:root {
  /* Основные цвета */
  --bg: #071321;
  --panel: #0d2238;
  --panel2: #102b45;
  --line: #17476a;
  
  /* Акцентные цвета */
  --cyan: #20d9d2;
  --blue: #00bfff;
  --orange: #ff9f43;
  --purple: #a78bfa;
  --green: #20d6a1;
  --red: #ff7272;
  
  /* Текст */
  --text: #f3f8ff;
  --muted: #91a9bf;
  
  /* Радиусы */
  --radius: 20px;
  --radius-sm: 12px;
  --radius-lg: 26px;
  
  /* Тени */
  --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 18px 55px rgba(0, 0, 0, 0.2);
  --shadow-glow: 0 0 28px rgba(0, 191, 255, 0.19);
  
  /* Отступы */
  --spacing-xs: 8px;
  --spacing-sm: 12px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
}

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

body {
  margin: 0;
  background: radial-gradient(ellipse at 20% 0%, #10304b 0%, var(--bg) 48%, #050c16 100%);
  background-attachment: fixed;
  color: var(--text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, 'Segoe UI', sans-serif;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

button {
  font: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

a {
  color: inherit;
  text-decoration: none;
}

/* Scrollbar styling */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--panel);
}

::-webkit-scrollbar-thumb {
  background: var(--line);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--cyan);
}

/* Анимации */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

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

@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.5;
  }
}

@keyframes fillBar {
  from {
    width: 0;
  }
}

/* Учитываем настройки системы об уменьшении анимации */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* Utility classes */
.text-center {
  text-align: center;
}

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

.text-small {
  font-size: 12px;
}

.hidden {
  display: none !important;
}

.loading {
  animation: pulse 1.5s ease-in-out infinite;
}

/* Layout Styles */
.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-lg);
  background: rgba(13, 34, 56, 0.6);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 100;
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.logo {
  width: 48px;
  height: 48px;
  display: grid;
  place-items: center;
  border-radius: 16px;
  background: linear-gradient(145deg, var(--cyan), var(--blue));
  color: #062033;
  font-size: 25px;
  box-shadow: var(--shadow-glow);
}

.brand-text h1 {
  font-size: 17px;
  margin: 0;
  font-weight: 700;
}

.brand-text p {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 12px;
}

.user-info {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.xp-display {
  background: linear-gradient(90deg, rgba(10, 140, 170, 0.2), rgba(13, 43, 67, 0.5));
  padding: 8px 14px;
  border-radius: 999px;
  border: 1px solid var(--line);
  font-weight: 600;
  color: var(--cyan);
  font-size: 14px;
}

/* Sidebar */
.sidebar {
  position: fixed;
  left: 0;
  top: 80px;
  width: 240px;
  height: calc(100vh - 80px);
  background: rgba(9, 26, 43, 0.87);
  border-right: 1px solid var(--line);
  padding: var(--spacing-md);
  overflow-y: auto;
  z-index: 50;
}

.user-card {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm);
  margin-bottom: var(--spacing-md);
  border-bottom: 1px solid var(--line);
  padding-bottom: var(--spacing-md);
}

.avatar {
  width: 43px;
  height: 43px;
  border-radius: 15px;
  background: linear-gradient(145deg, #173f5e, #0d718b);
  display: grid;
  place-items: center;
  font-size: 24px;
  border: 1px solid #24779b;
}

.user-details strong {
  display: block;
  font-size: 13px;
  margin-bottom: 4px;
}

.user-details small {
  color: var(--muted);
  font-size: 11px;
}

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

.nav-link {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  width: 100%;
  padding: var(--spacing-sm);
  border-radius: 13px;
  background: transparent;
  color: var(--muted);
  transition: all 0.2s;
  text-align: left;
  font-size: 13px;
}

.nav-link .icon {
  width: 22px;
  text-align: center;
  font-size: 17px;
}

.nav-link:hover,
.nav-link.active {
  background: linear-gradient(90deg, rgba(10, 140, 170, 0.2), rgba(13, 43, 67, 0.3));
  color: var(--cyan);
}

/* Main Content */
.main-content {
  margin-left: 240px;
  padding: var(--spacing-lg);
  min-height: calc(100vh - 80px);
  padding-bottom: 100px;
}

/* Mobile Navigation */
.mobile-nav {
  display: none;
  position: fixed;
  bottom: 8px;
  left: 8px;
  right: 8px;
  background: rgba(7, 24, 39, 0.95);
  backdrop-filter: blur(16px);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 8px;
  z-index: 1000;
  justify-content: space-around;
  gap: 4px;
}

.mobile-nav-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: 8px 12px;
  color: var(--muted);
  font-size: 10px;
  background: transparent;
  border-radius: 12px;
  transition: all 0.2s;
  flex: 1;
}

.mobile-nav-btn .icon {
  font-size: 20px;
}

.mobile-nav-btn.active {
  color: var(--cyan);
  background: rgba(32, 217, 210, 0.1);
}

/* Page Styles */
.page {
  animation: fadeIn 0.3s ease;
}

.page-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.page-header h2 {
  font-size: 28px;
  margin: 0 0 8px;
  letter-spacing: -0.5px;
}

.subtitle {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.5;
}

.tag {
  display: inline-block;
  border-radius: 999px;
  background: rgba(11, 67, 82, 0.8);
  color: var(--cyan);
  padding: 6px 12px;
  font-size: 11px;
  font-weight: 700;
  white-space: nowrap;
}

/* Stats Grid */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

.stat-card {
  background: linear-gradient(145deg, #102a42, #0a1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-md);
  transition: transform 0.2s, border-color 0.2s;
}

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

.stat-label {
  font-size: 12px;
  color: var(--muted);
  margin-bottom: 8px;
}

.stat-value {
  font-size: 28px;
  font-weight: 700;
  margin: 8px 0;
}

.stat-subtitle {
  font-size: 11px;
  color: var(--cyan);
  margin-top: 4px;
}

.progress-bar {
  height: 7px;
  border-radius: 99px;
  background: #19384e;
  overflow: hidden;
  margin: 8px 0;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--cyan), var(--blue));
  border-radius: 99px;
  transition: width 0.5s ease;
  animation: fillBar 1s ease;
}

/* Section Header */
.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin: var(--spacing-xl) 0 var(--spacing-md);
}

.section-header h3 {
  font-size: 18px;
  margin: 0;
}

/* Quick Actions Grid */
.quick-actions-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

.quick-action {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  background: linear-gradient(145deg, #102b43, #0b1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-md);
  text-align: left;
  color: var(--text);
  transition: all 0.2s;
  min-height: 90px;
}

.quick-action:hover {
  border-color: var(--cyan);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.quick-icon {
  font-size: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 50px;
  height: 50px;
  flex-shrink: 0;
}

.quick-content {
  flex: 1;
}

.quick-title {
  font-weight: 600;
  font-size: 14px;
  margin-bottom: 4px;
}

.quick-subtitle {
  font-size: 11px;
  color: var(--muted);
}

/* Progress Overview */
.progress-overview {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

.progress-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  background: linear-gradient(145deg, #102a42, #0a1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-md);
}

.progress-icon {
  font-size: 28px;
  width: 50px;
  height: 50px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.progress-details {
  flex: 1;
}

.progress-title {
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 6px;
}

.progress-stats {
  font-size: 20px;
  font-weight: 600;
}

.progress-current {
  color: var(--cyan);
}

.progress-separator {
  color: var(--muted);
  margin: 0 4px;
}

.progress-total {
  color: var(--muted);
}

.progress-bar-small {
  width: 120px;
  height: 6px;
  border-radius: 99px;
  background: #19384e;
  overflow: hidden;
}

/* Motivation Card */
.motivation-card {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
  background: linear-gradient(110deg, #10334d, #10223a);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-lg);
  margin-top: var(--spacing-xl);
}

.motivation-icon {
  font-size: 48px;
  filter: drop-shadow(0 4px 12px rgba(255, 159, 67, 0.25));
}

.motivation-content h3 {
  margin: 0 0 8px;
  font-size: 18px;
  color: var(--orange);
}

.motivation-content p {
  margin: 0;
  color: var(--muted);
  line-height: 1.6;
}

/* Loading Screen */
.loading-screen {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  background: var(--bg);
}

.loader {
  text-align: center;
}

.atom-icon {
  font-size: 64px;
  animation: pulse 2s ease-in-out infinite;
  margin-bottom: var(--spacing-md);
}

/* Toast */
.toast {
  position: fixed;
  bottom: 22px;
  left: 50%;
  transform: translate(-50%, 20px);
  background: #10384a;
  border: 1px solid #25869a;
  padding: 12px 18px;
  border-radius: 13px;
  opacity: 0;
  pointer-events: none;
  transition: all 0.25s;
  z-index: 10000;
  font-size: 13px;
  box-shadow: 0 10px 35px rgba(0, 0, 0, 0.4);
  max-width: 90%;
}

.toast.show {
  opacity: 1;
  transform: translate(-50%, 0);
}

/* Responsive */
@media (max-width: 768px) {
  .app-header {
    padding: var(--spacing-md);
  }
  
  .brand-text h1 {
    font-size: 14px;
  }
  
  .brand-text p {
    display: none;
  }
  
  .sidebar {
    display: none;
  }
  
  .main-content {
    margin-left: 0;
    padding: var(--spacing-md);
    padding-bottom: 80px;
  }
  
  .mobile-nav {
    display: flex;
  }
  
  .stats-grid {
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: var(--spacing-sm);
  }
  
  .stat-card {
    padding: var(--spacing-sm);
  }
  
  .stat-value {
    font-size: 22px;
  }
  
  .quick-actions-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-sm);
  }
  
  .quick-action {
    flex-direction: column;
    text-align: center;
    min-height: 120px;
  }
  
  .motivation-card {
    flex-direction: column;
    text-align: center;
  }
  
  .page-header {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 480px) {
  .page-header h2 {
    font-size: 22px;
  }
  
  .stats-grid {
    grid-template-columns: 1fr;
  }
  
  .progress-bar-small {
    width: 80px;
  }
}
/* Additional styles for knowledge, games, leaderboard, achievements, quests, profile pages */

/* Knowledge Page */
.sections-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

.section-card {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  background: linear-gradient(145deg, #102b43, #0b1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-md);
  text-align: left;
  transition: all 0.2s;
}

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

.section-icon {
  font-size: 40px;
  width: 60px;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.section-content {
  flex: 1;
}

.section-title {
  font-size: 16px;
  font-weight: 600;
  margin: 0 0 4px;
}

.section-description {
  font-size: 12px;
  color: var(--muted);
  margin: 0 0 8px;
}

.section-progress {
  margin-top: 8px;
}

.progress-text {
  font-size: 11px;
  color: var(--muted);
  margin-bottom: 4px;
}

/* Topics List */
.topics-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.topic-card {
  background: linear-gradient(145deg, #0d2238, #0a1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-md);
  text-align: left;
  transition: all 0.2s;
  width: 100%;
}

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

.topic-card.completed {
  border-color: var(--green);
}

.topic-header {
  display: flex;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-sm);
}

.topic-icon {
  font-size: 24px;
  flex-shrink: 0;
}

.topic-info {
  flex: 1;
}

.topic-title {
  font-size: 16px;
  font-weight: 600;
  margin: 0 0 4px;
}

.topic-description {
  font-size: 13px;
  color: var(--muted);
  margin: 0;
}

.topic-footer {
  display: flex;
  gap: var(--spacing-md);
  align-items: center;
  font-size: 12px;
  color: var(--muted);
  margin-top: var(--spacing-sm);
}

.topic-xp {
  color: var(--cyan);
  font-weight: 600;
}

.topic-score {
  color: var(--green);
}

/* Topic Detail */
.topic-detail {
  max-width: 800px;
  margin: 0 auto;
}

.topic-detail-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-lg);
}

.topic-theory {
  background: linear-gradient(145deg, #0d2238, #0a1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
  line-height: 1.7;
}

.topic-theory h1 {
  font-size: 24px;
  margin: 0 0 var(--spacing-md);
}

.topic-theory h2 {
  font-size: 20px;
  margin: var(--spacing-lg) 0 var(--spacing-sm);
}

.topic-theory h3 {
  font-size: 18px;
  margin: var(--spacing-md) 0 var(--spacing-sm);
}

.topic-theory p {
  margin: var(--spacing-sm) 0;
}

.topic-theory ul {
  margin: var(--spacing-sm) 0;
  padding-left: var(--spacing-lg);
}

.formulas-section,
.examples-section {
  margin-bottom: var(--spacing-lg);
}

.formula-card {
  background: linear-gradient(145deg, #081d30, #0a1220);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-md);
}

.formula {
  font-family: 'Georgia', serif;
  font-size: 24px;
  color: var(--cyan);
  text-align: center;
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-sm);
}

.formula-description {
  text-align: center;
  color: var(--muted);
  font-size: 13px;
}

.example-card {
  background: linear-gradient(145deg, #102a42, #0a1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-md);
}

.example-card h4 {
  margin: 0 0 var(--spacing-sm);
  color: var(--orange);
}

/* Test View */
.test-detail {
  max-width: 800px;
  margin: 0 auto;
}

.test-header {
  margin-bottom: var(--spacing-lg);
}

.test-progress {
  margin-top: var(--spacing-sm);
  font-size: 13px;
  color: var(--muted);
}

.question-card {
  background: linear-gradient(145deg, #0d2238, #0a1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
}

.question-number {
  font-size: 12px;
  color: var(--muted);
  margin-bottom: var(--spacing-sm);
}

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

.answers-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.answer-option {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md);
  background: #0c2237;
  border: 1px solid var(--line);
  border-radius: 14px;
  text-align: left;
  transition: all 0.2s;
}

.answer-option:hover {
  border-color: var(--cyan);
}

.answer-option.selected {
  border-color: var(--cyan);
  background: rgba(32, 217, 210, 0.1);
}

.answer-letter {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #16364e;
  border-radius: 8px;
  font-weight: 700;
  font-size: 14px;
  flex-shrink: 0;
}

.answer-text {
  flex: 1;
}

/* Test Result */
.test-result {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
}

.result-header {
  padding: var(--spacing-xl);
  border-radius: var(--radius);
  margin-bottom: var(--spacing-lg);
}

.result-header.passed {
  background: linear-gradient(145deg, rgba(32, 214, 161, 0.2), rgba(32, 214, 161, 0.05));
  border: 1px solid var(--green);
}

.result-header.failed {
  background: linear-gradient(145deg, rgba(255, 114, 114, 0.2), rgba(255, 114, 114, 0.05));
  border: 1px solid var(--red);
}

.result-icon {
  font-size: 64px;
  margin-bottom: var(--spacing-md);
}

.result-score {
  font-size: 48px;
  font-weight: 700;
  margin: var(--spacing-md) 0;
}

.result-message {
  font-size: 16px;
  line-height: 1.6;
}

.achievements-unlocked {
  background: linear-gradient(145deg, rgba(255, 159, 67, 0.2), rgba(255, 159, 67, 0.05));
  border: 1px solid var(--orange);
  border-radius: var(--radius);
  padding: var(--spacing-md);
  margin-top: var(--spacing-md);
}

.achievement-badge {
  display: inline-block;
  background: var(--orange);
  color: var(--bg);
  padding: 4px 12px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 700;
  margin: 4px;
}

.result-actions {
  display: flex;
  gap: var(--spacing-sm);
  justify-content: center;
  margin-top: var(--spacing-lg);
}

/* Games Page */
.games-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-md);
}

.game-card {
  background: linear-gradient(145deg, #102b43, #0b1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-lg);
  text-align: center;
  transition: all 0.2s;
}

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

.game-icon {
  font-size: 48px;
  margin-bottom: var(--spacing-md);
}

.game-title {
  font-size: 18px;
  margin: 0 0 var(--spacing-sm);
}

.game-description {
  font-size: 13px;
  color: var(--muted);
  line-height: 1.5;
  margin-bottom: var(--spacing-md);
}

.game-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-md);
  font-size: 12px;
}

.game-difficulty {
  padding: 4px 8px;
  border-radius: 4px;
  font-weight: 600;
}

.game-difficulty.easy {
  background: rgba(32, 214, 161, 0.2);
  color: var(--green);
}

.game-difficulty.medium {
  background: rgba(255, 159, 67, 0.2);
  color: var(--orange);
}

.game-difficulty.hard {
  background: rgba(255, 114, 114, 0.2);
  color: var(--red);
}

.game-reward {
  color: var(--cyan);
  font-weight: 600;
}

/* Game View */
.game-view {
  max-width: 800px;
  margin: 0 auto;
}

.game-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-lg);
}

.game-instructions {
  background: linear-gradient(145deg, #0d2238, #0a1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
  text-align: center;
}

.game-controls {
  background: linear-gradient(145deg, #0d2238, #0a1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-lg);
  margin: var(--spacing-lg) 0;
}

.control-group {
  margin-bottom: var(--spacing-md);
}

.control-group label {
  display: block;
  margin-bottom: var(--spacing-sm);
  font-weight: 600;
}

.control-group input[type="number"],
.control-group input[type="range"] {
  width: 100%;
  padding: var(--spacing-sm);
  background: #0a1d30;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--text);
  font-size: 16px;
}

.resistor-options {
  display: flex;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

.resistor-btn {
  padding: var(--spacing-sm) var(--spacing-md);
  background: #0c2237;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--text);
  transition: all 0.2s;
}

.resistor-btn:hover {
  border-color: var(--cyan);
}

.resistor-btn.selected {
  border-color: var(--cyan);
  background: rgba(32, 217, 210, 0.1);
}

.game-result {
  margin-top: var(--spacing-lg);
}

.result-card {
  background: linear-gradient(145deg, #0d2238, #0a1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-xl);
  text-align: center;
}

.result-card.success {
  border-color: var(--green);
}

.result-card.failure {
  border-color: var(--red);
}

/* Leaderboard Page */
.leaderboard-filters {
  display: flex;
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
  flex-wrap: wrap;
}

.filter-group {
  flex: 1;
  min-width: 200px;
}

.filter-group label {
  display: block;
  margin-bottom: var(--spacing-sm);
  font-weight: 600;
  font-size: 13px;
}

.filter-buttons {
  display: flex;
  gap: var(--spacing-xs);
  flex-wrap: wrap;
}

.filter-btn {
  padding: var(--spacing-sm) var(--spacing-md);
  background: #0c2237;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--text);
  font-size: 13px;
  transition: all 0.2s;
}

.filter-btn:hover {
  border-color: var(--cyan);
}

.filter-btn.active {
  border-color: var(--cyan);
  background: rgba(32, 217, 210, 0.1);
  color: var(--cyan);
}

.user-rank-card {
  background: linear-gradient(110deg, #10334d, #10223a);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
}

.rank-icon {
  font-size: 48px;
}

.rank-details {
  flex: 1;
}

.rank-label {
  font-size: 12px;
  color: var(--muted);
}

.rank-value {
  font-size: 32px;
  font-weight: 700;
  color: var(--cyan);
}

.rank-stats {
  display: flex;
  gap: var(--spacing-lg);
}

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

.rank-stat-label {
  display: block;
  font-size: 11px;
  color: var(--muted);
  margin-bottom: 4px;
}

.rank-stat-value {
  display: block;
  font-size: 20px;
  font-weight: 700;
}

.leaderboard-table {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.leaderboard-entry {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  background: linear-gradient(145deg, #0d2238, #0a1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-md);
  transition: all 0.2s;
}

.leaderboard-entry:hover {
  border-color: var(--cyan);
  transform: translateY(-1px);
}

.leaderboard-entry.current-user {
  border-color: var(--orange);
  background: linear-gradient(145deg, rgba(255, 159, 67, 0.1), rgba(255, 159, 67, 0.05));
}

.entry-rank {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 50px;
  flex-shrink: 0;
}

.rank-number {
  font-size: 24px;
  font-weight: 700;
}

.rank-medal {
  font-size: 20px;
}

.entry-user {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  flex: 1;
}

.user-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: linear-gradient(145deg, #173f5e, #0d718b);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
}

.user-name {
  font-weight: 600;
  font-size: 15px;
}

.user-meta {
  font-size: 12px;
  color: var(--muted);
  margin-top: 2px;
}

.entry-stats {
  display: flex;
  gap: var(--spacing-lg);
  align-items: center;
}

.entry-xp,
.entry-topics {
  text-align: center;
}

.xp-value,
.topics-value {
  display: block;
  font-size: 18px;
  font-weight: 700;
  color: var(--cyan);
}

.xp-label,
.topics-label {
  display: block;
  font-size: 11px;
  color: var(--muted);
}

/* Achievements Page */
.achievements-progress {
  background: linear-gradient(145deg, #0d2238, #0a1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-lg);
  margin-bottom: var(--spacing-xl);
  text-align: center;
}

.achievements-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

.achievement-card {
  background: linear-gradient(145deg, #122b42, #091c2c);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-md);
  text-align: center;
  transition: all 0.2s;
}

.achievement-card.unlocked {
  border-color: var(--orange);
}

.achievement-card.locked {
  opacity: 0.6;
}

.achievement-icon {
  font-size: 48px;
  margin-bottom: var(--spacing-sm);
  filter: drop-shadow(0 4px 12px rgba(255, 159, 67, 0.25));
}

.locked-icon {
  filter: grayscale(100%) opacity(0.5);
}

.achievement-title {
  font-size: 14px;
  font-weight: 600;
  margin: 0 0 var(--spacing-xs);
}

.achievement-description {
  font-size: 11px;
  color: var(--muted);
  line-height: 1.4;
  margin: 0 0 var(--spacing-sm);
}

.achievement-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 11px;
  margin-top: var(--spacing-sm);
  padding-top: var(--spacing-sm);
  border-top: 1px solid var(--line);
}

.achievement-xp {
  color: var(--cyan);
  font-weight: 600;
}

.achievement-date {
  color: var(--muted);
}

.achievement-status {
  color: var(--muted);
}

/* Quests Page */
.quests-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.quest-card {
  display: flex;
  gap: var(--spacing-lg);
  background: linear-gradient(100deg, #102a42, #0a1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-lg);
  transition: all 0.2s;
}

.quest-card.completed {
  border-color: var(--green);
}

.quest-card.locked {
  opacity: 0.6;
}

.quest-icon {
  font-size: 64px;
  flex-shrink: 0;
}

.quest-content {
  flex: 1;
}

.quest-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-sm);
}

.quest-title {
  font-size: 20px;
  margin: 0;
}

.quest-category {
  font-size: 11px;
  padding: 4px 8px;
  background: rgba(32, 217, 210, 0.2);
  color: var(--cyan);
  border-radius: 4px;
}

.quest-description {
  font-size: 14px;
  color: var(--muted);
  margin: 0 0 var(--spacing-sm);
}

.quest-story {
  font-size: 13px;
  font-style: italic;
  color: var(--muted);
  padding: var(--spacing-sm);
  background: rgba(255, 159, 67, 0.1);
  border-left: 3px solid var(--orange);
  border-radius: 4px;
  margin-bottom: var(--spacing-md);
}

.quest-progress {
  margin: var(--spacing-md) 0;
}

.progress-header {
  display: flex;
  justify-content: space-between;
  margin-bottom: var(--spacing-xs);
  font-size: 12px;
}

.quest-steps {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
  margin: var(--spacing-md) 0;
}

.quest-step {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm);
  background: rgba(23, 71, 106, 0.2);
  border-radius: 8px;
  font-size: 13px;
}

.quest-step.completed {
  background: rgba(32, 214, 161, 0.1);
  color: var(--green);
}

.quest-step.active {
  background: rgba(32, 217, 210, 0.2);
  border: 1px solid var(--cyan);
}

.step-indicator {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--line);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 12px;
  flex-shrink: 0;
}

.quest-step.completed .step-indicator {
  background: var(--green);
}

.quest-step.active .step-indicator {
  background: var(--cyan);
  color: var(--bg);
}

.quest-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: var(--spacing-md);
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--line);
}

.quest-reward {
  color: var(--orange);
  font-weight: 600;
}

.quest-status {
  font-size: 12px;
  padding: 4px 12px;
  border-radius: 999px;
}

.quest-status.completed {
  background: rgba(32, 214, 161, 0.2);
  color: var(--green);
}

.quest-status.locked {
  color: var(--muted);
}

/* Profile Page */
.profile-card {
  background: linear-gradient(110deg, #10334d, #10223a);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-xl);
  margin-bottom: var(--spacing-xl);
  display: flex;
  gap: var(--spacing-lg);
  align-items: center;
  position: relative;
}

.profile-avatar-large {
  width: 80px;
  height: 80px;
  border-radius: 24px;
  background: linear-gradient(145deg, #155675, #0a273d);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 48px;
  border: 2px solid var(--cyan);
  flex-shrink: 0;
}

.profile-info {
  flex: 1;
}

.profile-name {
  font-size: 24px;
  margin: 0 0 4px;
}

.profile-meta {
  font-size: 14px;
  color: var(--muted);
  margin: 0 0 4px;
}

.profile-level-title {
  font-size: 16px;
  color: var(--cyan);
  font-weight: 600;
}

.profile-xp-bar {
  margin-top: var(--spacing-md);
}

.xp-bar-label {
  display: flex;
  justify-content: space-between;
  font-size: 13px;
  margin-bottom: var(--spacing-xs);
}

.xp-to-next {
  font-size: 11px;
  color: var(--muted);
  margin-top: var(--spacing-xs);
}

.profile-stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

.profile-stat-card {
  background: linear-gradient(145deg, #0d2238, #0a1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-md);
  text-align: center;
}

.stat-icon {
  font-size: 32px;
  margin-bottom: var(--spacing-sm);
}

.stat-value {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 4px;
}

.stat-label {
  font-size: 13px;
  color: var(--muted);
}

.stat-total {
  font-size: 11px;
  color: var(--muted);
  margin-top: 4px;
}

/* Collection */
.collection-preview {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-xl);
}

.collection-item {
  background: linear-gradient(145deg, #0d2238, #0a1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: var(--spacing-sm);
  text-align: center;
  aspect-ratio: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}

.collection-item.obtained {
  border-color: var(--cyan);
}

.collection-item.locked {
  opacity: 0.5;
}

.item-icon {
  font-size: 32px;
  margin-bottom: var(--spacing-xs);
}

.item-name {
  font-size: 11px;
  font-weight: 600;
  margin-bottom: 4px;
}

.item-rarity {
  font-size: 9px;
  padding: 2px 6px;
  border-radius: 4px;
}

.item-rarity.common {
  background: rgba(145, 169, 191, 0.2);
  color: var(--muted);
}

.item-rarity.rare {
  background: rgba(32, 217, 210, 0.2);
  color: var(--cyan);
}

.item-rarity.epic {
  background: rgba(167, 139, 250, 0.2);
  color: var(--purple);
}

.item-rarity.legendary {
  background: rgba(255, 159, 67, 0.2);
  color: var(--orange);
}

/* Settings */
.settings-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-xl);
}

.setting-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: linear-gradient(145deg, #0d2238, #0a1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-md);
}

.setting-label {
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 4px;
}

.setting-value {
  font-size: 13px;
  color: var(--muted);
}

/* Modal */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.8);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10000;
  padding: var(--spacing-md);
}

.modal-content {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  max-width: 500px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
}

.modal-content.large {
  max-width: 800px;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-lg);
  border-bottom: 1px solid var(--line);
}

.modal-header h3 {
  margin: 0;
  font-size: 20px;
}

.modal-close {
  font-size: 32px;
  line-height: 1;
  color: var(--muted);
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  width: 32px;
  height: 32px;
}

.modal-close:hover {
  color: var(--text);
}

.modal-body {
  padding: var(--spacing-lg);
}

.modal-body label {
  display: block;
  margin-bottom: var(--spacing-xs);
  font-weight: 600;
}

.modal-body input[type="text"] {
  width: 100%;
  padding: var(--spacing-sm);
  background: #0a1d30;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--text);
  font-size: 16px;
  margin-bottom: var(--spacing-sm);
}

.input-hint {
  font-size: 12px;
  color: var(--muted);
  margin-bottom: var(--spacing-md);
}

.error-message {
  color: var(--red);
  font-size: 13px;
  padding: var(--spacing-sm);
  background: rgba(255, 114, 114, 0.1);
  border-radius: 8px;
  margin-top: var(--spacing-sm);
}

.modal-footer {
  display: flex;
  gap: var(--spacing-sm);
  justify-content: flex-end;
  padding: var(--spacing-lg);
  border-top: 1px solid var(--line);
}

/* Responsive */
@media (max-width: 768px) {
  .sections-grid {
    grid-template-columns: 1fr;
  }
  
  .topic-card {
    padding: var(--spacing-sm);
  }
  
  .games-grid {
    grid-template-columns: 1fr;
  }
  
  .leaderboard-filters {
    flex-direction: column;
  }
  
  .user-rank-card {
    flex-direction: column;
    text-align: center;
  }
  
  .entry-stats {
    flex-direction: column;
    gap: var(--spacing-xs);
  }
  
  .achievements-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .quest-card {
    flex-direction: column;
    text-align: center;
  }
  
  .profile-card {
    flex-direction: column;
    text-align: center;
  }
  
  .profile-stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .collection-preview {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 480px) {
  .filter-buttons {
    width: 100%;
  }
  
  .filter-btn {
    flex: 1;
    text-align: center;
  }
  
  .achievements-grid {
    grid-template-columns: 1fr;
  }
  
  .profile-stats-grid {
    grid-template-columns: 1fr;
  }
}

/* Back button */
.back-button {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-md);
  background: transparent;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--muted);
  font-size: 14px;
  margin-bottom: var(--spacing-md);
  transition: all 0.2s;
}

.back-button:hover {
  border-color: var(--cyan);
  color: var(--cyan);
}

/* Empty states */
.empty-state {
  text-align: center;
  padding: var(--spacing-xl);
  color: var(--muted);
}

/* About section */
.about-section {
  background: linear-gradient(145deg, #0d2238, #0a1d30);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--spacing-lg);
  margin-top: var(--spacing-xl);
}

.about-section h4 {
  margin: 0 0 var(--spacing-sm);
}

.about-section p {
  color: var(--muted);
  line-height: 1.6;
  margin: var(--spacing-sm) 0;
}

.app-version {
  font-size: 11px;
  color: var(--muted);
  margin-top: var(--spacing-md);
}