:root {
  --primary-color: #2563eb;
  --secondary-color: #1e40af;
  --text-color: #1f2937;
  --light-text: #6b7280;
  --bg-color: #f3f4f6;
  --white: #ffffff;
  --max-width: 1200px;
}

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

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

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

/* Navigation */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  z-index: 1000;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--primary-color);
}

.nav-links {
  display: flex;
  gap: 2rem;
  align-items: center;
}

.nav-links a {
  font-weight: 500;
  color: var(--text-color);
  transition: color 0.3s;
}

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

.btn {
  padding: 0.75rem 1.5rem;
  border-radius: 9999px;
  font-weight: 600;
  transition: all 0.3s;
  display: inline-block;
}

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

.btn-primary:hover {
  background-color: var(--secondary-color);
  transform: translateY(-1px);
}

/* Hero Section */
.hero {
  padding: 8rem 2rem 4rem;
  text-align: center;
  background: linear-gradient(135deg, #eff6ff 0%, #ffffff 100%);
}

.hero-content {
  max-width: 800px;
  margin: 0 auto;
}

.hero h1 {
  font-size: 3.5rem;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 1.5rem;
  background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero p {
  font-size: 1.25rem;
  color: var(--light-text);
  margin-bottom: 2.5rem;
}

/* Features */
.features {
  padding: 5rem 2rem;
  background-color: var(--white);
}

.section-title {
  text-align: center;
  font-size: 2.25rem;
  font-weight: 700;
  margin-bottom: 3rem;
}

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

.core-values-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  max-width: var(--max-width);
  margin: 0 auto;
}

@media (min-width: 768px) {
  .core-values-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.feature-card {
  padding: 2rem;
  border-radius: 1rem;
  background: var(--bg-color);
  transition: transform 0.3s;
}

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

.feature-icon {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.feature-card h3 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

/* Workflow */
.workflow {
  padding: 5rem 2rem;
  background-color: #f8fafc;
}

.steps {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 2rem;
}

.step {
  flex: 1;
  min-width: 200px;
  text-align: center;
  position: relative;
}

.step-number {
  width: 3rem;
  height: 3rem;
  background-color: var(--primary-color);
  color: var(--white);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  font-size: 1.25rem;
  margin: 0 auto 1rem;
}

/* Testimonials */
.testimonials {
  padding: 5rem 2rem;
}

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

.testimonial-card {
  padding: 2rem;
  border: 1px solid #e5e7eb;
  border-radius: 1rem;
}

.stars {
  color: #fbbf24;
  margin-bottom: 1rem;
}

/* FAQ */
.faq {
  padding: 5rem 2rem;
  background-color: #f8fafc;
}

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

.faq-item {
  margin-bottom: 1.5rem;
  background: var(--white);
  padding: 1.5rem;
  border-radius: 0.5rem;
  box-shadow: 0 1px 2px rgba(0,0,0,0.05);
}

.faq-item h4 {
  margin-bottom: 0.5rem;
  color: var(--text-color);
}

/* CTA Section */
.cta-section {
  padding: 5rem 2rem;
  text-align: center;
  background-color: var(--primary-color);
  color: var(--white);
}

.cta-section h2 {
  font-size: 2.5rem;
  margin-bottom: 1.5rem;
}

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

.cta-section .btn:hover {
  background-color: #f3f4f6;
}

/* Clients Section */
.clients {
  padding: 4rem 2rem;
  background-color: #f9fafb; /* Very light gray bg */
  text-align: center;
}

.clients-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 2rem 4rem; /* Row gap 2rem, Column gap 4rem for spacing */
  max-width: 1000px;
  margin: 0 auto;
}

.clients-grid span {
  font-size: 1.25rem;
  font-weight: 700;
  color: #d1d5db; /* Light gray text as requested */
  white-space: nowrap;
  user-select: none;
  transition: color 0.3s ease;
}

.clients-grid span:hover {
  color: #9ca3af; /* Slightly darker on hover */
}

/* Footer */
.footer {
  padding: 3rem 2rem;
  background-color: #111827;
  color: #9ca3af;
  text-align: center;
}

.footer-links {
  margin-bottom: 2rem;
  display: flex;
  justify-content: center;
  gap: 2rem;
}

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

/* Back to Top Button */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--white);
  color: #374151;
  width: 3rem;   /* 参考微信按钮尺寸 */
  height: 3rem;  /* 参考微信按钮尺寸 */
  border-radius: 50%;
  border: 1px solid #e5e7eb;
  cursor: pointer;
  box-shadow: 0 4px 6px rgba(0,0,0,0.08);
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
  z-index: 999;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 2px;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(0,0,0,0.12);
  border-color: #d1d5db;
}

.back-to-top .label {
  font-size: 10px; /* 缩小以适配 3rem 圆形 */
  color: #374151;
  line-height: 1;
}

.back-to-top svg {
  width: 16px;  /* 缩小图标 */
  height: 16px;
  display: block;
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 30px;
  height: 21px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 0;
  z-index: 1001;
}

.mobile-menu-toggle span {
  width: 100%;
  height: 3px;
  background-color: var(--primary-color);
  border-radius: 3px;
  transition: all 0.3s ease;
}


/* Responsive */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2.5rem;
  }
  
  .mobile-menu-toggle {
    display: flex;
  }

  .nav-container {
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    position: relative;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background-color: var(--white);
    flex-direction: column;
    align-items: center;
    padding: 2rem 0;
    gap: 1.5rem;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    border-top: 1px solid #e5e7eb;
  }
  
  .nav-links.active {
    display: flex;
  }
  
  .nav-links a {
    font-size: 1.1rem;
    width: 100%;
    text-align: center;
    padding: 0.5rem 0;
  }

  .clients-grid {
    gap: 1.5rem 2rem;
  }
  
  .clients-grid span {
    font-size: 1rem;
  }
}

/* New WeChat Modal Styles */
.wx-modal-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  z-index: 9999;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.wx-modal-overlay.show {
  display: flex;
  opacity: 1;
}

.wx-modal-box {
  background: #fff;
  width: 90%;
  max-width: 360px;
  border-radius: 16px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
  position: relative;
  overflow: hidden;
  transform: translateY(20px);
  transition: transform 0.3s ease;
}

.wx-modal-overlay.show .wx-modal-box {
  transform: translateY(0);
}

.wx-close-btn {
  position: absolute;
  top: 10px;
  right: 15px;
  font-size: 24px;
  color: #999;
  cursor: pointer;
  z-index: 10;
  line-height: 1;
}

.wx-header {
  padding: 24px 24px 10px;
  display: flex;
  align-items: center;
  gap: 15px;
}

.wx-avatar {
  width: 50px;
  height: 50px;
  border-radius: 8px;
  background: #eee;
  object-fit: cover;
}

.wx-info h3 {
  margin: 0;
  font-size: 16px;
  color: #333;
  font-weight: 600;
}

.wx-info p {
  margin: 4px 0 0;
  font-size: 13px;
  color: #666;
}

.wx-body {
  padding: 10px 24px 24px;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.wx-qr-wrapper {
  width: 240px;
  height: 240px;
  background-color: #fff;
  background-image: url('wechat-qr.png');
  background-size: contain;
  background-position: center;
  background-repeat: no-repeat;
  position: relative;
  margin: 10px 0;
  /* Ensure strict sizing */
  min-width: 240px;
  min-height: 240px;
}



.wx-icon-center {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 48px;
  height: 48px;
  background: #fff;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
}

.wx-footer-text {
  font-size: 13px;
  color: #888;
  margin-top: 10px;
}

/* Floating WeChat Button */
.floating-wechat-btn {
  position: fixed;
  bottom: 6rem; /* 2rem (back-to-top) + 3rem (height) + 1rem (gap) */
  right: 2rem;
  width: 3rem;
  height: 3rem;
  background: var(--white);
  border-radius: 50%; /* Make it circular like back-to-top */
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
  cursor: pointer;
  z-index: 999;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
  border: 2px solid #fff;
  overflow: hidden; /* Ensure image fits in circle */
}

.floating-wechat-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(0,0,0,0.15);
}

.floating-wechat-btn img {
  width: 70%; /* Increased width to accommodate wider icon */
  height: auto; /* Maintain aspect ratio */
  object-fit: contain;
}