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

:root {
  --primary-green: #1a4d2e;
  --deep-green: #0d2818;
  --accent-green: #2d6a4f;
  --light-green: #52b788;
  --gold: #d4af37;
  --bg-light: #f8f9fa;
  --text-dark: #1a1a1a;
  --text-gray: #4a5568;
  --white: #ffffff;
  --shadow: rgba(26, 77, 46, 0.15);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", sans-serif;
  line-height: 1.7;
  color: var(--text-dark);
  background: var(--bg-light);
}

.main-header {
  background: linear-gradient(135deg, var(--deep-green) 0%, var(--primary-green) 100%);
  padding: 1.2rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 4px 12px var(--shadow);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo-area img {
  display: block;
}

.nav-menu {
  display: flex;
  gap: 2.5rem;
  list-style: none;
}

.nav-menu a {
  color: var(--white);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s;
}

.nav-menu a:hover {
  color: var(--gold);
}

.quick-nav {
  position: fixed;
  right: 2rem;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
  z-index: 90;
}

.nav-item, .back-top {
  width: 48px;
  height: 48px;
  background: var(--white);
  border: 2px solid var(--primary-green);
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  color: var(--primary-green);
  transition: all 0.3s;
  box-shadow: 0 2px 8px var(--shadow);
}

.nav-item:hover, .back-top:hover {
  background: var(--primary-green);
  color: var(--white);
  transform: scale(1.1);
}

.hero-banner {
  background: linear-gradient(165deg, var(--primary-green) 0%, var(--accent-green) 50%, var(--light-green) 100%);
  padding: 5rem 2rem;
  color: var(--white);
  text-align: center;
}

.banner-content {
  max-width: 1000px;
  margin: 0 auto;
}

.banner-content h1 {
  font-size: 2.8rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
  text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
}

.banner-desc {
  font-size: 1.1rem;
  line-height: 1.9;
  margin-bottom: 2.5rem;
  opacity: 0.95;
}

.cta-buttons {
  display: flex;
  gap: 1.5rem;
  justify-content: center;
  margin-bottom: 2.5rem;
}

.btn-primary, .btn-secondary {
  padding: 1rem 2.5rem;
  font-size: 1.1rem;
  font-weight: 600;
  border: none;
  border-radius: 50px;
  cursor: pointer;
  transition: all 0.4s;
}

.btn-primary {
  background: var(--gold);
  color: var(--deep-green);
  box-shadow: 0 4px 15px rgba(212, 175, 55, 0.4);
  animation: pulse 2s infinite;
}

.btn-primary:hover {
  background: #f0c14b;
  transform: translateY(-3px);
  box-shadow: 0 6px 20px rgba(212, 175, 55, 0.6);
}

.btn-secondary {
  background: transparent;
  color: var(--white);
  border: 2px solid var(--white);
}

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

@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.05); }
}

.trust-indicators {
  display: flex;
  gap: 2rem;
  justify-content: center;
  flex-wrap: wrap;
}

.indicator {
  font-size: 0.95rem;
}

.indicator strong {
  color: var(--gold);
  font-size: 1.2rem;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

.value-props {
  padding: 4rem 2rem;
  background: var(--white);
}

.value-props .container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

.prop-card {
  background: linear-gradient(135deg, var(--bg-light) 0%, var(--white) 100%);
  padding: 2rem;
  border-radius: 12px;
  border-left: 4px solid var(--primary-green);
  box-shadow: 0 4px 12px var(--shadow);
  transition: transform 0.3s;
}

.prop-card:hover {
  transform: translateY(-5px);
}

.prop-card picture {
  display: block;
  margin-bottom: 1.5rem;
  border-radius: 8px;
  overflow: hidden;
}

.prop-card img {
  width: 100%;
  height: auto;
  display: block;
  transition: transform 0.3s;
}

.prop-card:hover img {
  transform: scale(1.05);
}

.prop-card h2 {
  font-size: 1.4rem;
  color: var(--primary-green);
  margin-bottom: 1rem;
}

.prop-card p {
  color: var(--text-gray);
  line-height: 1.7;
}

.section-title {
  font-size: 2.2rem;
  color: var(--primary-green);
  text-align: center;
  margin-bottom: 3rem;
  position: relative;
  padding-bottom: 1rem;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 80px;
  height: 4px;
  background: var(--gold);
  border-radius: 2px;
}

.features-section {
  padding: 5rem 2rem;
  background: var(--bg-light);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 2rem;
}

.feature-item {
  background: var(--white);
  padding: 2rem;
  border-radius: 10px;
  box-shadow: 0 3px 10px var(--shadow);
}

.feature-item h3 {
  color: var(--accent-green);
  font-size: 1.3rem;
  margin-bottom: 1rem;
}

.feature-item p {
  color: var(--text-gray);
}

.detection-scope {
  padding: 5rem 2rem;
  background: var(--white);
}

.scope-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
  gap: 3rem;
}

.scope-category h3 {
  color: var(--primary-green);
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  padding-left: 1rem;
  border-left: 4px solid var(--gold);
}

.scope-list {
  list-style: none;
}

.scope-list li {
  padding: 0.8rem 0;
  padding-left: 1.5rem;
  position: relative;
  color: var(--text-gray);
  border-bottom: 1px solid #e2e8f0;
}

.scope-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--light-green);
  font-weight: bold;
}

.how-it-works {
  padding: 5rem 2rem;
  background: linear-gradient(to bottom, var(--bg-light), var(--white));
}

.steps-container {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.step-item {
  background: var(--white);
  padding: 2rem;
  border-radius: 12px;
  box-shadow: 0 4px 15px var(--shadow);
  flex: 1;
  min-width: 250px;
  max-width: 300px;
  text-align: center;
}

.step-number {
  background: var(--primary-green);
  color: var(--white);
  width: 60px;
  height: 60px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 1.5rem;
  font-size: 1.2rem;
  font-weight: bold;
}

.step-item h3 {
  color: var(--accent-green);
  margin-bottom: 1rem;
  font-size: 1.2rem;
}

.step-arrow {
  font-size: 2rem;
  color: var(--primary-green);
  font-weight: bold;
}

.comparison-table {
  padding: 5rem 2rem;
  background: var(--bg-light);
}

.table-intro, .table-note {
  text-align: center;
  color: var(--text-gray);
  margin-bottom: 2rem;
  line-height: 1.8;
}

.table-note {
  margin-top: 2rem;
  font-size: 0.95rem;
}

.comparison-grid {
  width: 100%;
  border-collapse: collapse;
  background: var(--white);
  box-shadow: 0 4px 15px var(--shadow);
  border-radius: 10px;
  overflow: hidden;
}

.comparison-grid thead {
  background: var(--primary-green);
  color: var(--white);
}

.comparison-grid th, .comparison-grid td {
  padding: 1.2rem;
  text-align: left;
  border-bottom: 1px solid #e2e8f0;
}

.comparison-grid th {
  font-weight: 600;
  font-size: 1.1rem;
}

.comparison-grid tbody tr:hover {
  background: var(--bg-light);
}

.comparison-grid td:nth-child(2) {
  color: var(--accent-green);
  font-weight: 600;
}

.why-choose {
  padding: 5rem 2rem;
  background: var(--white);
}

.reasons-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
}

.reason-box {
  background: linear-gradient(135deg, var(--primary-green), var(--accent-green));
  color: var(--white);
  padding: 2.5rem;
  border-radius: 12px;
  box-shadow: 0 6px 20px var(--shadow);
  transition: transform 0.3s;
}

.reason-box:hover {
  transform: translateY(-8px);
}

.reason-box h3 {
  font-size: 1.4rem;
  margin-bottom: 1rem;
  color: var(--gold);
}

.usage-guide {
  padding: 5rem 2rem;
  background: var(--bg-light);
}

.guide-content {
  display: grid;
  gap: 2rem;
}

.guide-block {
  background: var(--white);
  padding: 2rem;
  border-radius: 10px;
  box-shadow: 0 3px 10px var(--shadow);
  border-top: 4px solid var(--accent-green);
}

.guide-block h3 {
  color: var(--primary-green);
  font-size: 1.4rem;
  margin-bottom: 1.2rem;
}

.guide-block p {
  color: var(--text-gray);
  margin-bottom: 1rem;
}

.faq-section {
  padding: 5rem 2rem;
  background: var(--white);
}

.faq-list {
  max-width: 900px;
  margin: 0 auto;
}

.faq-item {
  background: var(--bg-light);
  margin-bottom: 1rem;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 8px var(--shadow);
}

.faq-item summary {
  padding: 1.5rem;
  font-weight: 600;
  color: var(--primary-green);
  cursor: pointer;
  font-size: 1.1rem;
  transition: background 0.3s;
}

.faq-item summary:hover {
  background: var(--white);
}

.faq-item p {
  padding: 0 1.5rem 1.5rem;
  color: var(--text-gray);
  line-height: 1.8;
}

.detection-demo {
  padding: 5rem 2rem;
  background: var(--white);
}

.demo-showcase {
  max-width: 900px;
  margin: 0 auto;
  text-align: center;
}

.demo-showcase picture {
  display: block;
  margin-bottom: 2rem;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 6px 20px var(--shadow);
}

.demo-showcase img {
  width: 100%;
  height: auto;
  display: block;
}

.demo-caption {
  color: var(--text-gray);
  font-size: 1.05rem;
  line-height: 1.8;
  text-align: center;
}

.report-showcase {
  padding: 5rem 2rem;
  background: var(--bg-light);
}

.report-demo {
  max-width: 1000px;
  margin: 0 auto;
  text-align: center;
}

.report-demo picture {
  display: block;
  margin-bottom: 2rem;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 8px 25px var(--shadow);
}

.report-demo img {
  width: 100%;
  height: auto;
  display: block;
}

.report-desc {
  color: var(--text-gray);
  font-size: 1.05rem;
  line-height: 1.9;
  max-width: 800px;
  margin: 0 auto;
}

.partners-section {
  padding: 5rem 2rem;
  background: var(--white);
}

.partners-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 2rem;
  align-items: center;
  justify-items: center;
  margin-bottom: 2rem;
}

.partners-grid img {
  max-width: 100%;
  height: auto;
  filter: grayscale(100%);
  opacity: 0.7;
  transition: all 0.3s;
}

.partners-grid img:hover {
  filter: grayscale(0%);
  opacity: 1;
  transform: scale(1.1);
}

.partners-note {
  text-align: center;
  color: var(--text-gray);
  font-size: 1.05rem;
  line-height: 1.8;
  max-width: 800px;
  margin: 0 auto;
}

.academic-integrity {
  padding: 5rem 2rem;
  background: linear-gradient(to right, var(--bg-light), var(--white));
}

.integrity-content {
  display: grid;
  gap: 2rem;
}

.integrity-item {
  background: var(--white);
  padding: 2rem;
  border-radius: 10px;
  border-left: 5px solid var(--primary-green);
  box-shadow: 0 3px 10px var(--shadow);
}

.integrity-item h3 {
  color: var(--accent-green);
  font-size: 1.4rem;
  margin-bottom: 1rem;
}

.integrity-item p {
  color: var(--text-gray);
  line-height: 1.8;
}

.cta-section {
  padding: 5rem 2rem;
  background: linear-gradient(135deg, var(--primary-green), var(--accent-green));
  color: var(--white);
  text-align: center;
}

.cta-section h2 {
  font-size: 2.2rem;
  margin-bottom: 1.5rem;
}

.cta-section p {
  font-size: 1.1rem;
  margin-bottom: 2.5rem;
  opacity: 0.95;
}

.main-footer {
  background: var(--deep-green);
  color: var(--white);
  padding: 3rem 2rem 1.5rem;
}

.footer-content {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-section h4 {
  color: var(--gold);
  margin-bottom: 1rem;
  font-size: 1.2rem;
}

.footer-section p {
  line-height: 1.8;
  opacity: 0.9;
}

.footer-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-btn {
  background: transparent;
  color: var(--white);
  border: 1px solid rgba(255,255,255,0.3);
  padding: 0.6rem 1.2rem;
  border-radius: 20px;
  cursor: pointer;
  transition: all 0.3s;
  font-size: 0.9rem;
}

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

.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid rgba(255,255,255,0.2);
  opacity: 0.8;
}

.modal {
  display: none;
  position: fixed;
  z-index: 1000;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.9);
}

.modal-content {
  margin: auto;
  display: block;
  max-width: 90%;
  max-height: 90%;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

.modal-close {
  position: absolute;
  top: 20px;
  right: 40px;
  color: var(--white);
  font-size: 40px;
  font-weight: bold;
  cursor: pointer;
}

@media (max-width: 768px) {
  .nav-menu {
    display: none;
  }
  
  .quick-nav {
    right: 1rem;
  }
  
  .banner-content h1 {
    font-size: 2rem;
  }
  
  .cta-buttons {
    flex-direction: column;
  }
  
  .step-arrow {
    display: none;
  }
  
  .comparison-grid {
    font-size: 0.9rem;
  }
  
  .comparison-grid th, .comparison-grid td {
    padding: 0.8rem;
  }
}