* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
:root {
  --primary-color: #0088cc;
  --secondary-color: #2aabee;
  --dark-color: #1a1a1a;
  --light-color: #f5f5f5;
  --text-color: #333;
  --border-color: #e0e0e0;
  --success-color: #4caf50;
  --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.6;
  color: var(--text-color);
  background-color: #fff;
}
/* Header Styles */
header {
  background: linear-gradient(
    135deg,
    var(--primary-color),
    var(--secondary-color)
  );
  color: white;
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: var(--shadow);
}
nav {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 2rem;
}
.logo {
  display: flex;
  align-items: center;
  font-size: 1.5rem;
  font-weight: bold;
  text-decoration: none;
  color: white;
}
.logo img {
  margin-right: 0.5rem;
  width: 40px;
  height: 40px;
}
.nav-links {
  display: flex;
  list-style: none;
  gap: 2rem;
}
.nav-links a {
  color: white;
  text-decoration: none;
  transition: opacity 0.3s;
  font-weight: 500;
}
.nav-links a:hover {
  opacity: 0.8;
}
/* Hero Section */
.hero {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  padding: 4rem 2rem;
  text-align: center;
}
.hero-content {
  max-width: 1200px;
  margin: 0 auto;
}
.hero h1 {
  font-size: 3rem;
  margin-bottom: 1rem;
  animation: fadeInUp 0.8s ease;
}
.hero p {
  font-size: 1.3rem;
  margin-bottom: 2rem;
  opacity: 0.95;
  animation: fadeInUp 0.8s ease 0.2s backwards;
}
.cta-buttons {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  animation: fadeInUp 0.8s ease 0.4s backwards;
}
.btn {
  padding: 1rem 2rem;
  border: none;
  border-radius: 50px;
  font-size: 1.1rem;
  cursor: pointer;
  transition: all 0.3s;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 600;
}
.btn-primary {
  background: white;
  color: var(--primary-color);
}
.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 15px rgba(0, 0, 0, 0.2);
}
.btn-secondary {
  background: transparent;
  color: white;
  border: 2px solid white;
}
.btn-secondary:hover {
  background: white;
  color: var(--primary-color);
}
/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}
/* Section Styles */
section {
  padding: 4rem 2rem;
}
.section-title {
  text-align: center;
  font-size: 2.5rem;
  margin-bottom: 1rem;
  color: var(--dark-color);
}
.section-subtitle {
  text-align: center;
  font-size: 1.2rem;
  color: #666;
  margin-bottom: 3rem;
}
/* Features Section */
.features {
  background-color: var(--light-color);
}
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  max-width: 1200px;
  margin: 0 auto;
}
.feature-card {
  background: white;
  padding: 2rem;
  border-radius: 15px;
  box-shadow: var(--shadow);
  transition: transform 0.3s;
  text-align: center;
}
.feature-card:hover {
  transform: translateY(-10px);
}
.feature-icon {
  width: 80px;
  height: 80px;
  margin: 0 auto 1.5rem;
  background: linear-gradient(
    135deg,
    var(--primary-color),
    var(--secondary-color)
  );
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}
.feature-card h3 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
  color: var(--dark-color);
}
.feature-card p {
  color: #666;
  line-height: 1.8;
}
/* Download Section */
.download-section {
  background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  color: white;
}
.download-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  max-width: 1200px;
  margin: 0 auto;
}
.download-card {
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  padding: 2rem;
  border-radius: 15px;
  text-align: center;
  border: 2px solid rgba(255, 255, 255, 0.2);
  transition: all 0.3s;
}
.download-card:hover {
  background: rgba(255, 255, 255, 0.2);
  transform: scale(1.05);
}
.download-icon {
  width: 80px;
  height: 80px;
  margin: 0 auto 1rem;
  background: white;
  border-radius: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.download-card h3 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
}
.download-card .btn {
  width: 100%;
  justify-content: center;
  margin-top: 1rem;
}
/* Features Detail Section */
.features-detail {
  background: white;
}
.detail-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
  max-width: 1200px;
  margin: 0 auto;
}
.detail-item {
  display: flex;
  gap: 1.5rem;
  padding: 1.5rem;
  background: var(--light-color);
  border-radius: 10px;
  transition: all 0.3s;
}
.detail-item:hover {
  background: #e8f4f8;
  transform: translateX(10px);
}
.detail-icon {
  width: 50px;
  height: 50px;
  min-width: 50px;
  background: var(--primary-color);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.detail-content h4 {
  font-size: 1.2rem;
  margin-bottom: 0.5rem;
  color: var(--dark-color);
}
.detail-content p {
  color: #666;
  font-size: 0.95rem;
}
/* How to Install Section */
.install-guide {
  background: var(--light-color);
}
.install-steps {
  max-width: 900px;
  margin: 0 auto;
}
.step {
  background: white;
  padding: 2rem;
  margin-bottom: 2rem;
  border-radius: 15px;
  box-shadow: var(--shadow);
  display: flex;
  gap: 2rem;
  align-items: flex-start;
}
.step-number {
  width: 60px;
  height: 60px;
  min-width: 60px;
  background: linear-gradient(
    135deg,
    var(--primary-color),
    var(--secondary-color)
  );
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: bold;
}
.step-content h3 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
  color: var(--dark-color);
}
.step-content p {
  color: #666;
  line-height: 1.8;
}
/* FAQ Section */
.faq {
  background: white;
}
.faq-container {
  max-width: 900px;
  margin: 0 auto;
}
.faq-item {
  background: var(--light-color);
  margin-bottom: 1.5rem;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
}
.faq-question {
  padding: 1.5rem;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--dark-color);
  transition: background 0.3s;
}
.faq-question:hover {
  background: #e8e8e8;
}
.faq-question::after {
  content: "+";
  font-size: 1.5rem;
  color: var(--primary-color);
  transition: transform 0.3s;
}
.faq-item.active .faq-question::after {
  transform: rotate(45deg);
}
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
}
.faq-answer-content {
  padding: 0 1.5rem 1.5rem;
  color: #666;
  line-height: 1.8;
}
.faq-item.active .faq-answer {
  max-height: 500px;
}
/* Reviews Section */
.reviews {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
}
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  max-width: 1200px;
  margin: 0 auto;
}
.review-card {
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  padding: 2rem;
  border-radius: 15px;
  border: 2px solid rgba(255, 255, 255, 0.2);
}
.review-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1rem;
}
.reviewer-avatar {
  width: 60px;
  height: 60px;
  background: linear-gradient(135deg, #f093fb, #f5576c);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: bold;
}
.reviewer-info h4 {
  font-size: 1.2rem;
  margin-bottom: 0.3rem;
}
.stars {
  color: #ffd700;
  font-size: 1.1rem;
}
.review-text {
  line-height: 1.8;
  opacity: 0.95;
}
/* Comparison Section */
.comparison {
  background: var(--light-color);
}
.comparison-table {
  max-width: 1000px;
  margin: 0 auto;
  background: white;
  border-radius: 15px;
  overflow: hidden;
  box-shadow: var(--shadow);
}
.comparison-table table {
  width: 100%;
  border-collapse: collapse;
}
.comparison-table th {
  background: linear-gradient(
    135deg,
    var(--primary-color),
    var(--secondary-color)
  );
  color: white;
  padding: 1.5rem;
  text-align: left;
  font-size: 1.1rem;
}
.comparison-table td {
  padding: 1.5rem;
  border-bottom: 1px solid var(--border-color);
}
.comparison-table tr:hover {
  background: var(--light-color);
}
.check {
  color: var(--success-color);
  font-size: 1.5rem;
}
.cross {
  color: #f44336;
  font-size: 1.5rem;
}
/* Security Section */
.security {
  background: white;
}
.security-content {
  max-width: 1000px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
}
.security-image {
  width: 100%;
  height: 400px;
  background: linear-gradient(
    135deg,
    var(--primary-color),
    var(--secondary-color)
  );
  border-radius: 15px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.security-text h3 {
  font-size: 2rem;
  margin-bottom: 1rem;
  color: var(--dark-color);
}
.security-text p {
  color: #666;
  line-height: 1.8;
  margin-bottom: 1rem;
}
.security-features {
  list-style: none;
  margin-top: 2rem;
}
.security-features li {
  padding: 1rem;
  margin-bottom: 1rem;
  background: var(--light-color);
  border-radius: 10px;
  display: flex;
  align-items: center;
  gap: 1rem;
}
.security-features li::before {
  content: "🔒";
  font-size: 1.5rem;
}
/* CTA Section */
.cta-section {
  background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  color: white;
  text-align: center;
  padding: 5rem 2rem;
}
.cta-section h2 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}
.cta-section p {
  font-size: 1.3rem;
  margin-bottom: 2rem;
  opacity: 0.95;
}
/* Footer */
footer {
  background: var(--dark-color);
  color: white;
  padding: 3rem 2rem 1rem;
}
.footer-content {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  margin-bottom: 2rem;
}
.footer-section h3 {
  margin-bottom: 1rem;
  color: var(--secondary-color);
}
.footer-section ul {
  list-style: none;
}
.footer-section ul li {
  margin-bottom: 0.5rem;
}
.footer-section a {
  color: #ccc;
  text-decoration: none;
  transition: color 0.3s;
}
.footer-section a:hover {
  color: var(--secondary-color);
}
.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid #444;
  color: #999;
}
/* Animations */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}
/* Responsive Design */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2rem;
  }
  .hero p {
    font-size: 1rem;
  }
  .nav-links {
    display: none;
  }
  .section-title {
    font-size: 2rem;
  }
  .security-content {
    grid-template-columns: 1fr;
  }
  .step {
    flex-direction: column;
  }
  .comparison-table {
    overflow-x: auto;
  }
}
/* Scroll to top button */
.scroll-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 50px;
  height: 50px;
  background: var(--primary-color);
  color: white;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  display: none;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  box-shadow: var(--shadow);
  transition: all 0.3s;
  z-index: 999;
}
.scroll-top:hover {
  background: var(--secondary-color);
  transform: translateY(-5px);
}
.scroll-top.show {
  display: flex;
}