/* CSS Variables */
:root {
  --primary-color: #FF6B35;
  --primary-hover: #ff8533;
  --primary-light: rgba(255, 107, 53, 0.1);

  /* Light theme */
  --bg-primary: #FFFFFF;
  --bg-secondary: #F9FAFB;
  --bg-card: #FFFFFF;
  --text-primary: #1F2937;
  --text-secondary: #6B7280;
  --border-color: #E5E7EB;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
  --bg-primary: #0B0B0B;
  --bg-secondary: #1A1A1A;
  --bg-card: #262626;
  --text-primary: #FFFFFF;
  --text-secondary: #9CA3AF;
  --border-color: #404040;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
}

/* Reset & Base */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Noto Sans SC', 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background-color 0.3s ease, color 0.3s ease;
}

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

/* Navbar */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  transition: background 0.3s ease;
}

[data-theme="dark"] .navbar {
  background: rgba(11, 11, 11, 0.8);
}

.navbar-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 24px;
  font-weight: 700;
  color: var(--primary-color);
  text-decoration: none;
}

.logo svg {
  width: 32px;
  height: 32px;
}

.navbar-right {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* Language Selector */
.language-selector {
  position: relative;
}

.language-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  color: var(--text-primary);
  font-size: 14px;
  cursor: pointer;
  transition: all 0.2s ease;
}

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

.arrow-icon {
  width: 16px;
  height: 16px;
  transition: transform 0.2s ease;
}

.language-selector.active .arrow-icon {
  transform: rotate(180deg);
}

.language-dropdown {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  box-shadow: var(--shadow-lg);
  min-width: 140px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-8px);
  transition: all 0.2s ease;
}

.language-selector.active .language-dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.language-option {
  display: flex;
  align-items: center;
  gap: 8px;
  width: 100%;
  padding: 10px 14px;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 14px;
  cursor: pointer;
  transition: background 0.2s ease;
}

.language-option:hover {
  background: var(--bg-secondary);
}

.language-option.active {
  color: var(--primary-color);
}

.check-icon {
  width: 16px;
  text-align: center;
}

/* Theme Toggle */
.theme-toggle {
  width: 40px;
  height: 40px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  font-size: 18px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.theme-toggle:hover {
  border-color: var(--primary-color);
  transform: scale(1.05);
}

/* Hero Section */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 100px 24px 60px;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--primary-light) 0%, transparent 50%);
  opacity: 0.5;
}

[data-theme="dark"] .hero-bg {
  background: linear-gradient(135deg, rgba(255, 107, 53, 0.15) 0%, transparent 50%);
}

.hero-content {
  position: relative;
  text-align: center;
  max-width: 800px;
  animation: fadeInUp 0.8s ease;
}

.hero-title {
  font-size: clamp(32px, 6vw, 56px);
  font-weight: 700;
  margin-bottom: 20px;
  background: linear-gradient(135deg, var(--primary-color), #ff8533);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: clamp(16px, 2.5vw, 20px);
  color: var(--text-secondary);
  margin-bottom: 16px;
}

.hero-description {
  font-size: 16px;
  color: var(--text-secondary);
  margin-bottom: 40px;
}

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

.hero-glow {
  position: absolute;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, var(--primary-color) 0%, transparent 70%);
  opacity: 0.15;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  pointer-events: none;
  animation: pulse 4s ease-in-out infinite;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  font-size: 16px;
  font-weight: 600;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.3s ease;
}

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

.btn-primary:hover {
  background: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(255, 107, 53, 0.3);
}

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

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

.btn-large {
  padding: 16px 32px;
  font-size: 18px;
}

/* Section Title */
.section-title {
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 700;
  text-align: center;
  margin-bottom: 48px;
  color: var(--text-primary);
}

/* Features Section */
.features {
  padding: 80px 0;
  background: var(--bg-secondary);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  padding: 32px 24px;
  border-radius: 16px;
  text-align: center;
  border: 1px solid var(--border-color);
  transition: all 0.3s ease;
}

.feature-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary-color);
}

.feature-icon {
  font-size: 48px;
  margin-bottom: 16px;
}

.feature-name {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text-primary);
}

.feature-desc {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* Scenarios Section */
.scenarios {
  padding: 80px 0;
}

.scenarios-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.scenario-card {
  background: var(--bg-card);
  padding: 32px 24px;
  border-radius: 16px;
  text-align: center;
  border: 1px solid var(--border-color);
  transition: all 0.3s ease;
}

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

.scenario-icon {
  font-size: 48px;
  margin-bottom: 16px;
}

.scenario-name {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text-primary);
}

.scenario-desc {
  font-size: 14px;
  color: var(--text-secondary);
}

/* Process Section */
.process {
  padding: 80px 0;
  background: var(--bg-secondary);
}

.process-steps {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 24px;
  flex-wrap: wrap;
}

.process-step {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.step-number {
  width: 32px;
  height: 32px;
  background: var(--primary-color);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 14px;
}

.step-icon {
  width: 80px;
  height: 80px;
  background: var(--bg-card);
  border: 2px solid var(--border-color);
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 36px;
  transition: all 0.3s ease;
}

.process-step:hover .step-icon {
  border-color: var(--primary-color);
  transform: scale(1.05);
}

.step-text {
  font-size: 16px;
  font-weight: 500;
  color: var(--text-primary);
}

.process-arrow {
  font-size: 24px;
  color: var(--primary-color);
}

/* Download Section */
.download {
  padding: 80px 0;
}

.download-buttons {
  display: flex;
  gap: 24px;
  justify-content: center;
  flex-wrap: wrap;
}

/* FAQ Section */
.faq {
  padding: 80px 0;
  background: var(--bg-secondary);
}

.faq-list {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  margin-bottom: 16px;
  overflow: hidden;
  transition: all 0.3s ease;
}

.faq-item:hover {
  border-color: var(--primary-color);
}

.faq-question {
  width: 100%;
  padding: 20px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: none;
  border: none;
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  cursor: pointer;
  text-align: left;
}

.faq-icon {
  font-size: 24px;
  color: var(--primary-color);
  transition: transform 0.3s ease;
}

.faq-item.active .faq-icon {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
}

.faq-item.active .faq-answer {
  max-height: 200px;
}

.faq-answer p {
  padding: 0 24px 20px;
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.8;
}

/* Footer */
.footer {
  padding: 40px 0;
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
}

.footer-links {
  display: flex;
  gap: 32px;
  justify-content: center;
  flex-wrap: wrap;
}

.footer-links a,
.footer-links span {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 14px;
  transition: color 0.2s ease;
}

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

.footer-copyright {
  text-align: center;
  color: var(--text-secondary);
  font-size: 14px;
}

/* Modal */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.modal {
  background: var(--bg-card);
  border-radius: 16px;
  padding: 40px;
  text-align: center;
  max-width: 360px;
  width: 90%;
  position: relative;
  transform: scale(0.9);
  transition: transform 0.3s ease;
}

.modal-overlay.active .modal {
  transform: scale(1);
}

.modal-close {
  position: absolute;
  top: 16px;
  right: 16px;
  width: 32px;
  height: 32px;
  background: var(--bg-secondary);
  border: none;
  border-radius: 50%;
  font-size: 24px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.2s ease;
}

.modal-close:hover {
  background: var(--primary-color);
  color: white;
}

.modal-title {
  font-size: 24px;
  font-weight: 700;
  margin-bottom: 24px;
  color: var(--text-primary);
}

.qr-code {
  display: flex;
  justify-content: center;
  margin-bottom: 20px;
}

.qr-code img,
.qr-code canvas {
  border-radius: 8px;
}

.modal-hint {
  color: var(--text-secondary);
  font-size: 14px;
}

/* Animations */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes pulse {
  0%, 100% {
    opacity: 0.15;
    transform: translate(-50%, -50%) scale(1);
  }
  50% {
    opacity: 0.25;
    transform: translate(-50%, -50%) scale(1.1);
  }
}

/* Responsive */
@media (max-width: 1199px) {
  .features-grid,
  .scenarios-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 767px) {
  .navbar-container {
    padding: 12px 16px;
  }

  .navbar-right {
    gap: 8px;
  }

  .language-btn span:first-child {
    display: none;
  }

  .hero {
    padding: 80px 16px 40px;
  }

  .hero-buttons {
    flex-direction: column;
    align-items: center;
  }

  .btn {
    width: 100%;
    max-width: 280px;
  }

  .features,
  .scenarios,
  .process,
  .download,
  .faq {
    padding: 60px 0;
  }

  .section-title {
    margin-bottom: 32px;
  }

  .features-grid,
  .scenarios-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .process-steps {
    flex-direction: column;
  }

  .process-arrow {
    transform: rotate(90deg);
  }

  .download-buttons {
    flex-direction: column;
    align-items: center;
  }

  .footer-links {
    gap: 16px;
  }

  .modal {
    padding: 32px 24px;
  }

  .step-icon {
    width: 64px;
    height: 64px;
    font-size: 28px;
  }
}