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

:root {
  --font-sans: 'Geist', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', Menlo, Monaco, monospace;
  
  --bg-page: #ffffff;
  --bg-subtle: #f8fafc;
  --bg-muted: #f1f5f9;
  --bg-panel: #ffffff;
  
  --ink-primary: #0f172a;
  --ink-secondary: #475569;
  --ink-muted: #64748b;
  --ink-inverse: #ffffff;
  
  --border-subtle: #f1f5f9;
  --border-crisp: #e2e8f0;
  --border-strong: #cbd5e1;
  
  --brand-green: #487823;
  --brand-green-hover: #3b631c;
  --brand-green-tint: #f3f8ee;
  --brand-green-border: #c8e0b4;
  
  --danger: #dc2626;
  --danger-hover: #b91c1c;
  --danger-tint: #fef2f2;
  --danger-border: #fecaca;
  
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.05);
  --shadow-md: 0 4px 12px rgba(15, 23, 42, 0.06);
  --shadow-lg: 0 12px 28px rgba(15, 23, 42, 0.08);
  
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-full: 9999px;
  
  --ease-spring: cubic-bezier(0.16, 1, 0.3, 1);
  --dur-fast: 150ms;
}

*, *::before, *::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--ink-primary);
  background-color: var(--bg-page);
  line-height: 1.55;
  font-size: 15px;
}

::selection {
  background-color: #d8ecc5;
  color: #1a3308;
}

::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}
::-webkit-scrollbar-track {
  background: var(--bg-subtle);
}
::-webkit-scrollbar-thumb {
  background: var(--border-strong);
  border-radius: var(--radius-full);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--ink-muted);
}

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

button, select, input {
  font: inherit;
  color: inherit;
}

button {
  cursor: pointer;
  background: transparent;
  border: 0;
}

:focus-visible {
  outline: 2px solid var(--brand-green);
  outline-offset: 2px;
}

.wrap {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.hidden {
  display: none !important;
}

/* 4-State Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 9px 18px;
  font-weight: 600;
  font-size: 14px;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  transition: all var(--dur-fast) var(--ease-spring);
  user-select: none;
  white-space: nowrap;
}

.btn:active {
  transform: scale(0.98);
}

.btn.green {
  background-color: var(--brand-green);
  color: var(--ink-inverse);
  border-color: var(--brand-green);
}
.btn.green:hover {
  background-color: var(--brand-green-hover);
  border-color: var(--brand-green-hover);
  box-shadow: 0 4px 12px rgba(72, 120, 35, 0.22);
}

.btn.outline {
  background-color: #ffffff;
  color: var(--ink-primary);
  border-color: var(--border-crisp);
}
.btn.outline:hover {
  background-color: var(--bg-subtle);
  border-color: var(--border-strong);
}

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

.btn.small {
  padding: 6px 12px;
  font-size: 13px;
  border-radius: var(--radius-sm);
}

.btn.big {
  padding: 13px 26px;
  font-size: 15px;
  font-weight: 700;
  border-radius: var(--radius-md);
}

/* Nav Bar */
.nav {
  height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 max(24px, calc((100vw - 1200px) / 2));
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-crisp);
}

.logo img {
  display: block;
  height: 38px;
  width: auto;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  font-weight: 500;
  font-size: 14px;
  color: var(--ink-secondary);
}

.nav-links a:hover {
  color: var(--ink-primary);
}

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

.menu-toggle {
  display: none;
  padding: 6px;
  color: var(--ink-primary);
}

/* Local Notice */
.local-notice {
  background: var(--brand-green-tint);
  border-bottom: 1px solid var(--brand-green-border);
  color: var(--brand-green-hover);
  text-align: center;
  font-size: 13px;
  font-weight: 600;
  padding: 8px 16px;
  letter-spacing: -0.01em;
}

/* Hero */
.hero {
  position: relative;
  background: #eaf3fa url('/assets/hero.jpg') center right / cover no-repeat;
  min-height: 480px;
  display: flex;
  align-items: center;
  border-bottom: 1px solid var(--border-crisp);
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, #ffffff 0%, rgba(255, 255, 255, 0.92) 50%, rgba(255, 255, 255, 0.2) 100%);
}

.hero-content {
  position: relative;
  max-width: 600px;
  padding: 64px 0;
  margin-left: 200px;
}

.hero h1 {
  font-size: clamp(34px, 4.5vw, 54px);
  font-weight: 800;
  line-height: 1.12;
  letter-spacing: -0.035em;
  margin: 0 0 16px;
  color: var(--ink-primary);
}

.hero p {
  font-size: 18px;
  color: var(--ink-secondary);
  line-height: 1.5;
  margin: 0 0 32px;
}

.hero-cta {
  display: flex;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
}

.video-link {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  font-size: 14px;
  color: var(--ink-secondary);
}

.video-link:hover {
  color: var(--ink-primary);
}

.video-link .play-icon {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-full);
  background: var(--brand-green-tint);
  border: 1px solid var(--brand-green-border);
  color: var(--brand-green);
  display: grid;
  place-items: center;
}

/* Stats Section */
.stats {
  padding: 64px 0 56px;
  text-align: center;
}

.stats h2, .courses h2, .catalog h2, .practice h2, .dashboard h2, .lessons h2, .arena h2 {
  font-size: clamp(26px, 3vw, 36px);
  font-weight: 800;
  letter-spacing: -0.03em;
  margin: 0 0 12px;
  color: var(--ink-primary);
}

.stat-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-top: 36px;
}

.stat-grid article {
  padding: 24px 16px;
  background: var(--bg-subtle);
  border: 1px solid var(--border-crisp);
  border-radius: var(--radius-md);
  text-align: center;
}

.stat-grid strong {
  display: block;
  font-size: 32px;
  font-weight: 800;
  color: var(--brand-green);
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
}

.stat-grid span {
  font-size: 14px;
  color: var(--ink-secondary);
  font-weight: 500;
}

/* Dashboard Section */
.dashboard {
  padding: 64px 0;
  background: var(--bg-subtle);
  border-top: 1px solid var(--border-crisp);
  border-bottom: 1px solid var(--border-crisp);
}

.section-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 20px;
  margin-bottom: 24px;
}

.section-head h2 {
  margin: 0;
}

.profile-toolbar {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.profile-toolbar label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  font-weight: 600;
  color: var(--ink-secondary);
}

.profile-toolbar select, .catalog-filters select, .catalog-filters input, .filters select, .lesson-filters select, .lesson-filters input, .arena-controls select {
  padding: 8px 12px;
  border: 1px solid var(--border-crisp);
  border-radius: var(--radius-sm);
  background: #ffffff;
  color: var(--ink-primary);
  font-size: 14px;
  transition: border-color var(--dur-fast);
}

.profile-toolbar select:focus, .catalog-filters select:focus, .catalog-filters input:focus, .filters select:focus, .lesson-filters select:focus, .lesson-filters input:focus, .arena-controls select:focus {
  border-color: var(--brand-green);
}

#data-status {
  min-height: 20px;
  font-size: 13px;
  font-weight: 600;
  color: var(--brand-green);
  margin: 0 0 16px;
}

.dashboard-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
  margin-bottom: 24px;
}

.dashboard-stats article {
  background: #ffffff;
  border: 1px solid var(--border-crisp);
  border-radius: var(--radius-md);
  padding: 20px;
}

.dashboard-stats strong {
  display: block;
  font-size: 28px;
  font-weight: 800;
  color: var(--brand-green);
  font-variant-numeric: tabular-nums;
  font-family: var(--font-mono);
  letter-spacing: -0.02em;
}

.dashboard-stats span {
  font-size: 13px;
  color: var(--ink-secondary);
  font-weight: 500;
}

.dashboard-columns {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 20px;
}

.panel {
  background: #ffffff;
  border: 1px solid var(--border-crisp);
  border-radius: var(--radius-md);
  padding: 22px;
  min-height: 240px;
}

.panel h3 {
  font-size: 16px;
  font-weight: 700;
  margin: 0 0 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-subtle);
  letter-spacing: -0.01em;
}

/* Subject Mastery Progress Bars */
.mastery-grid {
  display: grid;
  gap: 14px;
}

.mastery-item {
  display: grid;
  gap: 6px;
}

.mastery-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 13px;
}

.mastery-name {
  font-weight: 600;
  color: var(--ink-primary);
}

.mastery-meta {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  color: var(--ink-muted);
  font-variant-numeric: tabular-nums;
}

.mastery-track {
  height: 6px;
  background: var(--bg-muted);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.mastery-fill {
  height: 100%;
  background: var(--brand-green);
  border-radius: var(--radius-full);
  transition: width 0.3s var(--ease-spring);
}

.dashboard-link {
  display: block;
  width: 100%;
  border: 0;
  border-bottom: 1px solid var(--border-subtle);
  background: transparent;
  text-align: left;
  padding: 10px 0;
  font-size: 14px;
  font-weight: 600;
  transition: color var(--dur-fast);
}

.dashboard-link:hover {
  color: var(--brand-green);
}

.dashboard-link small {
  display: block;
  font-size: 12px;
  font-weight: 400;
  color: var(--ink-muted);
  margin-top: 2px;
}

.activity-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 9px 0;
  border-bottom: 1px solid var(--border-subtle);
  font-size: 13px;
}

.activity-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 20px;
  height: 20px;
  border-radius: 4px;
  font-size: 11px;
  font-weight: 700;
  margin-right: 8px;
}

.activity-badge.pass {
  background: var(--brand-green-tint);
  color: var(--brand-green);
  border: 1px solid var(--brand-green-border);
}

.activity-badge.fail {
  background: var(--danger-tint);
  color: var(--danger);
  border: 1px solid var(--danger-border);
}

.empty-state {
  color: var(--ink-muted);
  font-size: 13px;
  padding: 20px 0;
  text-align: center;
}

/* ARENA CHALLENGE */
.arena {
  padding: 64px 0;
}

.arena-card {
  background: #ffffff;
  border: 1px solid var(--border-crisp);
  border-radius: var(--radius-lg);
  padding: 36px;
  box-shadow: var(--shadow-sm);
}

.arena-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 24px;
  flex-wrap: wrap;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--border-crisp);
}

.arena-header h2 {
  margin: 0 0 8px;
}

.arena-header p {
  margin: 0;
  color: var(--ink-secondary);
  font-size: 15px;
  max-width: 500px;
}

.arena-telemetry {
  display: flex;
  gap: 12px;
}

.telemetry-box {
  background: var(--bg-subtle);
  border: 1px solid var(--border-crisp);
  border-radius: var(--radius-sm);
  padding: 10px 18px;
  text-align: center;
  min-width: 90px;
}

.tele-label {
  display: block;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--ink-muted);
  text-transform: uppercase;
  margin-bottom: 4px;
}

.tele-value {
  display: block;
  font-family: var(--font-mono);
  font-size: 24px;
  font-weight: 700;
  color: var(--ink-primary);
  font-variant-numeric: tabular-nums;
  line-height: 1;
}

#arena-timer {
  color: #c2410c;
}

#arena-streak {
  color: var(--brand-green);
}

.arena-controls {
  display: flex;
  align-items: flex-end;
  gap: 16px;
  margin-top: 32px;
  flex-wrap: wrap;
}

.arena-controls label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 13px;
  font-weight: 600;
  color: var(--ink-secondary);
}

.arena-controls select {
  min-width: 180px;
  padding: 11px 14px;
  border-radius: var(--radius-sm);
}

.arena-progress-bar {
  height: 6px;
  background: var(--bg-muted);
  border-radius: var(--radius-full);
  margin: 28px 0;
  overflow: hidden;
}

.arena-progress-fill {
  height: 100%;
  width: 0%;
  background: var(--brand-green);
  transition: width 0.25s var(--ease-spring);
}

.arena-question-box {
  margin-top: 24px;
}

.arena-question-box h3 {
  font-size: 20px;
  font-weight: 700;
  line-height: 1.4;
  margin: 0 0 24px;
}

.arena-choices {
  display: grid;
  gap: 10px;
}

.arena-choice-btn {
  display: flex;
  align-items: center;
  width: 100%;
  text-align: left;
  background: #ffffff;
  border: 1px solid var(--border-crisp);
  border-radius: var(--radius-sm);
  padding: 14px 18px;
  font-size: 15px;
  font-weight: 500;
  transition: all var(--dur-fast);
}

.arena-choice-btn:hover {
  border-color: var(--brand-green);
  background: var(--brand-green-tint);
}

.arena-choice-btn.correct {
  border-color: var(--brand-green);
  background: var(--brand-green-tint);
  color: var(--brand-green-hover);
  font-weight: 600;
}

.arena-choice-btn.wrong {
  border-color: var(--danger);
  background: var(--danger-tint);
  color: var(--danger-hover);
}

.arena-choice-prefix {
  font-family: var(--font-mono);
  font-weight: 700;
  margin-right: 14px;
  color: var(--ink-muted);
}

.arena-result {
  text-align: center;
  padding: 36px 0;
}

.arena-result h3 {
  font-size: 26px;
  font-weight: 800;
  margin: 0 0 24px;
  letter-spacing: -0.02em;
}

.arena-result-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  max-width: 640px;
  margin: 0 auto 32px;
}

.arena-result-stat {
  background: var(--bg-subtle);
  border: 1px solid var(--border-crisp);
  border-radius: var(--radius-sm);
  padding: 18px 12px;
}

.arena-result-stat strong {
  display: block;
  font-family: var(--font-mono);
  font-size: 26px;
  font-weight: 800;
  color: var(--brand-green);
  font-variant-numeric: tabular-nums;
}

.arena-result-stat span {
  font-size: 12px;
  font-weight: 600;
  color: var(--ink-muted);
}

/* LESSONS SECTION */
.lessons {
  padding: 64px 0;
  background: var(--bg-subtle);
  border-top: 1px solid var(--border-crisp);
  border-bottom: 1px solid var(--border-crisp);
}

.section-intro {
  margin: 0 0 28px;
  color: var(--ink-secondary);
  font-size: 15px;
}

.lesson-filters {
  display: flex;
  gap: 16px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.lesson-filters label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 13px;
  font-weight: 600;
  color: var(--ink-secondary);
}

.lesson-filters .search-label {
  flex: 1;
  min-width: 240px;
}

.lesson-layout {
  display: grid;
  grid-template-columns: 1fr 1.6fr;
  gap: 24px;
}

.lesson-list {
  display: grid;
  gap: 10px;
  max-height: 560px;
  overflow-y: auto;
  padding-right: 6px;
}

.lesson-item {
  display: block;
  width: 100%;
  text-align: left;
  border: 1px solid var(--border-crisp);
  background: #ffffff;
  border-radius: var(--radius-md);
  padding: 16px 18px;
  transition: all var(--dur-fast);
}

.lesson-item:hover {
  border-color: var(--border-strong);
  background: var(--bg-subtle);
}

.lesson-item.active {
  border-color: var(--brand-green);
  background: var(--brand-green-tint);
}

.lesson-item strong {
  display: block;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink-primary);
  margin-bottom: 4px;
}

.lesson-item span {
  display: block;
  font-size: 12px;
  font-weight: 600;
  color: var(--brand-green);
  margin-bottom: 6px;
}

.lesson-item small {
  display: block;
  font-size: 13px;
  color: var(--ink-muted);
  line-height: 1.4;
}

.lesson-view {
  background: #ffffff;
  border: 1px solid var(--border-crisp);
  border-radius: var(--radius-md);
  padding: 32px;
  box-shadow: var(--shadow-sm);
  min-height: 400px;
}

.lesson-view h3 {
  font-size: 24px;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin: 12px 0 20px;
}

.lesson-view p {
  font-size: 15px;
  line-height: 1.7;
  color: var(--ink-secondary);
  margin: 0 0 16px;
}

.lesson-tag {
  display: inline-block;
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--brand-green);
  background: var(--brand-green-tint);
  border: 1px solid var(--brand-green-border);
  padding: 3px 8px;
  border-radius: 4px;
}

/* Courses Grid */
.courses {
  padding: 64px 0;
  text-align: center;
}

.course-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-top: 32px;
}

.course-card {
  border-radius: var(--radius-md);
  border: 1px solid var(--border-crisp);
  padding: 24px 20px;
  text-align: left;
  display: flex;
  flex-direction: column;
  transition: transform var(--dur-fast), box-shadow var(--dur-fast);
  cursor: pointer;
  background: #ffffff;
}

.course-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: var(--border-strong);
}

.course-card img {
  width: 72px;
  height: 72px;
  align-self: center;
  object-fit: contain;
  margin-bottom: 12px;
}

.course-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin: 8px 0 4px;
  letter-spacing: -0.01em;
}

.course-card p {
  font-size: 13px;
  color: var(--ink-secondary);
  margin: 0 0 16px;
}

.course-card b {
  margin-top: auto;
  font-size: 13px;
  font-weight: 700;
  color: var(--brand-green);
}

/* Catalog Section */
.catalog {
  padding: 64px 0;
}

.catalog-filters {
  display: flex;
  gap: 14px;
  margin: 28px 0;
  flex-wrap: wrap;
}

.catalog-filters label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 13px;
  font-weight: 600;
  color: var(--ink-secondary);
  flex: 1;
  min-width: 160px;
}

.category-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.category-card {
  position: relative;
  background: #ffffff;
  border: 1px solid var(--border-crisp);
  border-radius: var(--radius-md);
  padding: 22px;
  transition: border-color var(--dur-fast);
}

.category-card:hover {
  border-color: var(--border-strong);
}

.category-card span {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--brand-green);
  text-transform: uppercase;
}

.category-card h3 {
  font-size: 16px;
  font-weight: 700;
  margin: 8px 0;
  padding-right: 28px;
  letter-spacing: -0.01em;
}

.category-card p {
  font-size: 13px;
  color: var(--ink-muted);
  margin: 0;
}

.bookmark {
  position: absolute;
  right: 14px;
  top: 14px;
  color: var(--ink-muted);
  padding: 4px;
  display: grid;
  place-items: center;
  border-radius: 4px;
  transition: color var(--dur-fast);
}

.bookmark:hover {
  color: var(--brand-green);
}

.bookmark.active {
  color: var(--brand-green);
}

.category-open {
  border: 0;
  background: transparent;
  color: var(--brand-green);
  font-weight: 600;
  font-size: 13px;
  padding: 10px 0 0;
  text-align: left;
}

.category-open:hover {
  text-decoration: underline;
}

.skills-panel:not(:empty) {
  margin-top: 28px;
  background: var(--bg-subtle);
  border: 1px solid var(--border-crisp);
  border-radius: var(--radius-md);
  padding: 24px;
}

.skills-panel h3 {
  font-size: 18px;
  font-weight: 700;
  margin: 0 0 16px;
}

.skill-list {
  display: grid;
  gap: 8px;
}

.skill-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 16px;
  background: #ffffff;
  border: 1px solid var(--border-crisp);
  border-radius: var(--radius-sm);
}

.skill-row strong {
  display: block;
  font-size: 14px;
  font-weight: 600;
}

.skill-row small {
  display: block;
  font-size: 12px;
  color: var(--ink-muted);
  margin-top: 2px;
}

.skill-row a {
  font-size: 13px;
  font-weight: 600;
  color: var(--brand-green);
  white-space: nowrap;
}

.source-note {
  font-size: 12px;
  color: var(--ink-muted);
  margin-top: 24px;
}

/* PRACTICE & QUIZ */
.practice {
  padding: 64px 0;
  background: var(--bg-subtle);
  border-top: 1px solid var(--border-crisp);
  border-bottom: 1px solid var(--border-crisp);
}

.practice-layout {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 48px;
  align-items: start;
}

.filters {
  display: flex;
  gap: 14px;
  margin: 24px 0;
}

.filters label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 13px;
  font-weight: 600;
  color: var(--ink-secondary);
  flex: 1;
}

.progress {
  margin-top: 20px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 600;
  color: var(--brand-green);
}

.quiz-card {
  background: #ffffff;
  border: 1px solid var(--border-crisp);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-sm);
  min-height: 360px;
}

.quiz-empty {
  text-align: center;
  padding: 48px 16px;
}

.quiz-empty h3 {
  font-size: 20px;
  font-weight: 700;
  margin: 12px 0 8px;
}

.quiz-empty p {
  font-size: 14px;
  color: var(--ink-muted);
  margin: 0;
}

.quiz-card .small {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  color: var(--ink-muted);
  letter-spacing: 0.06em;
}

.quiz-card h3 {
  font-size: 18px;
  font-weight: 700;
  line-height: 1.45;
  margin: 12px 0 20px;
}

.choice {
  display: block;
  width: 100%;
  text-align: left;
  background: #ffffff;
  border: 1px solid var(--border-crisp);
  border-radius: var(--radius-sm);
  padding: 12px 16px;
  margin: 8px 0;
  font-size: 14px;
  font-weight: 500;
  color: var(--ink-primary);
  transition: all var(--dur-fast);
}

.choice:hover {
  border-color: var(--brand-green);
  background: var(--brand-green-tint);
}

.choice.correct {
  border-color: var(--brand-green);
  background: var(--brand-green-tint);
  color: var(--brand-green-hover);
  font-weight: 600;
}

.choice.wrong {
  border-color: var(--danger);
  background: var(--danger-tint);
  color: var(--danger);
}

.feedback {
  font-size: 14px;
  font-weight: 600;
  margin: 16px 0;
}

.question-source {
  font-size: 12px;
  color: var(--ink-muted);
  margin-top: 20px;
  padding-top: 12px;
  border-top: 1px solid var(--border-subtle);
}

.question-source a {
  color: var(--brand-green);
  text-decoration: underline;
}

/* Footer */
footer {
  background: #0f172a;
  color: #94a3b8;
  padding: 64px 0 48px;
  font-size: 14px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1.2fr 1.8fr;
  gap: 48px;
}

footer img {
  height: 36px;
  width: auto;
  filter: brightness(0) invert(1);
  margin-bottom: 14px;
}

footer strong {
  display: block;
  color: #ffffff;
  font-size: 15px;
  font-weight: 700;
  margin-bottom: 16px;
}

footer a {
  display: block;
  color: #94a3b8;
  margin: 8px 0;
  transition: color var(--dur-fast);
}

footer a:hover {
  color: #ffffff;
}

.legal-note {
  font-size: 12px;
  color: #64748b;
  margin-top: 14px;
  line-height: 1.5;
}

/* Profile Dialog */
#profile-dialog {
  border: 1px solid var(--border-crisp);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: 28px;
  width: min(420px, calc(100vw - 32px));
  background: #ffffff;
}

#profile-dialog::backdrop {
  background: rgba(15, 23, 42, 0.45);
  backdrop-filter: blur(4px);
}

#profile-dialog h2 {
  font-size: 20px;
  font-weight: 700;
  margin: 0 0 16px;
}

#profile-dialog label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin: 14px 0;
  font-size: 13px;
  font-weight: 600;
}

#profile-dialog input, #profile-dialog select {
  padding: 10px 14px;
  border: 1px solid var(--border-crisp);
  border-radius: var(--radius-sm);
}

.dialog-actions {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
  margin-top: 24px;
}

#profile-error {
  color: var(--danger);
  font-size: 13px;
  margin: 8px 0 0;
}

/* RESPONSIVE DESIGN */
@media (max-width: 950px) {
  .dashboard-columns {
    grid-template-columns: 1fr;
  }
  .course-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .stat-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .dashboard-stats {
    grid-template-columns: repeat(2, 1fr);
  }
  .category-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .lesson-layout {
    grid-template-columns: 1fr;
  }
  .practice-layout {
    grid-template-columns: 1fr;
    gap: 32px;
  }
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }
  .hero-content {
    margin-left: 48px;
  }
}

@media (max-width: 650px) {
  .menu-toggle {
    display: block;
  }
  .nav-links {
    display: none;
    position: absolute;
    top: 72px;
    left: 0;
    right: 0;
    background: #ffffff;
    padding: 20px 24px;
    border-bottom: 1px solid var(--border-crisp);
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
  }
  .nav-links.open {
    display: flex;
  }
  .nav-actions {
    display: none;
  }
  .hero-content {
    padding: 48px 0;
    margin-left: 20px;
  }
  .category-grid {
    grid-template-columns: 1fr;
  }
  .stat-grid, .dashboard-stats {
    grid-template-columns: 1fr;
  }
  .arena-card {
    padding: 20px;
  }
  .arena-result-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}