  border-radius: var(--radius-sm);
  font-size: 11px;
  font-weight: 700;
}
.lesson-score.high { background: rgba(0,255,136,0.15); color: var(--accent); }
.lesson-score.medium { background: rgba(255,204,0,0.15); color: var(--gold); }
.lesson-score.low { background: rgba(255,68,68,0.15); color: var(--danger); }
.diff-beginner { background: rgba(0,255,136,0.15); color: var(--accent); }
.diff-intermediate { background: rgba(0,187,255,0.15); color: var(--accent2); }
.diff-advanced { background: rgba(255,102,204,0.15); color: var(--accent3); }
.diff-expert { background: rgba(255,68,68,0.15); color: var(--danger); }
.lesson-topic-badge { background: rgba(255,204,0,0.15); color: var(--gold); }
.lesson-arrow {
  color: var(--text-dim);
  font-size: 16px;
  transition: all var(--transition);
  flex-shrink: 0;
}
.lesson-item:hover .lesson-arrow {
  color: var(--accent);
  transform: translateX(4px);
}
.lesson-item .lesson-progress-mini {
  width: 60px;
  height: 4px;
  background: var(--border);
  border-radius: 2px;
  overflow: hidden;
  flex-shrink: 0;
}
.lesson-item .lesson-progress-mini .fill {
  height: 100%;
  border-radius: 2px;
  transition: width 0.5s;
}

/* Completed lessons bar */
.lesson-completed-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  background: rgba(0,255,136,0.05);
  border: 1px solid rgba(0,255,136,0.15);
  border-radius: 10px;
  cursor: pointer;
  transition: all var(--transition);
  margin-top: 4px;
}
.lesson-completed-bar:hover {
  background: rgba(0,255,136,0.1);
  border-color: rgba(0,255,136,0.3);
}
.lesson-completed-bar-left {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
}
.lesson-completed-icon { font-size: 16px; }
.lesson-completed-bar-right {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 12px;
}
.lesson-completed-toggle {
  font-size: 11px;
  color: var(--text-dim);
  transition: transform var(--transition);
}
.lesson-completed-bar.open .lesson-completed-toggle { transform: rotate(180deg); }
.lesson-completed-list {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-slow);
}
.lesson-completed-list.open {
  max-height: 350px;
  overflow-y: auto;
}
.lesson-completed-list.open::-webkit-scrollbar { width: 3px; }
.lesson-completed-list.open::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 2px;
}
.lesson-completed-list .lesson-item { margin-top: 8px; }

/* ===== LESSON VIEW ===== */
.lesson-view-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}
.lesson-view-back { cursor: pointer; font-size: 20px; }
.lesson-view-title { flex: 1; font-size: 20px; font-weight: 700; }
.lesson-view-content {
  line-height: 1.8;
  font-size: 15px;
}
.lesson-view-content h2 { margin: 24px 0 12px; color: var(--accent); font-size: 18px; }
.lesson-view-content h3 { margin: 20px 0 10px; color: var(--accent2); font-size: 16px; }
.lesson-view-content p { margin: 12px 0; }
.lesson-view-content ul, .lesson-view-content ol { margin: 12px 0; padding-left: 24px; }
.lesson-view-content li { margin: 6px 0; }
.lesson-view-content code {
  background: var(--surface2);
  padding: 2px 6px;
  border-radius: 3px;
  font-size: 13px;
  color: var(--accent3);
}
.lesson-view-content pre {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  overflow-x: auto;
  margin: 16px 0;
}
.lesson-view-content pre code {
  background: none;
  padding: 0;
  color: var(--text);
  font-size: 13px;
  line-height: 1.6;
}
.lesson-view-content blockquote {
  border-left: 3px solid var(--accent);
  padding-left: 16px;
  margin: 16px 0;
  color: var(--text-dim);
  font-style: italic;
}
.lesson-view-content img { max-width: 100%; border-radius: var(--radius); margin: 16px 0; }
.lesson-view-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
}
.lesson-view-content th, .lesson-view-content td {
  border: 1px solid var(--border);
  padding: 8px 12px;
  text-align: left;
}
.lesson-view-content th { background: var(--surface2); font-weight: 600; }
.lesson-view-content hr { border: none; border-top: 1px solid var(--border); margin: 24px 0; }
.lesson-actions {
  display: flex;
  gap: 12px;
  margin-top: 24px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}

/* ===== CODE CHALLENGE ===== */
.challenge-container {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  margin: 20px 0;
}
.challenge-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 16px;
  background: var(--surface2);
  border-bottom: 1px solid var(--border);
}
.challenge-title { font-weight: 600; font-size: 13px; }
.challenge-lang { font-size: 11px; color: var(--text-dim); }
.challenge-editor {
  width: 100%;
  min-height: 300px;
  padding: 16px;
  background: #0d0d20;
  border: 1px solid transparent;
  color: var(--text);
  font-family: 'Consolas', 'Monaco', monospace;
  font-size: 14px;
  line-height: 1.6;
  resize: vertical;
  tab-size: 2;
  transition: border-color 0.2s;
}
.challenge-editor:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
  border-color: var(--accent);
  box-shadow: 0 0 12px rgba(0,255,136,0.15);
}
.challenge-output {
  min-height: 80px;
  font-family: 'Consolas', 'Monaco', monospace;
  font-size: 13px;
  line-height: 1.5;
  background: #0d0d20;
  border-top: 1px solid var(--border);
}
.challenge-actions { display: flex; gap: 12px; padding: 16px; }
.challenge-toolbar {
  display: flex;
  flex-wrap: nowrap;
  overflow-x: auto;
  gap: 4px;
  padding: 8px 12px;
  background: var(--surface2);
  border-bottom: 1px solid var(--border);
  scrollbar-width: thin;
  -webkit-overflow-scrolling: touch;
}
.challenge-toolbar::-webkit-scrollbar { height: 3px; }
.challenge-toolbar::-webkit-scrollbar-thumb { background: var(--border); border-radius: 2px; }
.tb-btn {
  flex-shrink: 0;
  padding: 4px 10px;
  font-size: 11px;
  font-family: 'Consolas', 'Monaco', monospace;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.15s;
  touch-action: manipulation;
  min-height: 28px;
}
.tb-btn:active { background: var(--accent); color: #000; border-color: var(--accent); }
.tb-btn:hover { border-color: var(--accent); }
.tb-label {
  flex-shrink: 0;
  font-size: 10px;
  color: var(--text-dim);
  padding: 4px 6px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.editor-statusbar {
  display: flex;
  justify-content: space-between;
  padding: 4px 16px;
  font-size: 11px;
  color: var(--text-dim);
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  border-top: 1px solid var(--border);
  font-family: 'Consolas', 'Monaco', monospace;
}

/* ===== QUIZ ===== */
.quiz-container { margin: 20px 0; }
.quiz-question {
  padding: 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 12px;
}
.quiz-question-text { font-weight: 600; font-size: 14px; margin-bottom: 12px; }
.quiz-topic-badge {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 10px;
  font-size: 10px;
  font-weight: 700;
  background: rgba(0,187,255,0.12);
  color: var(--accent2);
  margin-right: 8px;
  vertical-align: middle;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.quiz-learn-more { display: inline-block; margin-top: 8px; font-size: 11px; color: var(--accent2); text-decoration: none; opacity: 0.85; }
.quiz-learn-more:hover { opacity: 1; text-decoration: underline; }
.quiz-learn-more-box { margin-top: 8px; border: 1px solid var(--border); border-radius: 6px; background: var(--surface2); overflow: hidden; }
.quiz-learn-more-box summary { cursor: pointer; padding: 8px 12px; font-size: 12px; font-weight: 600; color: var(--accent2); user-select: none; }
.quiz-learn-more-box summary:hover { background: var(--surface3); }
.quiz-learn-more-body { padding: 4px 12px 12px; border-top: 1px solid var(--border); }
.quiz-learn-more-answer { font-size: 11px; font-weight: 700; color: var(--accent); margin: 8px 0 4px; }
.quiz-learn-more-text { font-size: 12px; line-height: 1.5; color: var(--text); margin: 0; }
.quiz-options { display: flex; flex-direction: column; gap: 8px; }
.quiz-option {
  padding: 12px 16px;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  transition: all var(--transition);
}
.quiz-option:hover { border-color: var(--accent2); }
.quiz-option.selected {
  border-color: var(--accent2);
  background: rgba(0,187,255,0.1);
  box-shadow: 0 0 8px rgba(0,187,255,0.3);
}
.quiz-option.correct {
  border-color: var(--accent);
  background: rgba(0,255,136,0.1);
}
.quiz-option.incorrect {
  border-color: var(--danger);
  background: rgba(255,68,68,0.1);
}
.quiz-option .index {
  display: inline-block;
  width: 24px;
  height: 24px;
  line-height: 24px;
  text-align: center;
  background: var(--border);
  border-radius: 50%;
  margin-right: 12px;
  font-size: 12px;
}

/* ===== SKILL TREE ===== */
.skill-tree-container {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 16px;
  padding: 20px;
}
.skill-node {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 20px 12px;
  background: var(--surface);
  border: 2px solid var(--border);
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all var(--transition);
  position: relative;
  text-align: center;
}
.skill-node:hover { transform: translateY(-4px); }
.skill-node.unlocked {
  border-color: var(--accent);
  background: rgba(0,255,136,0.05);
}
.skill-node.locked { opacity: 0.5; cursor: not-allowed; }
.skill-node.locked:hover { transform: none; }
.skill-node.current {
  border-color: var(--gold);
  animation: glow 2s infinite;
}
.skill-node-icon { font-size: 32px; margin-bottom: 8px; }
.skill-node-name { font-size: 11px; font-weight: 600; }
.skill-node-status {
  position: absolute;
  top: 8px;
  right: 8px;
  font-size: 14px;
}
.skill-node-req {
  font-size: 9px;
  color: var(--text-dim);
  margin-top: 4px;
}

/* ===== ACHIEVEMENTS ===== */
.achievements-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 12px;
}
.achievement-card {
  padding: 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  text-align: center;
  transition: all var(--transition);
}
.achievement-card.unlocked { border-color: var(--gold); }
.achievement-card.locked { opacity: 0.4; }
.achievement-icon { font-size: 28px; margin-bottom: 8px; }
.achievement-name { font-size: 12px; font-weight: 600; margin-bottom: 4px; }
.achievement-desc { font-size: 10px; color: var(--text-dim); }

/* ===== LEADERBOARD ===== */
.leaderboard-table { width: 100%; border-collapse: collapse; }
.leaderboard-table th, .leaderboard-table td {
  padding: 12px 16px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}
.leaderboard-table th {
  font-size: 11px;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 1px;
}
.leaderboard-table tr:hover td { background: var(--surface2); }
.leaderboard-rank {
  font-weight: 800;
  font-size: 16px;
  width: 40px;
}
.rank-1 { color: var(--gold); }
.rank-2 { color: #c0c0c0; }
.rank-3 { color: #cd7f32; }
.leaderboard-user { font-weight: 600; }
.leaderboard-xp { color: var(--xp-color); }
.leaderboard-level { color: var(--accent2); }
.leaderboard-streak { color: var(--gold); }

/* Your rank card */
.your-rank-card {
  display: flex;
  align-items: center;
  gap: 12px;
  background: linear-gradient(135deg, rgba(255,215,0,0.08), rgba(255,136,0,0.08));
  border: 1px solid var(--gold);
  border-radius: 10px;
  padding: 14px 18px;
  margin-bottom: 16px;
}
.your-rank-icon { font-size: 32px; flex-shrink: 0; }
.your-rank-label { font-size: 16px; font-weight: 700; color: var(--gold); }

/* ===== PROFILE ===== */
.profile-header {
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 32px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  margin-bottom: 24px;
}
.profile-avatar {
  width: 80px;
  height: 80px;
  border: 3px solid var(--accent);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 40px;
  background: var(--surface2);
}
.profile-info { flex: 1; }
.profile-name { font-size: 24px; font-weight: 800; }
.profile-level { color: var(--accent2); font-size: 14px; margin-top: 4px; }
.profile-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin-bottom: 24px;
}
.activity-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(14px, 1fr));
  gap: 3px;
  margin: 12px 0;
}
.activity-cell {
  width: 14px;
  height: 14px;
  border-radius: 2px;
  background: var(--surface2);
}
.activity-cell.active { background: var(--accent); }
.activity-cell.many { background: var(--accent2); }

/* ===== NOTIFICATIONS ===== */
.notification {
  position: fixed;
  top: 20px;
  right: 20px;
  padding: 16px 24px;
  background: var(--surface);
  border: 1px solid var(--accent);
  border-radius: var(--radius);
  z-index: 1000;
  max-width: 400px;
  animation: slideUp 0.4s ease;
  box-shadow: var(--glow-accent);
}
.notification.hidden { display: none; }
.notification-title { font-weight: 700; margin-bottom: 4px; }
.notification-desc { font-size: 12px; color: var(--text-dim); }
.notification.xp { border-color: var(--xp-color); }
.notification.badge { border-color: var(--gold); }
.notification.error { border-color: var(--danger); }

/* ===== FLOATING POPUPS ===== */
#popup-container {
  position: fixed;
  bottom: 90px;
  right: 20px;
  z-index: 999;
  display: flex;
  flex-direction: column-reverse;
  gap: 10px;
  pointer-events: none;
}
.floating-popup {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  background: var(--surface);
  border: 1px solid var(--accent);
  border-radius: 10px;
  padding: 14px 16px;
  max-width: min(380px, calc(100vw - 40px));
  box-shadow: 0 4px 24px rgba(0,255,136,0.18);
  cursor: pointer;
  pointer-events: auto;
  opacity: 0;
  transform: translateX(40px) scale(0.95);
  transition: opacity 0.4s cubic-bezier(0.4,0,0.2,1), transform 0.4s cubic-bezier(0.4,0,0.2,1);
  animation: slideUp 0.4s ease;
}
.floating-popup.popup-visible {
  opacity: 1;
  transform: translateX(0) scale(1);
}
.floating-popup.popup-suggestion {
  border-color: var(--gold);
  box-shadow: 0 4px 24px rgba(255,215,0,0.2), 0 0 40px rgba(255,215,0,0.1);
}
.floating-popup:hover {
  border-color: var(--accent);
  box-shadow: 0 6px 32px rgba(0,255,136,0.25);
  transform: translateX(-4px) scale(1.02);
  transition: all 0.25s ease;
}
.floating-popup.popup-suggestion:hover {
  border-color: var(--gold);
  box-shadow: 0 6px 32px rgba(255,215,0,0.3);
}
.popup-icon {
  font-size: 22px;
  flex-shrink: 0;
  margin-top: 2px;
}
.popup-body { flex: 1; min-width: 0; }
.popup-title {
  font-weight: 700;
  font-size: 15px;
  margin-bottom: 2px;
  color: var(--accent);
}
.popup-suggestion .popup-title { color: var(--gold); }
.popup-desc {
  font-size: 13px;
  color: var(--text-dim);
  line-height: 1.5;
}
.popup-close {
  background: none;
  border: none;
  color: var(--text-dim);
  font-size: 18px;
  cursor: pointer;
  padding: 0 0 0 8px;
  flex-shrink: 0;
  line-height: 1;
}
.popup-close:hover { color: var(--danger); }

/* Popup expandable example */
.popup-example {
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  margin-top: 0;
  border-top: none;
  transition: max-height 0.4s cubic-bezier(0.4,0,0.2,1), opacity 0.35s ease, margin 0.35s ease;
}
.floating-popup.popup-expanded {
  max-width: min(460px, calc(100vw - 40px));
}
.popup-expanded .popup-example {
  max-height: 300px;
  opacity: 1;
  margin-top: 6px;
  padding-top: 6px;
  border-top: 1px solid rgba(0,255,136,0.15);
}
.popup-example-code {
  background: rgba(0,0,0,0.3);
  border-radius: 6px;
  padding: 6px 10px;
  font-family: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;
  font-size: 13px;
  line-height: 1.5;
  overflow-x: auto;
  white-space: pre;
  color: var(--text-dim);
  max-height: 200px;
  overflow-y: auto;
}

/* ===== REVIEWS SECTION ===== */
#hub-reviews-section { max-width: 600px; }
#hub-reviews-section .lesson-item {
  padding: 8px 12px;
  gap: 10px;
}
#hub-reviews-section .lesson-status {
  width: 24px; height: 24px;
  font-size: 14px;
}
#hub-reviews-section .lesson-title { font-size: 13px; }
#hub-reviews-section .lesson-meta { font-size: 10px; }
#hub-reviews-section .lesson-item .lesson-arrow { font-size: 14px; }

/* ===== FEEDBACK WIDGET ===== */
#feedback-widget { position: fixed; bottom: 36px; right: 20px; z-index: 999; }
.feedback-btn {
  width: 48px; height: 48px; border-radius: 50%;
  border: 1px solid var(--accent2);
  background: var(--surface); color: var(--accent2); font-size: 20px; cursor: pointer;
  box-shadow: var(--shadow); transition: all var(--transition);
  position: relative;
}
.feedback-btn::after {
  content: '💬 Feedback'; position: absolute; right: 56px; top: 50%; transform: translateY(-50%);
  background: var(--surface); color: var(--text); padding: 6px 12px; border-radius: 8px;
  font-size: 12px; white-space: nowrap; border: 1px solid var(--border);
  opacity: 0; pointer-events: none; transition: opacity 0.2s;
}
.feedback-btn:hover { background: var(--accent2); color: var(--bg); transform: scale(1.1); }
.feedback-btn:hover::after { opacity: 1; }
.feedback-btn:focus-visible { outline: 2px solid var(--accent2); outline-offset: 3px; }
.feedback-form {
  display: none; position: absolute; bottom: 60px; right: -10px; width: 360px;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 16px; box-shadow: var(--shadow-lg); z-index: 1000;
  transform-origin: bottom right; animation: feedback-expand 0.2s ease-out;
}
@keyframes feedback-expand {
  from { transform: scale(0.7); opacity: 0; }
  to { transform: scale(1); opacity: 1; }
}
.game-tip { margin-top:8px;border-radius:6px;font-size:12px;line-height:1.5;overflow:hidden; }
.game-tip-header {
  display:flex;align-items:center;gap:6px;padding:6px 10px;cursor:pointer;
  background:rgba(0,255,136,0.06);border-radius:6px;color:var(--accent2);
  transition:background 0.2s;user-select:none;
}
.game-tip-header:hover { background:rgba(0,255,136,0.12); }
.game-tip-header:focus-visible { outline:2px solid var(--accent2);outline-offset:2px; }
.game-tip-arrow { margin-left:auto;font-size:10px;transition:transform 0.2s; }
.game-tip-body {
  max-height:0;overflow:hidden;transition:max-height 0.3s ease,padding 0.3s ease;
  padding:0 10px;color:var(--text-dim);background:rgba(0,255,136,0.03);
}
.game-tip-open .game-tip-body { max-height:300px;padding:10px;overflow-y:auto; }
.game-tip-open .game-tip-header { border-radius:6px 6px 0 0; }
.feedback-form.visible { display: block; }
.feedback-header { font-weight: 700; font-size: 14px; margin-bottom: 8px; display: flex; justify-content: space-between; align-items: center; }
.feedback-header .feedback-hint { font-weight: 400; font-size: 10px; color: var(--text-dim); }
.feedback-stars { margin-bottom: 8px; font-size: 22px; cursor: pointer; }
.feedback-stars .star { color: var(--gold); transition: transform 0.2s; display: inline-block; }
.feedback-stars .star:hover { transform: scale(1.3); }
#feedback-message {
  width: 100%; min-height: 60px; padding: 8px; border: 1px solid var(--border);
  border-radius: 6px; background: #0d0d20; color: var(--text); font-size: 13px;
  resize: vertical; margin-bottom: 8px; box-sizing: border-box;
}
.feedback-actions { display: flex; gap: 8px; justify-content: flex-end; }
#feedback-status { font-size: 11px; margin-top: 6px; }

/* ===== FOOTER ===== */
#app-footer {
  position: relative; width: 100vw;
  left: 50%; right: 50%;
  margin-left: -50vw; margin-right: -50vw;
  margin-top: auto;
  display: flex; align-items: center; justify-content: center;
  padding: 4px; font-size: 11px; min-height: 28px;
  color: var(--text-dim); background: var(--surface);
  border-top: 1px solid var(--border); z-index: 100;
  letter-spacing: 0.3px;
}
#app-footer .debug-indicator {
  display: inline-block;
  padding: 0 8px;
  color: var(--accent3);
  font-weight: 700;
  animation: debugPulse 2s infinite;
}

/* ===== NAV TRANSITIONS ===== */
.screen-exit { animation: slideOutLeft 0.2s ease-in forwards; }
.screen-enter { animation: slideInRight 0.2s ease-out forwards; }

/* ===== TOP LOADING BAR ===== */
#top-loading-bar {
  position: fixed; top: 0; left: 0; height: 3px; z-index: 10000;
  background: linear-gradient(90deg, var(--accent), var(--accent2), var(--accent));
  background-size: 200% 100%;
  width: 0;
  transition: width 0.3s;
  pointer-events: none;
}
#top-loading-bar.active {
  width: 60%;
  animation: loadingSlide 1.5s ease infinite;
}
#top-loading-bar.done {
  width: 100%;
  opacity: 0;
  transition: width 0.3s, opacity 0.5s 0.2s;
}

/* ===== SYNTAX HIGHLIGHTING ===== */
.hl-preview {
  background: #0d0d20;
  border-bottom: 1px solid var(--border);
  padding: 12px 16px;
  font-size: 13px;
  line-height: 1.6;
  max-height: 120px;
  overflow: auto;
  scrollbar-width: thin;
}
.hl-preview-inner {
  margin: 0;
  font-family: 'Consolas', 'Monaco', monospace;
  font-size: 13px;
  line-height: 1.6;
  white-space: pre-wrap;
  word-wrap: break-word;
  background: transparent;
  border: none;
  padding: 0;
  color: var(--text);
}
.hl-preview-inner code { background: transparent; padding: 0; color: inherit; }
.hl-t { color: #569cd6; }
.hl-a { color: #9cdcfe; }
.hl-s { color: #ce9178; }
.hl-c { color: #6a9955; }
.hl-k { color: #c586c0; }
.hl-n { color: #b5cea8; }
.hl-d { color: #dcdcaa; }
.hl-b { color: #4fc1ff; }
.hl-e { color: #569cd6; }

/* ===== SUGGESTION STRIP ===== */
.suggestion-strip {
  display: none;
  flex-wrap: wrap;
  gap: 4px;
  padding: 6px 12px;
  background: var(--surface2);
  border-bottom: 1px solid var(--border);
}
.sug-btn {
  flex-shrink: 0;
  padding: 4px 10px;
  font-size: 11px;
  font-family: 'Consolas', 'Monaco', monospace;
  background: var(--surface);
  border: 1px solid var(--accent);
  border-radius: var(--radius-sm);
  color: var(--accent);
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.15s;
  touch-action: manipulation;
  min-height: 28px;
}
.sug-btn:active { background: var(--accent); color: #000; }
.sug-btn:hover { background: rgba(0,255,136,0.1); }
.sug-btn.active { background: var(--accent); color: #000; outline: 2px solid var(--accent2); }

/* ===== CONFETTI ===== */
.confetti-piece {
  position: fixed;
  width: 8px; height: 8px;
  border-radius: 2px;
  pointer-events: none;
  z-index: 9999;
}

/* ===== ONBOARDING CARD ===== */
.onboarding-card {
  display: flex;
  align-items: center;
  gap: 16px;
  background: linear-gradient(135deg, rgba(0,255,136,0.08), rgba(0,136,255,0.08));
  border: 1px solid var(--accent);
  border-radius: var(--radius-lg);
  padding: 20px 24px;
  margin-bottom: 20px;
}
.onboarding-icon { font-size: 40px; flex-shrink: 0; }
.onboarding-content { flex: 1; }
.onboarding-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 4px;
}
.onboarding-desc {
  font-size: 13px;
  color: var(--text-dim);
  margin-bottom: 10px;
}

.btn-start-now {
  animation: pulse 2s ease-in-out infinite, glow 2s ease-in-out infinite;
  box-shadow: 0 0 20px rgba(255,204,0,0.3);
}

/* ===== CODE / PRE ===== */
pre {
  background: #0d0d20;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 16px;
  overflow-x: auto;
  font-size: 13px;
  line-height: 1.6;
  margin: 16px 0;
}
pre code { background: none; padding: 0; font-size: inherit; }
code {
  background: rgba(255,255,255,0.06);
  padding: 2px 6px;
  border-radius: 3px;
  font-size: 13px;
  color: var(--accent2);
}
code.lang-css { color: #ce9178; }
code.lang-html { color: #ce9178; }
code.lang-js { color: #d4d4d4; }
code.lang-python { color: #d4d4d4; }
code.lang-bash { color: #d4d4d4; }
code.lang-sql { color: #d4d4d4; }
code.lang-json { color: #d4d4d4; }

/* ===== LOADING ===== */
.loading {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 60px;
  font-size: 14px;
  color: var(--text-dim);
}
.loading::after {
  content: '';
  width: 20px;
  height: 20px;
  border: 2px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin-left: 12px;
}

/* ===== RECOMMENDED LESSONS ===== */
.recommended-list { display: flex; flex-direction: column; gap: 8px; }
.recommended-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  transition: all var(--transition);
}
.recommended-item:hover { border-color: var(--accent); }
.recommended-item.weak-lesson { border-color: var(--warning); }
.recommended-icon { font-size: 18px; }
.recommended-info { flex: 1; }
.recommended-title { font-size: 13px; font-weight: 600; }
.recommended-meta { font-size: 11px; color: var(--text-dim); }
.recommended-xp { color: var(--xp-color); font-size: 11px; }

/* ===== SCROLLBAR ===== */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--accent); }

/* ===== UTILITY ===== */
.mb-2 { margin-bottom: 8px; }
.mb-4 { margin-bottom: 16px; }
.mb-8 { margin-bottom: 32px; }
.mt-2 { margin-top: 8px; }
.mt-4 { margin-top: 16px; }
.text-center { text-align: center; }
.text-dim { color: var(--text-dim); }
.text-accent { color: var(--accent); }
.text-gold { color: var(--gold); }
.text-sm { font-size: 12px; }
.text-xs { font-size: 10px; }
.flex { display: flex; }
.flex-col { flex-direction: column; }
.gap-2 { gap: 8px; }
.gap-4 { gap: 16px; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.w-full { width: 100%; }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.grid-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 16px; }

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
  #app { padding: 12px; }
  .intro-title { font-size: 20px; }
  .intro-features { grid-template-columns: 1fr; }
  #screen-hub .hub-grid { grid-template-columns: 1fr; }
  .hub-stats-row { grid-template-columns: repeat(2, 1fr); }
  .hud { flex-direction: column; gap: 12px; text-align: center; }
  .hud-left { flex-direction: column; }
  .profile-header { flex-direction: column; text-align: center; }
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
  .nav-bar { justify-content: center; }
  .nav-item { font-size: 13px; padding: 7px 10px; }
  .skill-tree-container { grid-template-columns: repeat(2, 1fr); }
  .challenge-editor {
    font-size: 16px !important;
    min-height: 200px;
    padding: 12px;
    resize: none;
  }
  .challenge-toolbar { padding: 6px 8px; gap: 3px; }
  .tb-btn { font-size: 10px; padding: 6px 8px; min-height: 32px; }
  .challenge-output { font-size: 14px; min-height: 60px; }
  .challenge-actions { flex-wrap: wrap; gap: 8px; }
  .challenge-actions .btn {
    flex: 1; min-width: 80px; text-align: center;
    font-size: 11px; padding: 10px 8px;
    overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
  }
  .challenge-container { margin: 12px 0; }
  .editor-statusbar { font-size: 10px; padding: 3px 12px; }
}

@media (max-width: 600px) {
  .nav-bar { flex-wrap: wrap; gap: 4px; padding: 8px 4px; }
  .nav-item { font-size: 13px; padding: 6px 10px; }
  .hud { flex-direction: column; gap: 8px; padding: 12px; }
  .hud-right { flex-wrap: wrap; justify-content: flex-start; }
  .screen { padding: 12px 8px; }
  .lesson-view-title { font-size: 18px; }
  .lesson-title { white-space: normal; overflow: visible; text-overflow: clip; }
  .card:has(.leaderboard-table) { overflow-x: auto; }
}

/* Tablet landscape (768-1024px) */
@media (max-width: 1024px) and (min-width: 769px) {
  #screen-hub .hub-grid { grid-template-columns: 1fr 280px; }
  .admin-grid { grid-template-columns: 1fr; }
  .grid-2 { grid-template-columns: 1fr 1fr; }
}

/* Large desktop (1440px+) */
@media (min-width: 1440px) {
  #app { max-width: 1400px; }
  #screen-hub .hub-grid { grid-template-columns: 1fr 320px; }
  .hub-stat-value { font-size: 26px; }
}

/* ===== ACTION GAME ===== */
.game-header {
  display: flex; justify-content: space-between; align-items: center;
  padding: 10px 16px; background: var(--surface);
  border: 1px solid var(--border); border-radius: var(--radius);
  margin-bottom: 12px; font-size: 14px; font-weight: 600;
  flex-wrap: wrap; gap: 8px;
}
.game-canvas-wrap {
  position: relative; border: 2px solid var(--border);
  border-radius: var(--radius-lg); overflow: hidden;
  background: #0a0a1a; max-width: 640px; margin: 0 auto;
}
#game-canvas { display: block; width: 100%; height: auto; aspect-ratio: 640/480; }
.game-overlay {
  position: absolute; inset: 0; background: rgba(0,0,0,0.8);
  display: flex; align-items: center; justify-content: center; z-index: 10;
}
.game-modal {
  background: var(--surface); border: 2px solid var(--accent);
  border-radius: var(--radius-lg); padding: 24px; max-width: 400px;
  margin: 16px; box-shadow: 0 0 40px rgba(0,255,136,0.2);
}
.game-modal-question {
  font-size: 16px; font-weight: 700; margin-bottom: 16px;
  color: var(--text); line-height: 1.5;
}
.game-modal-options {
  display: flex; flex-direction: column; gap: 8px;
}
.game-modal-options .btn {
  text-align: left; font-family: inherit; font-size: 13px;
  padding: 10px 16px; text-transform: none; letter-spacing: normal;
  transition: all 0.15s;
}
.game-modal-options .btn:hover {
  background: var(--accent); color: var(--bg);
}
.game-modal-options .btn.active {
  background: var(--accent); color: var(--bg);
  box-shadow: 0 0 15px rgba(0,255,136,0.4);
  transform: translateX(4px);
}
.game-modal-options .correct-answer {
  border-color: var(--accent) !important;
  background: rgba(0,255,136,0.15) !important;
  color: var(--accent) !important;
}
.game-modal-options .wrong-answer {
  border-color: var(--danger) !important;
  background: rgba(255,68,68,0.15) !important;
  color: var(--danger) !important;
}
.edu-close-btn {
  position: absolute; top: 8px; right: 8px; z-index: 20;
  cursor: pointer; background: var(--surface2);
  border: 1px solid var(--border); color: var(--text-dim);
  padding: 6px 12px; border-radius: var(--radius-sm);
  font-size: 12px; font-family: inherit;
  transition: all var(--transition);
}
.edu-close-btn:hover { border-color: var(--accent); color: var(--accent); }
.edu-close-btn:focus-visible { outline: 2px solid var(--accent); }
.game-hint {
  text-align: center; font-size: 11px; color: var(--text-dim);
  margin-top: 8px; padding: 4px;
}
.game-over-screen {
  text-align: center; padding: 60px 20px;
}
.game-over-icon { font-size: 64px; margin-bottom: 12px; }
.game-over-title {
  font-family: 'Press Start 2P', monospace; font-size: 24px;
  color: var(--accent); margin-bottom: 12px;
}
.game-over-stats {
  font-size: 18px; color: var(--gold); font-weight: 700; margin-bottom: 8px;
}
.game-over-sub { font-size: 14px; color: var(--text-dim); }