/* ─── AnimalsF-F Global Styles ─── */

:root {
  --bg-dark: #0f1117;
  --bg-card: #1a1d28;
  --bg-card-hover: #222636;
  --bg-input: #151821;
  --border: #2a2e3d;
  --border-light: #363b4e;
  --text: #e8e9ed;
  --text-dim: #8b8fa3;
  --text-muted: #5c6070;
  --accent: #6ee7b7;
  --accent-dim: #34d399;
  --accent-glow: rgba(110, 231, 183, 0.15);
  --hp-color: #ef4444;
  --hp-fill: #f87171;
  --atp-color: #06b6d4;
  --atp-fill: #22d3ee;
  --adapt-color: #a855f7;
  --adapt-fill: #c084fc;
  --score-color: #fbbf24;

  /* Rank colors */
  --rank-x: linear-gradient(135deg, #fff, #06b6d4, #a855f7, #ec4899);
  --rank-sss: linear-gradient(135deg, #f59e0b, #ef4444, #a855f7, #06b6d4);
  --rank-ss: linear-gradient(135deg, #f59e0b, #fbbf24);
  --rank-s: linear-gradient(135deg, #fbbf24, #f59e0b);
  --rank-a: linear-gradient(135deg, #a855f7, #7c3aed);
  --rank-b: linear-gradient(135deg, #3b82f6, #2563eb);
  --rank-c: linear-gradient(135deg, #22c55e, #16a34a);
  --rank-d: linear-gradient(135deg, #f59e0b, #d97706);
  --rank-e: linear-gradient(135deg, #f97316, #ea580c);
  --rank-f: linear-gradient(135deg, #ef4444, #dc2626);
  --rank-g: linear-gradient(135deg, #6b7280, #4b5563);

  --radius: 12px;
  --radius-sm: 8px;
  --transition: 0.2s ease;
}

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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg-dark);
  color: var(--text);
  min-height: 100dvh;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

#app {
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}

/* ─── Typography ─── */

h1 { font-size: 1.75rem; font-weight: 800; }
h2 { font-size: 1.5rem; font-weight: 700; }
h3 { font-size: 1.125rem; font-weight: 600; }

/* ─── Buttons ─── */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.9375rem;
  cursor: pointer;
  border: none;
  transition: all var(--transition);
  text-decoration: none;
  font-family: inherit;
}

.btn-primary {
  background: var(--accent);
  color: var(--bg-dark);
}
.btn-primary:hover {
  background: var(--accent-dim);
  transform: translateY(-1px);
}

.btn-ghost {
  background: transparent;
  color: var(--text-dim);
  border: 1px solid var(--border);
}
.btn-ghost:hover {
  color: var(--text);
  border-color: var(--border-light);
  background: var(--bg-card);
}

.btn-large {
  padding: 1rem 2rem;
  font-size: 1.125rem;
  border-radius: var(--radius);
}

.btn-small {
  padding: 0.4rem 0.8rem;
  font-size: 0.8125rem;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

/* ─── Page header ─── */

.page-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--border);
  background: var(--bg-card);
}

.page-header h1 {
  flex: 1;
  font-size: 1.25rem;
}

.back-btn {
  color: var(--text-dim);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.9375rem;
  padding: 0.4rem 0.6rem;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
}
.back-btn:hover {
  color: var(--text);
  background: var(--bg-card-hover);
}

.user-mini {
  color: var(--text-dim);
  font-size: 0.875rem;
}

/* ─── Landing page ─── */

.landing-page {
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
}

.landing-bg-pattern {
  position: fixed;
  inset: 0;
  background:
    radial-gradient(circle at 20% 20%, rgba(110, 231, 183, 0.05) 0%, transparent 50%),
    radial-gradient(circle at 80% 80%, rgba(168, 85, 247, 0.05) 0%, transparent 50%);
  pointer-events: none;
}

.landing-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.5rem;
  position: relative;
  z-index: 1;
}

.landing-logo {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.landing-logo h1 {
  font-size: 1.5rem;
  letter-spacing: -0.02em;
}

.landing-logo .accent {
  color: var(--accent);
}

.landing-logo .subtitle {
  font-size: 0.8125rem;
  color: var(--text-dim);
  font-weight: 400;
}

/* Logo organism animation */
.logo-organism {
  width: 48px;
  height: 48px;
  position: relative;
}

.cell-body {
  width: 36px;
  height: 36px;
  border-radius: 50% 45% 50% 45%;
  background: linear-gradient(135deg, var(--accent), var(--adapt-color));
  position: absolute;
  top: 6px;
  left: 6px;
  animation: cell-breathe 3s ease-in-out infinite;
}

.cell-body.large {
  width: 80px;
  height: 80px;
  top: 10px;
  left: 10px;
}

.cell-nucleus {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.3);
  position: absolute;
  top: 16px;
  left: 16px;
}

.cell-nucleus.large {
  width: 30px;
  height: 30px;
  top: 32px;
  left: 32px;
}

.cell-flagellum {
  width: 20px;
  height: 3px;
  background: var(--accent);
  position: absolute;
  top: 24px;
  right: 0;
  border-radius: 2px;
  animation: flagellum-wave 1.5s ease-in-out infinite;
  opacity: 0.6;
}

.cell-flagellum.large {
  width: 40px;
  height: 4px;
  top: 50px;
  right: -10px;
}

@keyframes cell-breathe {
  0%, 100% { transform: scale(1); border-radius: 50% 45% 50% 45%; }
  50% { transform: scale(1.05); border-radius: 45% 50% 45% 50%; }
}

@keyframes flagellum-wave {
  0%, 100% { transform: rotate(0deg) scaleX(1); }
  25% { transform: rotate(8deg) scaleX(0.9); }
  75% { transform: rotate(-8deg) scaleX(1.1); }
}

/* User badge */
.user-badge {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 0.8rem;
  background: var(--bg-card);
  border-radius: 999px;
  border: 1px solid var(--border);
}

.user-avatar {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  object-fit: cover;
}

.user-avatar-placeholder {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--accent-glow);
  color: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.8125rem;
}

.user-name {
  font-size: 0.875rem;
  font-weight: 500;
}

/* Landing content */
.landing-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 2rem 1.5rem;
  position: relative;
  z-index: 1;
}

.chapter-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 0.8125rem;
  color: var(--text-dim);
  margin-bottom: 1.5rem;
}

.landing-tagline {
  text-align: center;
  margin-bottom: 2.5rem;
  max-width: 500px;
}

.landing-tagline h2 {
  font-size: 2rem;
  margin-bottom: 0.5rem;
  background: linear-gradient(135deg, var(--text), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.landing-tagline p {
  color: var(--text-dim);
  font-size: 1rem;
}

/* Mode cards */
.mode-cards {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  width: 100%;
  max-width: 520px;
}

.mode-card {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1.25rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  text-decoration: none;
  color: var(--text);
  transition: all var(--transition);
}

.mode-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-light);
  transform: translateY(-2px);
}

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

.mode-info h3 {
  font-size: 1rem;
  margin-bottom: 0.2rem;
}

.mode-info p {
  font-size: 0.8125rem;
  color: var(--text-dim);
  line-height: 1.4;
}

.mode-arrow {
  margin-left: auto;
  font-size: 1.25rem;
  color: var(--text-muted);
}

.mode-study:hover { border-color: var(--accent); }
.mode-story:hover { border-color: var(--adapt-color); }
.mode-leaderboard:hover { border-color: var(--score-color); }

/* Login prompt */
.login-prompt {
  width: 100%;
  max-width: 400px;
}

.login-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  text-align: center;
}

.login-card h3 { margin-bottom: 0.5rem; }
.login-card p {
  color: var(--text-dim);
  font-size: 0.9375rem;
  margin-bottom: 1.5rem;
}

/* Footer */
.landing-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.5rem;
  border-top: 1px solid var(--border);
  position: relative;
  z-index: 1;
}

.back-link {
  color: var(--text-dim);
  text-decoration: none;
  font-size: 0.875rem;
}
.back-link:hover { color: var(--accent); }

.footer-text {
  color: var(--text-muted);
  font-size: 0.8125rem;
}

/* ─── Study page ─── */

.study-page {
  display: flex;
  flex-direction: column;
  min-height: 100dvh;
}

.study-container {
  display: flex;
  flex: 1;
  min-height: 0;
}

.study-sidebar {
  width: 280px;
  padding: 1.5rem;
  border-right: 1px solid var(--border);
  overflow-y: auto;
  flex-shrink: 0;
}

.study-sidebar h3 {
  margin-bottom: 0.75rem;
  color: var(--text-dim);
  font-size: 0.8125rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.topic-btn {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  width: 100%;
  padding: 0.6rem 0.75rem;
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  color: var(--text-dim);
  cursor: pointer;
  font-size: 0.875rem;
  text-align: left;
  font-family: inherit;
  transition: all var(--transition);
  margin-bottom: 0.25rem;
}

.topic-btn:hover { background: var(--bg-card); color: var(--text); }
.topic-btn.active {
  background: var(--accent-glow);
  color: var(--accent);
  border-color: var(--accent);
}

.topic-count {
  margin-left: auto;
  font-size: 0.75rem;
  background: var(--bg-input);
  padding: 0.1rem 0.4rem;
  border-radius: 4px;
}

.study-options {
  margin-top: 1.5rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
}

.option-toggle {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 0;
  cursor: pointer;
  font-size: 0.875rem;
  color: var(--text-dim);
}

.option-toggle input[type="checkbox"] {
  accent-color: var(--accent);
  width: 16px;
  height: 16px;
}

.btn-start-study {
  width: 100%;
  margin-top: 1.5rem;
}

/* Study main area */
.study-main {
  flex: 1;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  max-width: 720px;
  margin: 0 auto;
  width: 100%;
}

.study-progress {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.progress-bar {
  flex: 1;
  height: 6px;
  background: var(--bg-input);
  border-radius: 3px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 3px;
  transition: width 0.3s ease;
}

.progress-text {
  font-size: 0.8125rem;
  color: var(--text-dim);
  white-space: nowrap;
}

.study-nav {
  margin-top: auto;
  padding-top: 1rem;
  display: flex;
  justify-content: center;
}

/* Study summary */
.study-summary {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
}

.summary-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2.5rem;
  text-align: center;
  max-width: 400px;
  width: 100%;
}

.summary-card h2 { margin-bottom: 1.5rem; }

.summary-stats {
  display: flex;
  gap: 1.5rem;
  justify-content: center;
  margin-bottom: 2rem;
}

.stat-item {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.stat-value {
  font-size: 2rem;
  font-weight: 800;
  color: var(--accent);
}

.stat-label {
  font-size: 0.8125rem;
  color: var(--text-dim);
}

.summary-actions {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

/* ─── Question card ─── */

.question-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  animation: fadeIn 0.3s ease;
}

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

.question-type-badge {
  display: inline-block;
  padding: 0.2rem 0.6rem;
  background: var(--bg-input);
  border-radius: 4px;
  font-size: 0.75rem;
  color: var(--text-dim);
  margin-bottom: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.question-difficulty {
  display: inline-block;
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  font-size: 0.7rem;
  font-weight: 600;
  margin-left: 0.5rem;
  text-transform: uppercase;
}
.diff-easy { background: rgba(34, 197, 94, 0.15); color: #22c55e; }
.diff-medium { background: rgba(251, 191, 36, 0.15); color: #fbbf24; }
.diff-hard { background: rgba(239, 68, 68, 0.15); color: #ef4444; }

.question-text {
  font-size: 1.0625rem;
  font-weight: 500;
  margin-bottom: 1.25rem;
  line-height: 1.6;
}

/* Definition terms in questions */
.dfn {
  text-decoration: underline;
  text-decoration-style: dotted;
  text-underline-offset: 3px;
  cursor: help;
  color: var(--accent);
  transition: color var(--transition);
}
.dfn:hover {
  color: var(--accent-dim);
}

/* MC options */
.mc-options {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.mc-option {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.875rem 1rem;
  background: var(--bg-input);
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition);
  font-family: inherit;
  font-size: 0.9375rem;
  color: var(--text);
  text-align: left;
  width: 100%;
}

.mc-option:hover:not(:disabled) {
  border-color: var(--border-light);
  background: var(--bg-card-hover);
}

.mc-option .option-letter {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--bg-card);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.8125rem;
  color: var(--text-dim);
  flex-shrink: 0;
}

.mc-option.selected {
  border-color: var(--atp-color);
  background: rgba(6, 182, 212, 0.1);
}
.mc-option.correct {
  border-color: #22c55e;
  background: rgba(34, 197, 94, 0.1);
}
.mc-option.correct .option-letter {
  background: #22c55e;
  color: #fff;
}
.mc-option.wrong {
  border-color: #ef4444;
  background: rgba(239, 68, 68, 0.1);
}
.mc-option.wrong .option-letter {
  background: #ef4444;
  color: #fff;
}
.mc-option:disabled { cursor: default; }

/* Fill in blank */
.fill-blank-input {
  width: 100%;
  padding: 0.875rem 1rem;
  background: var(--bg-input);
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-family: inherit;
  font-size: 1rem;
  transition: border-color var(--transition);
}
.fill-blank-input:focus {
  outline: none;
  border-color: var(--accent);
}
.fill-blank-input::placeholder {
  color: var(--text-muted);
}

.fill-submit-row {
  display: flex;
  gap: 0.5rem;
  margin-top: 0.75rem;
}

/* Matching */
.matching-pairs {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.matching-pair {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.matching-left {
  flex: 1;
  padding: 0.75rem;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
}

.matching-select {
  flex: 1;
  padding: 0.75rem;
  background: var(--bg-input);
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-family: inherit;
  font-size: 0.875rem;
  cursor: pointer;
}
.matching-select:focus {
  border-color: var(--accent);
  outline: none;
}

/* Explanation */
.explanation-box {
  margin-top: 1rem;
  padding: 1rem;
  border-radius: var(--radius-sm);
  border-left: 3px solid;
  animation: fadeIn 0.3s ease;
}
.explanation-box.correct-exp {
  background: rgba(34, 197, 94, 0.08);
  border-color: #22c55e;
}
.explanation-box.wrong-exp {
  background: rgba(239, 68, 68, 0.08);
  border-color: #ef4444;
}
.explanation-box h4 {
  font-size: 0.875rem;
  margin-bottom: 0.5rem;
}
.explanation-box p {
  font-size: 0.875rem;
  color: var(--text-dim);
  line-height: 1.6;
}

.override-btn {
  margin-top: 0.75rem;
  padding: 0.5rem 1rem;
  background: rgba(251, 191, 36, 0.15);
  border: 1px solid rgba(251, 191, 36, 0.3);
  border-radius: var(--radius-sm);
  color: #fbbf24;
  cursor: pointer;
  font-family: inherit;
  font-size: 0.8125rem;
  font-weight: 500;
  transition: all var(--transition);
}
.override-btn:hover {
  background: rgba(251, 191, 36, 0.25);
}

.question-next-btn {
  margin-top: 1rem;
  width: 100%;
}

/* ─── Definition popup ─── */

.def-popup {
  position: fixed;
  z-index: 1000;
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  padding: 0.75rem 1rem;
  max-width: 300px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
  font-size: 0.875rem;
  color: var(--text-dim);
  line-height: 1.5;
  animation: fadeIn 0.15s ease;
}

.def-popup-close {
  position: absolute;
  top: 0.3rem;
  right: 0.5rem;
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 1.1rem;
  padding: 0.2rem;
}

.def-popup-content strong {
  color: var(--accent);
  display: block;
  margin-bottom: 0.25rem;
}

/* ─── Story page ─── */

.story-page {
  display: flex;
  flex-direction: column;
  min-height: 100dvh;
}

/* ─── Story hub ─── */

.story-hub {
  max-width: 600px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

.story-hero {
  text-align: center;
  margin-bottom: 2rem;
}

.hero-organism {
  width: 100px;
  height: 100px;
  margin: 0 auto 1rem;
  position: relative;
}

.story-hero h2 {
  margin-bottom: 0.5rem;
}
.story-hero p {
  color: var(--text-dim);
  font-size: 0.9375rem;
}

.story-actions {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-bottom: 2rem;
}

.active-run-card {
  background: var(--bg-card);
  border: 1px solid var(--accent);
  border-radius: var(--radius);
  padding: 1.25rem;
}

.active-run-card h3 { margin-bottom: 0.5rem; }

.run-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 1rem;
  font-size: 0.875rem;
  color: var(--text-dim);
}

.run-stats span {
  padding: 0.2rem 0.6rem;
  background: var(--bg-input);
  border-radius: 4px;
}

.run-actions {
  display: flex;
  gap: 0.5rem;
}

.user-stats-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  margin-top: 0.75rem;
}

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

.stat-box .stat-value {
  font-size: 1.5rem;
  font-weight: 800;
  display: block;
}

.stat-box .stat-label {
  font-size: 0.75rem;
}

/* Rank guide */
.rank-guide {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
}

.rank-guide h3 { margin-bottom: 1rem; }

.rank-tiers {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.rank-tier {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.4rem 0.8rem;
  border-radius: var(--radius-sm);
  font-size: 0.8125rem;
  border: 1px solid var(--border);
  background: var(--bg-input);
}

.rank-letter {
  font-weight: 800;
}

.rank-x .rank-letter { background: var(--rank-x); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.rank-sss .rank-letter { background: var(--rank-sss); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.rank-ss .rank-letter { color: #f59e0b; }
.rank-s .rank-letter { color: #fbbf24; }
.rank-a .rank-letter { color: #a855f7; }
.rank-b .rank-letter { color: #3b82f6; }
.rank-c .rank-letter { color: #22c55e; }
.rank-d .rank-letter { color: #f59e0b; }
.rank-e .rank-letter { color: #f97316; }
.rank-f .rank-letter { color: #ef4444; }
.rank-g .rank-letter { color: #6b7280; }

/* Rank badges */
.rank-badge {
  display: inline-block;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 800;
}

/* ─── Leaderboard ─── */

.leaderboard-page {
  display: flex;
  flex-direction: column;
  min-height: 100dvh;
}

.leaderboard-container {
  max-width: 700px;
  margin: 0 auto;
  padding: 1.5rem;
}

.empty-state {
  text-align: center;
  padding: 3rem 1.5rem;
}

.empty-icon { font-size: 3rem; margin-bottom: 1rem; }
.empty-state h3 { margin-bottom: 0.5rem; }
.empty-state p { color: var(--text-dim); margin-bottom: 1.5rem; }

.lb-table {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.lb-row {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.875rem 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  transition: all var(--transition);
}

.lb-row:hover { background: var(--bg-card-hover); }

.lb-top-1 { border-color: #fbbf24; }
.lb-top-2 { border-color: #94a3b8; }
.lb-top-3 { border-color: #cd7f32; }
.lb-self { border-color: var(--accent); background: var(--accent-glow); }

.lb-rank { font-size: 1.25rem; width: 40px; text-align: center; }
.lb-rank-num { color: var(--text-muted); font-weight: 600; }

.lb-user {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex: 1;
  min-width: 0;
}

.lb-avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  object-fit: cover;
}

.lb-avatar-placeholder {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--bg-input);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.8125rem;
  color: var(--text-dim);
  flex-shrink: 0;
}

.lb-name {
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.lb-score {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.lb-score-value { font-weight: 700; font-size: 1.0625rem; }

.lb-plays {
  font-size: 0.8125rem;
  color: var(--text-muted);
  white-space: nowrap;
}

.lb-plays-label {
  display: none;
}

/* ─── Results page ─── */

.results-page {
  min-height: 100dvh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
}

.results-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 3rem 2rem;
  text-align: center;
  max-width: 450px;
  width: 100%;
}

.rank-display {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 1.5rem;
  font-size: 2.5rem;
  font-weight: 900;
  animation: rankPulse 2s ease-in-out infinite;
}

@keyframes rankPulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.05); }
}

.rank-display.rank-x { background: var(--rank-x); color: #0f1117; }
.rank-display.rank-sss { background: var(--rank-sss); color: #0f1117; }
.rank-display.rank-ss { background: var(--rank-ss); color: #0f1117; }
.rank-display.rank-s { background: var(--rank-s); color: #0f1117; }
.rank-display.rank-a { background: var(--rank-a); color: #fff; }
.rank-display.rank-b { background: var(--rank-b); color: #fff; }
.rank-display.rank-c { background: var(--rank-c); color: #fff; }
.rank-display.rank-d { background: var(--rank-d); color: #0f1117; }
.rank-display.rank-e { background: var(--rank-e); color: #fff; }
.rank-display.rank-f { background: var(--rank-f); color: #fff; }
.rank-display.rank-g { background: var(--rank-g); color: #fff; }

.results-score {
  margin-bottom: 1.5rem;
}

.score-number {
  font-size: 3rem;
  font-weight: 900;
  color: var(--score-color);
  display: block;
}

.score-label {
  color: var(--text-dim);
  font-size: 0.875rem;
}

.results-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  margin-bottom: 2rem;
}

.result-stat {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.rs-value {
  font-size: 1.25rem;
  font-weight: 700;
}

.rs-label {
  font-size: 0.8125rem;
  color: var(--text-dim);
}

.results-actions {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

/* ─── Error page ─── */

.error-page {
  min-height: 100dvh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
}

.error-card {
  text-align: center;
  max-width: 400px;
}

.error-icon { font-size: 3rem; margin-bottom: 1rem; }
.error-card h1 { margin-bottom: 0.5rem; }
.error-card p { color: var(--text-dim); margin-bottom: 1.5rem; }

/* ─── Responsive ─── */

@media (max-width: 768px) {
  .study-container {
    flex-direction: column;
  }

  .study-sidebar {
    width: 100%;
    border-right: none;
    border-bottom: 1px solid var(--border);
    max-height: 50vh;
  }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .landing-tagline h2 {
    font-size: 1.5rem;
  }

  .lb-plays-label { display: inline; }
}

@media (max-width: 480px) {
  .summary-stats {
    flex-direction: column;
    gap: 0.75rem;
  }

  .results-stats {
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
  }

  .rank-tiers {
    gap: 0.3rem;
  }

  .rank-tier {
    font-size: 0.75rem;
    padding: 0.3rem 0.5rem;
  }
}