:root {
  --primary-color: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-light: #3b82f6;
  --secondary-color: #64748b;
  --success-color: #10b981;
  --warning-color: #f59e0b;
  --danger-color: #ef4444;
  --background: #f8fafc;
  --surface: #ffffff;
  --border: #e2e8f0;
  --text-primary: #1e293b;
  --text-secondary: #64748b;
  --text-muted: #94a3b8;
  --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --radius: 12px;
  --radius-sm: 8px;
  --radius-lg: 16px;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background-color: var(--background);
  color: var(--text-primary);
  line-height: 1.6;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

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

.header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
  gap: 20px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--text-primary);
}

.logo-icon {
  font-size: 1.8rem;
}

.logo-text {
  background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

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

.nav-link {
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-weight: 500;
  transition: all 0.2s;
}

.nav-link:hover {
  color: var(--primary-color);
  background: rgba(37, 99, 235, 0.08);
}

.nav-link.active {
  color: var(--primary-color);
  background: rgba(37, 99, 235, 0.1);
}

.user-area {
  display: flex;
  align-items: center;
  gap: 12px;
}

.mobile-menu-btn {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
  background: none;
  border: none;
  cursor: pointer;
}

.mobile-menu-btn span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: all 0.3s;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 20px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all 0.2s;
  border: 2px solid transparent;
}

.btn-primary {
  background: var(--primary-color);
  color: white;
  border-color: var(--primary-color);
}

.btn-primary:hover {
  background: var(--primary-dark);
  border-color: var(--primary-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow);
}

.btn-secondary {
  background: var(--surface);
  color: var(--text-primary);
  border-color: var(--border);
}

.btn-secondary:hover {
  border-color: var(--primary-color);
  color: var(--primary-color);
}

.btn-outline {
  background: transparent;
  color: var(--primary-color);
  border-color: var(--primary-color);
}

.btn-outline:hover {
  background: var(--primary-color);
  color: white;
}

.btn-lg {
  padding: 14px 28px;
  font-size: 1.05rem;
}

.btn-sm {
  padding: 6px 14px;
  font-size: 0.85rem;
}

.btn-block {
  width: 100%;
}

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

.btn-icon {
  font-size: 1.1em;
}

.hero {
  padding: 80px 0;
  background: linear-gradient(135deg, #eff6ff 0%, #f0fdf4 100%);
  text-align: center;
}

.hero-title {
  font-size: 3rem;
  font-weight: 800;
  margin-bottom: 20px;
  background: linear-gradient(135deg, var(--text-primary), var(--primary-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 40px;
}

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

.section-title {
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 40px;
  color: var(--text-primary);
}

.features {
  padding: 80px 0;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 24px;
}

.feature-card {
  background: var(--surface);
  padding: 32px;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  text-align: center;
  transition: all 0.3s;
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.feature-icon {
  font-size: 3rem;
  margin-bottom: 20px;
}

.feature-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.feature-desc {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.steps {
  padding: 80px 0;
  background: var(--surface);
}

.step-grid {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.step-card {
  background: var(--background);
  padding: 24px;
  border-radius: var(--radius);
  text-align: center;
  min-width: 180px;
}

.step-number {
  width: 48px;
  height: 48px;
  background: var(--primary-color);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: 700;
  margin: 0 auto 16px;
}

.step-title {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.step-desc {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.step-arrow {
  font-size: 1.5rem;
  color: var(--primary-color);
  font-weight: 700;
}

.cta {
  padding: 80px 0;
  background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
}

.cta-content {
  text-align: center;
  color: white;
}

.cta-title {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 16px;
}

.cta-desc {
  font-size: 1.1rem;
  opacity: 0.9;
  margin-bottom: 32px;
}

.vip-preview {
  padding: 80px 0;
}

.vip-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.vip-card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 32px;
  box-shadow: var(--shadow);
  text-align: center;
  border: 2px solid var(--border);
}

.vip-card.recommended {
  border-color: var(--primary-color);
  position: relative;
}

.vip-badge {
  display: inline-block;
  padding: 6px 16px;
  border-radius: 20px;
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 20px;
  background: var(--background);
  color: var(--text-secondary);
}

.vip-badge.monthly {
  background: #fef3c7;
  color: #d97706;
}

.vip-badge.yearly {
  background: #dbeafe;
  color: #2563eb;
}

.savings {
  background: var(--danger-color);
  color: white;
  padding: 4px 12px;
  border-radius: 12px;
  font-size: 0.8rem;
  font-weight: 600;
  position: absolute;
  top: -10px;
  right: 20px;
}

.vip-features {
  list-style: none;
  margin: 24px 0;
  text-align: left;
}

.vip-features li {
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 10px;
}

.vip-features li:last-child {
  border-bottom: none;
}

.vip-features .check {
  color: var(--success-color);
  font-weight: 700;
}

.footer {
  background: var(--text-primary);
  color: white;
  padding: 40px 0;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 20px;
}

.footer-info p {
  opacity: 0.8;
}

.footer-links {
  display: flex;
  gap: 24px;
}

.footer-links a {
  opacity: 0.8;
  transition: opacity 0.2s;
}

.footer-links a:hover {
  opacity: 1;
}

.main {
  min-height: calc(100vh - 140px);
  padding: 40px 0;
}

.page-title {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.page-desc {
  color: var(--text-secondary);
  font-size: 1.05rem;
}

.section-subtitle {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 20px;
  color: var(--text-primary);
}

@media (max-width: 768px) {
  .header-content {
    height: 60px;
  }
  
  .nav {
    display: none;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--surface);
    flex-direction: column;
    padding: 16px;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow);
  }
  
  .nav.show {
    display: flex;
  }
  
  .mobile-menu-btn {
    display: flex;
  }
  
  .hero {
    padding: 40px 0;
  }
  
  .hero-title {
    font-size: 2rem;
  }
  
  .hero-subtitle {
    font-size: 1rem;
  }
  
  .hero-actions {
    flex-direction: column;
    padding: 0 20px;
  }
  
  .section-title {
    font-size: 1.5rem;
  }
  
  .step-grid {
    flex-direction: column;
  }
  
  .step-arrow {
    transform: rotate(90deg);
  }
  
  .footer-content {
    flex-direction: column;
    text-align: center;
  }
}