:root {
  --bg: #0b0e17;
  --bg2: #111827;
  --bg3: #1a2236;
  --card: #151d2e;
  --card-hover: #1c2640;
  --ink: #e2e8f0;
  --muted: #94a3b8;
  --accent: #4a7aff;
  --accent2: #22d3ee;
  --accent3: #a78bfa;
  --success: #34d399;
  --warning: #fbbf24;
  --danger: #f87171;
  --border: #1e293b;
  --border-light: #334155;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--ink);
  line-height: 1.7;
  font-size: 15px;
  min-height: 100vh;
}

/* Scrollbar */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--bg2); }
::-webkit-scrollbar-thumb { background: var(--border-light); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--accent); }

/* Layout */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 56px;
  background: rgba(11,14,23,0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.5rem;
  z-index: 1000;
}

.navbar-brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--ink);
  text-decoration: none;
}

.navbar-brand .logo-icon {
  width: 32px; height: 32px;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.navbar-right {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.nav-btn {
  background: var(--bg3);
  border: 1px solid var(--border-light);
  color: var(--ink);
  padding: 0.4rem 0.9rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.85rem;
  transition: all 0.2s;
}

.nav-btn:hover { background: var(--card-hover); border-color: var(--accent); }

.nav-btn.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.nav-btn.primary:hover { background: #3d6be0; }

.user-info {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.85rem;
  color: var(--muted);
  white-space: nowrap;
}
.user-name {
  max-width: 80px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.user-avatar {
  width: 28px; height: 28px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent3), var(--accent));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  color: #fff;
}

/* Main */
.main-content {
  padding-top: 56px;
  min-height: 100vh;
}

/* Hero */
.hero {
  padding: 3rem 1.5rem 2rem;
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
}

.hero h1 {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  font-weight: 800;
  margin-bottom: 0.75rem;
  background: linear-gradient(135deg, var(--ink), var(--accent2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero p {
  color: var(--muted);
  font-size: 1rem;
  max-width: 520px;
  margin: 0 auto 1.5rem;
}

.progress-bar-wrap {
  max-width: 400px;
  margin: 0 auto;
}

.progress-bar-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--muted);
  margin-bottom: 0.4rem;
}

.progress-bar-track {
  height: 8px;
  background: var(--bg3);
  border-radius: 4px;
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  border-radius: 4px;
  transition: width 0.6s ease;
}

/* Modules */
.modules-container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1rem 3rem;
}

.module {
  margin-bottom: 1rem;
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  background: var(--bg2);
}

.module-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.25rem;
  cursor: pointer;
  background: var(--card);
  transition: background 0.2s;
}

.module-header:hover { background: var(--card-hover); }

.module-title {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.module-icon {
  width: 36px; height: 36px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
}

.module-name {
  font-size: 1rem;
  font-weight: 600;
}

.module-count {
  font-size: 0.75rem;
  color: var(--muted);
  margin-left: 0.5rem;
}

.module-toggle {
  font-size: 0.8rem;
  color: var(--muted);
  transition: transform 0.3s;
}

.module.open .module-toggle { transform: rotate(180deg); }

.module-body {
  display: none;
  padding: 1rem;
}

.module.open .module-body { display: block; }

/* Game Cards */
.game-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 0.75rem;
}

.game-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1rem;
  cursor: pointer;
  transition: all 0.2s;
  position: relative;
  overflow: hidden;
}

.game-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 4px 20px rgba(74,122,255,0.1);
}

.game-card.completed {
  border-color: var(--success);
}

.game-card.completed::after {
  content: '';
  position: absolute;
  top: 8px; right: 8px;
  width: 8px; height: 8px;
  background: var(--success);
  border-radius: 50%;
}

.game-card.played::after {
  content: '';
  position: absolute;
  top: 8px; right: 8px;
  width: 8px; height: 8px;
  background: var(--warning);
  border-radius: 50%;
}

.game-number {
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 0.3rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}
.game-number::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  flex-shrink: 0;
}

.game-title {
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 0.4rem;
  line-height: 1.4;
}

.game-desc {
  font-size: 0.78rem;
  color: var(--muted);
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.game-status {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.7rem;
  margin-top: 0.5rem;
  padding: 0.15rem 0.5rem;
  border-radius: 1rem;
  background: var(--bg3);
  color: var(--muted);
}

.game-status.completed { background: rgba(52,211,153,0.1); color: var(--success); }
.game-status.played { background: rgba(251,191,36,0.1); color: var(--warning); }

/* Modal */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.7);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 2000;
  padding: 1rem;
}

.modal-overlay.active { display: flex; }

.modal {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 16px;
  width: 100%;
  max-width: 420px;
  max-height: 90vh;
  overflow-y: auto;
  padding: 1.5rem;
}

.modal h2 {
  font-size: 1.2rem;
  margin-bottom: 1rem;
}

.modal-close {
  position: absolute;
  top: 1rem; right: 1rem;
  background: none;
  border: none;
  color: var(--muted);
  font-size: 1.2rem;
  cursor: pointer;
}

.form-group { margin-bottom: 1rem; }
.form-group label {
  display: block;
  font-size: 0.8rem;
  color: var(--muted);
  margin-bottom: 0.3rem;
}
.form-group input {
  width: 100%;
  padding: 0.6rem 0.8rem;
  background: var(--bg3);
  border: 1px solid var(--border-light);
  border-radius: 8px;
  color: var(--ink);
  font-size: 0.9rem;
}
.form-group input:focus {
  outline: none;
  border-color: var(--accent);
}

.btn {
  width: 100%;
  padding: 0.7rem;
  background: var(--accent);
  border: none;
  border-radius: 8px;
  color: #fff;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s;
}
.btn:hover { background: #3d6be0; }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

.form-footer {
  text-align: center;
  margin-top: 1rem;
  font-size: 0.8rem;
  color: var(--muted);
}
.form-footer a {
  color: var(--accent);
  cursor: pointer;
}

.error-msg {
  color: var(--danger);
  font-size: 0.8rem;
  margin-top: 0.5rem;
  min-height: 1.2rem;
}

/* Game Page Shared */
.game-page {
  max-width: 800px;
  margin: 0 auto;
  padding: 1.5rem;
  padding-top: calc(56px + 1.5rem);
}

.game-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.game-nav h1 {
  font-size: 1.3rem;
  font-weight: 700;
}

.game-nav-btns {
  display: flex;
  gap: 0.5rem;
}

.game-nav-btns .nav-btn {
  padding: 0.35rem 0.7rem;
  font-size: 0.8rem;
}

.game-instruction {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem;
  margin-bottom: 1.5rem;
}

.game-instruction h3 {
  font-size: 0.95rem;
  margin-bottom: 0.5rem;
  color: var(--accent2);
}

.game-instruction p {
  font-size: 0.85rem;
  color: var(--muted);
  line-height: 1.7;
}

.game-area {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  min-height: 300px;
}

.feedback-box {
  margin-top: 1.5rem;
  padding: 1rem 1.25rem;
  border-radius: 10px;
  font-size: 0.9rem;
  line-height: 1.7;
  display: none;
}

.feedback-box.show { display: block; }
.feedback-box.correct { background: rgba(52,211,153,0.08); border: 1px solid var(--success); }
.feedback-box.wrong { background: rgba(248,113,113,0.08); border: 1px solid var(--danger); }
.feedback-box.info { background: rgba(74,122,255,0.08); border: 1px solid var(--accent); }

/* Catalog Modal */
.catalog-modal .modal { max-width: 600px; }
.catalog-search {
  width: 100%;
  padding: 0.6rem 0.9rem;
  background: var(--bg3);
  border: 1px solid var(--border-light);
  border-radius: 8px;
  color: var(--ink);
  font-size: 0.9rem;
  margin-bottom: 1rem;
}
.catalog-search:focus { outline: none; border-color: var(--accent); }

.catalog-list {
  max-height: 50vh;
  overflow-y: auto;
}

.catalog-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.6rem 0.5rem;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.15s;
}
.catalog-item:hover { background: var(--bg3); }
.catalog-item-num {
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--accent);
  min-width: 28px;
}
.catalog-item-title { font-size: 0.85rem; }
.catalog-item-status {
  margin-left: auto;
  font-size: 0.7rem;
  padding: 0.1rem 0.4rem;
  border-radius: 1rem;
}
.catalog-item-status.completed { background: rgba(52,211,153,0.1); color: var(--success); }
.catalog-item-status.played { background: rgba(251,191,36,0.1); color: var(--warning); }

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}
.fade-in { animation: fadeIn 0.4s ease; }

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}
.pulse { animation: pulse 2s infinite; }

/* Toast */
.toast-container {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 3000;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.toast {
  padding: 0.7rem 1rem;
  border-radius: 8px;
  font-size: 0.85rem;
  color: #fff;
  background: var(--bg2);
  border: 1px solid var(--border-light);
  animation: fadeIn 0.3s ease;
  max-width: 300px;
}
.toast.success { border-color: var(--success); color: var(--success); }
.toast.error { border-color: var(--danger); color: var(--danger); }

/* Page Loader */
.page-loader {
  position: fixed;
  inset: 0;
  background: var(--bg);
  z-index: 9999;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 1rem;
  transition: opacity 0.4s ease;
}
.page-loader.hidden { opacity: 0; pointer-events: none; }
.page-loader .loader-ring {
  width: 40px; height: 40px;
  border: 3px solid var(--border-light);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }
.page-loader .loader-text {
  font-size: 0.85rem;
  color: var(--muted);
}

/* Achievement System */
.achievement-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.7rem;
  border-radius: 1rem;
  font-size: 0.78rem;
  font-weight: 600;
  background: var(--bg3);
  border: 1px solid var(--border-light);
  color: var(--muted);
}
.achievement-badge.unlocked {
  background: linear-gradient(135deg, rgba(74,122,255,0.15), rgba(34,211,238,0.1));
  border-color: var(--accent);
  color: var(--accent);
}

/* Knowledge Card */
.knowledge-card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem;
  margin-top: 1rem;
}
.knowledge-card h4 {
  font-size: 0.9rem;
  color: var(--accent2);
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}
.knowledge-card .card-actions {
  display: flex;
  gap: 0.5rem;
  margin-top: 0.75rem;
}
.card-btn {
  padding: 0.4rem 0.8rem;
  border-radius: 6px;
  border: 1px solid var(--border-light);
  background: var(--bg3);
  color: var(--ink);
  font-size: 0.8rem;
  cursor: pointer;
  transition: all 0.2s;
}
.card-btn:hover { border-color: var(--accent); }
.card-btn.saved { border-color: var(--success); color: var(--success); }

/* Difficulty Label */
.difficulty-tag {
  display: inline-block;
  font-size: 0.65rem;
  font-weight: 700;
  padding: 0.1rem 0.4rem;
  border-radius: 1rem;
  margin-left: 0.4rem;
  vertical-align: middle;
}
.difficulty-tag.beginner { background: rgba(52,211,153,0.12); color: var(--success); }
.difficulty-tag.intermediate { background: rgba(251,191,36,0.12); color: var(--warning); }
.difficulty-tag.advanced { background: rgba(248,113,113,0.12); color: var(--danger); }

/* Module Description */
.module-desc {
  font-size: 0.8rem;
  color: var(--muted);
  margin-top: 0.25rem;
  padding-left: 0.5rem;
  border-left: 2px solid var(--border-light);
}

/* Random Pick Button */
.random-pick-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.6rem 1.2rem;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  border: none;
  border-radius: 10px;
  color: #fff;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  margin-top: 0.5rem;
}
.random-pick-btn:hover { transform: translateY(-2px); box-shadow: 0 4px 20px rgba(74,122,255,0.3); }

/* Daily Challenge Banner */
.daily-banner {
  background: linear-gradient(135deg, rgba(74,122,255,0.08), rgba(167,139,250,0.08));
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem;
  margin: 1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
}
.daily-banner h3 { font-size: 1rem; color: var(--accent); }
.daily-banner p { font-size: 0.8rem; color: var(--muted); }

/* Learning Path */
.path-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1rem 1.25rem;
  margin: 0.5rem 0;
  cursor: pointer;
  transition: all 0.2s;
}
.path-card:hover { border-color: var(--accent); }
.path-card .path-title { font-weight: 600; font-size: 0.9rem; }
.path-card .path-meta { font-size: 0.75rem; color: var(--muted); margin-top: 0.2rem; }

/* Reference citation */
.ref-box {
  font-size: 0.75rem;
  color: var(--muted);
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
}
.ref-box strong { color: var(--accent2); }

/* Application section */
.app-section {
  background: linear-gradient(135deg, rgba(34,211,238,0.05), rgba(74,122,255,0.05));
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1rem 1.25rem;
  margin-top: 1rem;
}
.app-section h4 {
  font-size: 0.9rem;
  color: var(--accent2);
  margin-bottom: 0.5rem;
}
.app-section p { font-size: 0.85rem; color: var(--muted); line-height: 1.7; }

/* Responsive */
@media (max-width: 600px) {
  .game-grid { grid-template-columns: 1fr; }
  .hero { padding: 2rem 1rem 1.5rem; }
  .game-page { padding: 1rem; padding-top: calc(56px + 1rem); }
  .navbar { padding: 0 1rem; }
  .daily-banner { margin: 1rem; }
}