/* ==========================================
   CSS Variables & Reset
   ========================================== */
:root {
  --primary: #6366f1;
  --primary-dark: #4f46e5;
  --primary-light: #8b5cf6;
  --accent: #a78bfa;
  --bg: #0f0f1a;
  --bg-alt: #1a1a2e;
  --bg-card: rgba(255, 255, 255, 0.04);
  --bg-card-hover: rgba(255, 255, 255, 0.08);
  --text: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --border: rgba(255, 255, 255, 0.08);
  --border-light: rgba(255, 255, 255, 0.12);
  --success: #22c55e;
  --success-bg: rgba(34, 197, 94, 0.12);
  --error: #ef4444;
  --error-bg: rgba(239, 68, 68, 0.12);
  --radius-sm: 8px;
  --radius: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.4);
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 20% 10%, rgba(99, 102, 241, 0.06), transparent),
    radial-gradient(ellipse 60% 40% at 80% 60%, rgba(139, 92, 246, 0.05), transparent),
    radial-gradient(ellipse 50% 50% at 50% 80%, rgba(99, 102, 241, 0.03), transparent);
  z-index: 0;
  pointer-events: none;
}

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

.section {
  padding: 100px 0;
  position: relative;
  z-index: 1;
}

.section-header {
  text-align: center;
  margin-bottom: 60px;
}

.section-tag {
  display: inline-block;
  padding: 6px 16px;
  background: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.25);
  border-radius: 50px;
  font-size: 13px;
  font-weight: 600;
  color: var(--primary-light);
  margin-bottom: 16px;
}

.section-header h2 {
  font-size: 36px;
  font-weight: 800;
  margin-bottom: 12px;
  background: linear-gradient(135deg, #f1f5f9, #cbd5e1);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-header p {
  font-size: 16px;
  color: var(--text-muted);
}

/* ==========================================
   Header / Navbar
   ========================================== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  transition: var(--transition);
  padding: 16px 0;
}

.header.scrolled {
  background: rgba(15, 15, 26, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  padding: 10px 0;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo, .footer-logo {
  font-size: 20px;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  background: linear-gradient(135deg, #818cf8, #a78bfa);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: flex;
  align-items: center;
  gap: 8px;
}

.logo-icon {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid var(--primary);
  flex-shrink: 0;
}

.nav {
  display: flex;
  gap: 8px;
}

.nav-link {
  padding: 8px 18px;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  border-radius: 8px;
  transition: var(--transition);
}

.nav-link:hover,
.nav-link.active {
  color: var(--text);
  background: rgba(99, 102, 241, 0.12);
}

/* Mute Button */
.mute-btn {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  border: 1.5px solid var(--border-light);
  background: rgba(255, 255, 255, 0.06);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
  padding: 0;
  margin-right: 8px;
}

.mute-btn:hover {
  border-color: var(--primary);
  background: rgba(99, 102, 241, 0.2);
  transform: scale(1.1);
}

.mute-icon {
  font-size: 16px;
  line-height: 1;
}

/* Hamburger */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.menu-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: var(--transition);
}

.menu-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.menu-toggle.open span:nth-child(2) { opacity: 0; }
.menu-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ==========================================
   Buttons
   ========================================== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 50px;
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  border: none;
  transition: var(--transition);
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  color: #fff;
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(99, 102, 241, 0.5);
}

.btn-outline {
  background: transparent;
  color: var(--text);
  border: 1.5px solid var(--border-light);
}

.btn-outline:hover {
  background: rgba(255, 255, 255, 0.05);
  border-color: var(--primary);
}

.submit-btn {
  width: 100%;
  justify-content: center;
}

.submit-btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

.btn-loading { display: flex; align-items: center; gap: 8px; }

.spinner {
  width: 18px; height: 18px;
  border: 2px solid rgba(255,255,255,0.3);
  border-top-color: #fff;
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

/* ==========================================
   Danmaku (弹幕)
   ========================================== */
.danmaku-area {
  position: fixed;
  top: 64px;
  left: 0;
  right: 0;
  height: 120px;
  z-index: 999;
  pointer-events: none;
  overflow: hidden;
}

.danmaku-item {
  position: absolute;
  white-space: nowrap;
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 14px;
  font-weight: 500;
  background: rgba(99, 102, 241, 0.25);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(99, 102, 241, 0.3);
  color: #e2e8f0;
  animation: danmaku-scroll linear forwards;
  pointer-events: auto;
  cursor: default;
}

.danmaku-item:hover {
  background: rgba(99, 102, 241, 0.45);
  border-color: var(--primary-light);
}

.danmaku-nick {
  color: var(--primary-light);
  font-weight: 700;
  margin-right: 6px;
}

@keyframes danmaku-scroll {
  from { transform: translateX(105vw); }
  to   { transform: translateX(-100%); }
}
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 120px 0 80px;
  position: relative;
  z-index: 1;
}

.hero .container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.hero-badge {
  display: inline-block;
  padding: 6px 16px;
  background: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.25);
  border-radius: 50px;
  font-size: 13px;
  font-weight: 600;
  color: var(--primary-light);
  margin-bottom: 24px;
}

.hero-content h1 {
  font-size: 56px;
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 24px;
  background: linear-gradient(135deg, #f1f5f9 0%, #818cf8 50%, #a78bfa 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-desc {
  font-size: 17px;
  color: var(--text-muted);
  line-height: 1.8;
  margin-bottom: 36px;
  max-width: 480px;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

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

.hero-card {
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  text-align: center;
  position: relative;
  z-index: 2;
  width: 220px;
}

.hero-card.secondary {
  position: absolute;
  top: -30px;
  right: -20px;
  z-index: 1;
  opacity: 0.7;
  transform: scale(0.85);
}

.hero-card-icon { font-size: 48px; margin-bottom: 12px; }
.hero-card-title { font-size: 18px; font-weight: 700; margin-bottom: 4px; }
.hero-card-desc { font-size: 14px; color: var(--text-muted); }

.hero-glow {
  position: absolute;
  width: 300px; height: 300px;
  background: radial-gradient(circle, rgba(99, 102, 241, 0.15), transparent 70%);
  border-radius: 50%;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  pointer-events: none;
}

/* ==========================================
   Posts Feed - 抖音帖子风格
   ========================================== */
.posts {
  background: var(--bg-alt);
}

.posts-feed {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.post-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: var(--transition);
}

.post-card:hover {
  border-color: var(--primary);
  background: var(--bg-card-hover);
}

.post-media {
  width: 100%;
  background: #111;
  overflow: hidden;
}

.post-media img,
.post-media video {
  width: 100%;
  height: auto;
  display: block;
  max-height: 500px;
  object-fit: contain;
}

.post-info {
  padding: 14px 18px 16px;
}

.post-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 8px;
}

.post-body {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.9;
  margin-bottom: 10px;
}

.post-meta {
  font-size: 12px;
  color: var(--text-muted);
}

/* ==========================================
   Features Section
   ========================================== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  transition: var(--transition);
}

.feature-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--primary);
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.feature-icon {
  font-size: 40px;
  margin-bottom: 20px;
}

.feature-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 10px;
}

.feature-card p {
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.7;
}

/* ==========================================
   About Section
   ========================================== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.about-text h2 {
  font-size: 36px;
  font-weight: 800;
  line-height: 1.3;
  margin-bottom: 20px;
  background: linear-gradient(135deg, #f1f5f9, #cbd5e1);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.about-text p {
  font-size: 16px;
  color: var(--text-muted);
  line-height: 1.8;
  margin-bottom: 24px;
}

.about-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.about-list li {
  font-size: 15px;
  color: var(--text-secondary);
}

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

.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px 24px;
  text-align: center;
  transition: var(--transition);
}

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

.stat-number {
  display: block;
  font-size: 36px;
  font-weight: 800;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 8px;
}

.stat-label {
  font-size: 14px;
  color: var(--text-muted);
}

/* ==========================================
   Evaluate Section
   ========================================== */
.evaluate {
  background: var(--bg-alt);
}

.evaluate-wrapper {
  max-width: 600px;
  margin: 0 auto;
}

.evaluate-form {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  margin-bottom: 24px;
}

.form-group {
  margin-bottom: 20px;
  position: relative;
}

.form-group label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text);
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 12px 16px;
  background: rgba(255, 255, 255, 0.05);
  border: 1.5px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-size: 15px;
  font-family: inherit;
  transition: var(--transition);
  outline: none;
}

.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--primary);
  background: rgba(99, 102, 241, 0.08);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.12);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
  color: rgba(148, 163, 184, 0.45);
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

.char-count {
  display: block;
  text-align: right;
  font-size: 12px;
  color: var(--text-muted);
  margin-top: 4px;
}

.success-msg {
  background: var(--success-bg);
  border: 1px solid rgba(34, 197, 94, 0.25);
  border-radius: var(--radius-lg);
  padding: 32px 24px;
  text-align: center;
  margin-bottom: 24px;
}

.success-icon { font-size: 48px; margin-bottom: 12px; }

.success-msg h3 {
  font-size: 20px;
  color: var(--success);
  margin-bottom: 8px;
}

.success-msg p {
  font-size: 14px;
  color: var(--text-muted);
}

.evaluations-panel {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
}

.panel-title {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 18px;
  color: var(--text);
}

.evaluations-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.evaluation-item {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  transition: var(--transition);
}

.evaluation-item:hover {
  border-color: var(--primary);
  background: rgba(99, 102, 241, 0.05);
}

.evaluation-item .eval-nickname {
  font-size: 14px;
  font-weight: 600;
  color: var(--primary-light);
  margin-bottom: 8px;
}

.evaluation-item .eval-content {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

.evaluation-item .eval-time {
  font-size: 12px;
  color: var(--text-muted);
  margin-top: 10px;
}

.empty-text {
  text-align: center;
  color: var(--text-muted);
  font-size: 14px;
  padding: 24px 0;
}

/* ==========================================
   Footer
   ========================================== */
.footer {
  border-top: 1px solid var(--border);
  padding: 60px 0 30px;
  position: relative;
  z-index: 1;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand p {
  color: var(--text-muted);
  font-size: 14px;
  margin-top: 12px;
  max-width: 280px;
}

.footer-links h4 {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--text);
}

.footer-links a {
  display: block;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 14px;
  padding: 5px 0;
  transition: var(--transition);
}

.footer-links a:hover { color: var(--primary-light); }

.footer-bottom {
  text-align: center;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}

.footer-bottom p {
  font-size: 13px;
  color: var(--text-muted);
}

/* ==========================================
   Toast
   ========================================== */
.toast {
  position: fixed;
  top: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(-120px);
  padding: 14px 28px;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border);
  border-radius: 50px;
  color: var(--text);
  font-size: 14px;
  z-index: 9999;
  transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  pointer-events: none;
}

.toast.show { transform: translateX(-50%) translateY(0); }

.toast.success {
  border-color: rgba(34, 197, 94, 0.3);
  background: var(--success-bg);
}

.toast.error {
  border-color: rgba(239, 68, 68, 0.3);
  background: var(--error-bg);
}

/* ==========================================
   Animation (On Scroll Reveal)
   ========================================== */
.fade-up {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ==========================================
   Responsive
   ========================================== */
@media (max-width: 1024px) {
  .hero .container {
    grid-template-columns: 1fr;
    text-align: center;
  }
  .hero-actions { justify-content: center; }
  .hero-desc { max-width: 100%; }
  .hero-content h1 { font-size: 42px; }
  .hero-visual { margin-top: 40px; }
  .hero-card.secondary { display: none; }
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .about-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  .section { padding: 60px 0; }
  .section-header h2 { font-size: 28px; }
  .hero-content h1 { font-size: 32px; }
  .hero-desc { font-size: 15px; }
  .about-text h2 { font-size: 28px; }

  .nav {
    position: fixed;
    top: 0; right: -100%;
    width: 260px; height: 100vh;
    background: rgba(15, 15, 26, 0.98);
    backdrop-filter: blur(20px);
    flex-direction: column;
    padding: 80px 24px 24px;
    gap: 4px;
    transition: var(--transition);
    border-left: 1px solid var(--border);
  }
  .nav.open { right: 0; }
  .nav-link { padding: 12px 16px; font-size: 16px; border-radius: var(--radius); }
  .menu-toggle { display: flex; position: relative; z-index: 1001; }

  .features-grid { grid-template-columns: 1fr; }
  .about-stats { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 30px; }
  .hero-card { width: 180px; }
}

@media (max-width: 480px) {
  .container { padding: 0 16px; }
  .hero-content h1 { font-size: 28px; }
  .btn { padding: 10px 22px; font-size: 14px; }
  .evaluate-form { padding: 20px 16px; }
  .section-header h2 { font-size: 24px; }
}