:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #111118;
  --bg-card: rgba(255, 255, 255, 0.04);
  --bg-card-hover: rgba(255, 255, 255, 0.08);
  --border: rgba(255, 255, 255, 0.1);
  --border-strong: rgba(255, 255, 255, 0.18);
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent-cyan: #22d3ee;
  --accent-cyan-dim: rgba(34, 211, 238, 0.15);
  --accent-amber: #fbbf24;
  --accent-amber-dim: rgba(251, 191, 36, 0.15);
  --accent-rose: #f472b6;
  --accent-violet: #a78bfa;
  --accent-emerald: #34d399;
  --radius: 1rem;
  --radius-lg: 1.5rem;
  --shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
  --font-sans: "Inter", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-display: Georgia, "Noto Serif SC", "Songti SC", serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  overflow-x: hidden;
}

::-webkit-scrollbar {
  width: 8px;
}

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

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

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

/* Background canvas */
#particle-canvas {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: 0.6;
}

/* Navigation */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 1rem 2rem;
  background: rgba(10, 10, 15, 0.7);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  transition: all 0.3s ease;
}

.nav-inner {
  max-width: 1400px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--text-primary);
  text-decoration: none;
}

.logo-mark {
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 50%;
  background: conic-gradient(from 0deg, var(--accent-cyan), var(--accent-amber), var(--accent-violet), var(--accent-cyan));
  display: grid;
  place-items: center;
  font-size: 0.875rem;
  color: var(--bg-primary);
}

.nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s;
  position: relative;
}

.nav-links a::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent-cyan);
  transition: width 0.3s;
}

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

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.audio-toggle {
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  display: grid;
  place-items: center;
  transition: all 0.2s;
}

.audio-toggle:hover {
  background: var(--accent-cyan-dim);
  color: var(--accent-cyan);
  border-color: var(--accent-cyan);
}

.lang-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  height: 2.5rem;
  padding: 0 0.9rem;
  border-radius: 1.25rem;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  font-family: var(--font-sans);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  transition: all 0.2s;
}

.lang-toggle:hover {
  background: var(--accent-amber-dim);
  color: var(--accent-amber);
  border-color: var(--accent-amber);
}

.lang-toggle svg {
  width: 1.1rem;
  height: 1.1rem;
  flex-shrink: 0;
}

@media (max-width: 560px) {
  .lang-toggle span {
    display: none;
  }
  .lang-toggle {
    padding: 0 0.7rem;
  }
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
}

/* Sections */
.section {
  position: relative;
  z-index: 1;
  padding: 6rem 2rem;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
}

/* Section heading */
.section-heading {
  margin-bottom: 3rem;
  max-width: 780px;
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 1rem;
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-cyan) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-subtitle {
  color: var(--text-secondary);
  font-size: 1.125rem;
  max-width: 65ch;
  margin-bottom: 3rem;
}

/* Hero */
.hero {
  min-height: 100dvh;
  display: flex;
  align-items: center;
  padding-top: 5rem;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  top: -50%;
  right: -20%;
  width: 800px;
  height: 800px;
  background: radial-gradient(circle, var(--accent-cyan-dim) 0%, transparent 70%);
  filter: blur(60px);
  animation: pulse-glow 8s ease-in-out infinite;
}

.hero::after {
  content: "";
  position: absolute;
  bottom: -30%;
  left: -10%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, var(--accent-amber-dim) 0%, transparent 70%);
  filter: blur(80px);
  animation: pulse-glow 10s ease-in-out infinite reverse;
}

@keyframes pulse-glow {
  0%, 100% { transform: scale(1); opacity: 0.6; }
  50% { transform: scale(1.1); opacity: 0.9; }
}

.hero-inner {
  max-width: 1400px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 4rem;
  align-items: center;
  width: 100%;
  padding: 0 2rem;
  position: relative;
  z-index: 2;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  border-radius: 9999px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--accent-cyan);
  font-size: 0.875rem;
  font-weight: 500;
  margin-bottom: 1.5rem;
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 1.5rem;
}

.hero-title .line-2 {
  display: block;
  background: linear-gradient(135deg, var(--accent-cyan) 0%, var(--accent-amber) 50%, var(--accent-violet) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-desc {
  color: var(--text-secondary);
  font-size: 1.125rem;
  max-width: 55ch;
  margin-bottom: 2rem;
}

.hero-cta {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.875rem 1.75rem;
  border-radius: 9999px;
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  transition: all 0.2s;
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-cyan), #0891b2);
  color: var(--bg-primary);
  box-shadow: 0 10px 30px -10px rgba(34, 211, 238, 0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 15px 40px -10px rgba(34, 211, 238, 0.5);
}

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

.btn-ghost:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-strong);
}

.hero-stats {
  display: flex;
  gap: 2rem;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
}

.hero-stat {
  display: flex;
  flex-direction: column;
}

.hero-stat-value {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text-primary);
}

.hero-stat-label {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.hero-visual {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-portrait {
  width: 380px;
  height: 480px;
  object-fit: cover;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  position: relative;
  z-index: 2;
  filter: grayscale(30%) contrast(1.1);
}

.portrait-frame {
  position: absolute;
  inset: -20px;
  border: 1px solid var(--accent-cyan);
  border-radius: calc(var(--radius-lg) + 10px);
  opacity: 0.3;
  z-index: 1;
}

.portrait-orb {
  position: absolute;
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: radial-gradient(circle, var(--accent-cyan) 0%, transparent 70%);
  filter: blur(30px);
  animation: float 6s ease-in-out infinite;
}

.portrait-orb:nth-child(3) {
  top: 10%;
  right: 5%;
  background: radial-gradient(circle, var(--accent-amber) 0%, transparent 70%);
  animation-delay: -2s;
}

.portrait-orb:nth-child(4) {
  bottom: 15%;
  left: 0;
  background: radial-gradient(circle, var(--accent-violet) 0%, transparent 70%);
  animation-delay: -4s;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-20px); }
}

/* Cards */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  transition: all 0.3s;
  position: relative;
  overflow: hidden;
}

.card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent-cyan), transparent);
  opacity: 0;
  transition: opacity 0.3s;
}

.card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-strong);
  transform: translateY(-4px);
}

.card:hover::before {
  opacity: 0.5;
}

.card-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.card-text {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* Path section */
.path-track {
  position: relative;
  padding-left: 2rem;
}

.path-line {
  position: absolute;
  left: 1rem;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(180deg, var(--accent-emerald), var(--accent-cyan), var(--accent-amber), var(--accent-rose), var(--accent-violet));
}

.stage-item {
  position: relative;
  padding: 2rem 0 2rem 3rem;
  cursor: pointer;
  transition: all 0.3s;
}

.stage-item::before {
  content: "";
  position: absolute;
  left: -0.65rem;
  top: 2.5rem;
  width: 1.3rem;
  height: 1.3rem;
  border-radius: 50%;
  background: var(--bg-secondary);
  border: 3px solid var(--accent-cyan);
  transition: all 0.3s;
  z-index: 2;
}

.stage-item.active::before,
.stage-item:hover::before {
  background: var(--accent-cyan);
  box-shadow: 0 0 20px var(--accent-cyan);
}

.stage-item.completed::before {
  background: var(--accent-emerald);
  border-color: var(--accent-emerald);
}

.stage-header {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  margin-bottom: 0.5rem;
}

.stage-number {
  font-size: 0.875rem;
  color: var(--text-muted);
  font-weight: 600;
}

.stage-name {
  font-size: 1.5rem;
  font-weight: 700;
}

.stage-meta {
  display: flex;
  gap: 1rem;
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.stage-desc {
  color: var(--text-secondary);
  max-width: 70ch;
}

.stage-detail {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.5s ease, opacity 0.3s;
  opacity: 0;
}

.stage-item.active .stage-detail {
  max-height: 800px;
  opacity: 1;
  margin-top: 1.5rem;
}

.course-list {
  display: grid;
  gap: 0.75rem;
  margin-top: 1rem;
}

.course-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem;
  background: rgba(0, 0, 0, 0.2);
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.course-info h4 {
  font-size: 1rem;
  margin-bottom: 0.25rem;
}

.course-info p {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.course-hours {
  font-size: 0.8rem;
  color: var(--accent-cyan);
  background: var(--accent-cyan-dim);
  padding: 0.25rem 0.75rem;
  border-radius: 9999px;
}

/* Axioms grid */
.axioms-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.25rem;
}

.axiom-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  transition: all 0.3s;
}

.axiom-card:hover {
  border-color: var(--accent-cyan);
  background: var(--bg-card-hover);
}

.taboo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.taboo-card {
  background: rgba(244, 63, 94, 0.05);
  border: 1px solid rgba(244, 63, 94, 0.28);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  transition: all 0.3s;
}

.taboo-card:hover {
  background: rgba(244, 63, 94, 0.09);
  border-color: var(--accent-rose);
  transform: translateY(-3px);
}

.taboo-name {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--accent-rose);
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.taboo-name::before {
  content: "⛔";
  font-size: 1.1rem;
}

.taboo-desc {
  color: var(--text-secondary);
  line-height: 1.7;
  font-size: 0.95rem;
}

.axiom-number {
  width: 2rem;
  height: 2rem;
  border-radius: 50%;
  background: var(--accent-cyan-dim);
  color: var(--accent-cyan);
  display: grid;
  place-items: center;
  font-weight: 700;
  font-size: 0.875rem;
  margin-bottom: 1rem;
}

.axiom-name {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.axiom-physics {
  font-size: 0.85rem;
  color: var(--accent-cyan);
  margin-bottom: 0.75rem;
}

.axiom-detail {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* Dashboard */
.dashboard-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.dashboard-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
}

.dashboard-card-label {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.dashboard-card-value {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.dashboard-card-sub {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.progress-bar {
  height: 8px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 9999px;
  overflow: hidden;
  margin-top: 1rem;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent-cyan), var(--accent-amber));
  border-radius: 9999px;
  transition: width 1s ease;
}

/* Community */
.discussion-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.discussion-item {
  display: flex;
  gap: 1rem;
  padding: 1.25rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  transition: all 0.2s;
}

.discussion-item:hover {
  background: var(--bg-card-hover);
}

.discussion-avatar {
  width: 2.75rem;
  height: 2.75rem;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-violet));
  display: grid;
  place-items: center;
  font-weight: 700;
  color: var(--bg-primary);
  flex-shrink: 0;
}

.discussion-content {
  flex: 1;
}

.discussion-title {
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.discussion-meta {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.discussion-stats {
  display: flex;
  gap: 1rem;
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.discussion-form {
  display: flex;
  gap: 1rem;
  margin-top: 2rem;
}

.discussion-input {
  flex: 1;
  padding: 1rem 1.25rem;
  background: rgba(0, 0, 0, 0.3);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 0.95rem;
}

.discussion-input:focus {
  outline: none;
  border-color: var(--accent-cyan);
}

/* Instructor */
.instructor-grid {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: 4rem;
  align-items: center;
}

.instructor-image {
  position: relative;
}

.instructor-image img {
  width: 100%;
  max-width: 400px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.instructor-name {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.instructor-title {
  color: var(--accent-cyan);
  font-size: 1.1rem;
  margin-bottom: 1.5rem;
}

.instructor-bio {
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 1.5rem;
}

/* Safety */
.safety-banner {
  background: linear-gradient(135deg, rgba(239, 68, 68, 0.15), rgba(239, 68, 68, 0.05));
  border: 1px solid rgba(239, 68, 68, 0.3);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin-bottom: 3rem;
}

.safety-banner h3 {
  color: #f87171;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.safety-banner p {
  color: var(--text-secondary);
  line-height: 1.8;
}

/* Global fictional-setting disclaimer bar (first screen) */
.disclaimer-bar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  padding: 0.5rem 3rem 0.5rem 1rem;
  background: linear-gradient(90deg, rgba(239, 68, 68, 0.95), rgba(245, 158, 11, 0.95));
  color: #fff;
  font-size: 0.82rem;
  line-height: 1.45;
  text-align: center;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.3);
}

.disclaimer-bar svg {
  flex: 0 0 auto;
}

.disclaimer-bar span {
  flex: 1 1 auto;
}

.disclaimer-close {
  position: absolute;
  right: 0.75rem;
  top: 50%;
  transform: translateY(-50%);
  background: transparent;
  border: 0;
  color: #fff;
  font-size: 1rem;
  line-height: 1;
  cursor: pointer;
  padding: 0.25rem 0.5rem;
  opacity: 0.85;
}

.disclaimer-close:hover {
  opacity: 1;
}

body.has-disclaimer {
  padding-top: var(--disclaimer-h, 40px);
}

body.has-disclaimer .nav {
  top: var(--disclaimer-h, 40px);
}

/* Science Behind the Fiction */
.science-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.science-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
}

.science-card p {
  color: var(--text-secondary);
  line-height: 1.8;
  margin: 0.75rem 0 0;
}

.science-tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 0.2rem 0.6rem;
  border-radius: 9999px;
  background: rgba(34, 211, 238, 0.15);
  color: var(--accent-cyan);
}

.science-tag-fiction {
  background: rgba(167, 139, 250, 0.15);
  color: var(--accent-violet);
}

.science-link {
  text-align: center;
  margin-top: 0.5rem;
}

.science-link a {
  color: var(--accent-amber);
  font-weight: 600;
  text-decoration: none;
}

.science-link a:hover {
  text-decoration: underline;
}

/* Footer */
.footer {
  border-top: 1px solid var(--border);
  padding: 3rem 2rem;
  background: var(--bg-secondary);
  position: relative;
  z-index: 1;
}

.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-text {
  color: var(--text-muted);
  font-size: 0.875rem;
}

.footer-domain {
  color: var(--accent-cyan);
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-decoration: none;
  padding: 0.35rem 0.85rem;
  border: 1px solid var(--border);
  border-radius: 9999px;
  background: var(--bg-card);
  transition: border-color 0.25s, color 0.25s;
}

.footer-domain:hover {
  border-color: var(--accent-cyan);
  color: var(--accent-amber);
}

.footer-copy {
  flex-basis: 100%;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.8rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--border);
  margin: 0;
}

/* Brand lockup */
.logo-text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
  font-family: var(--font-display);
  letter-spacing: 0.01em;
}

.logo-text em {
  font-style: normal;
  font-size: 0.6em;
  font-weight: 500;
  color: var(--text-secondary);
  letter-spacing: 0.06em;
}

.hero-brand {
  font-family: var(--font-display);
  font-size: clamp(1.1rem, 2.4vw, 1.5rem);
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--text-secondary);
  margin: -0.75rem 0 1.5rem;
}

.hero-brand .accent {
  color: var(--accent-amber);
}

@media (max-width: 768px) {
  .logo-text {
    font-size: 1rem;
  }

  .footer-inner {
    justify-content: center;
    text-align: center;
  }
}

/* Utility */
.hidden {
  display: none !important;
}

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

.mb-4 {
  margin-bottom: 1rem;
}

.mb-8 {
  margin-bottom: 2rem;
}

.mt-8 {
  margin-top: 2rem;
}


/* WeChat contact card */
.wechat-card {
  margin-top: 2.5rem;
  padding: 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  gap: 1.5rem;
  text-align: left;
  transition: all 0.3s;
}

.wechat-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-strong);
}

.wechat-info {
  flex: 1;
}

.wechat-info h4 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  color: var(--accent-cyan);
}

.wechat-info p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

.wechat-qr {
  width: 120px;
  height: 120px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  flex-shrink: 0;
}

/* Animations */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  animation: fade-in 0.8s forwards;
}

@keyframes fade-in {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Responsive */
@media (max-width: 1024px) {
  .hero-inner {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-stats {
    justify-content: center;
  }

  .hero-cta {
    justify-content: center;
  }

  .hero-visual {
    order: -1;
  }

  .hero-portrait {
    width: 280px;
    height: 360px;
  }


  .instructor-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .instructor-image {
    order: -1;
  }

  .instructor-image img {
    margin: 0 auto;
  }

  .wechat-card {
    flex-direction: column;
    text-align: center;
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--bg-secondary);
    padding: 1rem 2rem;
    border-bottom: 1px solid var(--border);
    gap: 1rem;
  }

  .nav-links.open {
    display: flex;
  }

  .mobile-menu-btn {
    display: block;
  }

  .section {
    padding: 4rem 1.5rem;
  }

  .hero {
    padding-top: 6rem;
  }

  .discussion-form {
    flex-direction: column;
  }

  .course-item {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
  }

  .wechat-qr {
    width: 140px;
    height: 140px;
  }
}