/* ===== 基础重置 ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  font-size: 15px; line-height: 1.6; color: #1F2937;
  background: #ffffff; -webkit-font-smoothing: antialiased;
}
a { text-decoration: none; color: inherit; }
img { max-width: 100%; display: block; }

/* ===== 容器 ===== */
.container { max-width: 1100px; margin: 0 auto; padding: 0 24px; }

/* ===== 导航栏 ===== */
.site-header {
  position: fixed; top: 0; left: 0; right: 0;
  background: rgba(255,255,255,0.95); backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(0,0,0,0.06); z-index: 1000;
  transition: box-shadow 0.3s ease;
}
.site-header.scrolled { box-shadow: 0 2px 12px rgba(0,0,0,0.08); }
.header-inner {
  max-width: 1100px; margin: 0 auto; padding: 0 24px;
  height: 64px; display: flex; align-items: center; justify-content: space-between;
}
.logo { display: flex; align-items: center; gap: 10px; }
.logo img { width: 36px; height: 36px; border-radius: 8px; object-fit: contain; }
.logo-text { font-size: 18px; font-weight: 700; color: #2563EB; }

.main-nav { display: flex; gap: 28px; }
.main-nav a {
  font-size: 15px; font-weight: 500; color: #4B5563;
  position: relative; padding: 4px 0; transition: color 0.2s;
}
.main-nav a:hover { color: #2563EB; }
.main-nav a.active { color: #2563EB; font-weight: 700; }
.main-nav a::after {
  content: ''; position: absolute; bottom: 0; left: 0;
  width: 0; height: 2px; background: #2563EB; border-radius: 1px;
  transition: width 0.3s ease;
}
.main-nav a:hover::after { width: 100%; }
.main-nav a.active::after { width: 100%; }

.mobile-menu-toggle {
  display: none; width: 36px; height: 36px; border: none; background: none;
  flex-direction: column; justify-content: center; gap: 5px; cursor: pointer;
}
.mobile-menu-toggle span {
  display: block; width: 22px; height: 2px; background: #1F2937;
  border-radius: 1px; transition: all 0.3s ease;
}
.mobile-menu-toggle.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.mobile-menu-toggle.active span:nth-child(2) { opacity: 0; }
.mobile-menu-toggle.active span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

/* ===== Hero ===== */
.hero {
  position: relative; min-height: 520px;
  display: flex; align-items: center; justify-content: center;
  padding: 120px 24px 80px; overflow: hidden;
}
.hero-bg {
  position: absolute; inset: 0;
  background: linear-gradient(135deg, #2563EB 0%, #3B82F6 50%, #60A5FA 100%);
}
.hero-bg::before {
  content: ''; position: absolute; top: -80px; right: -80px;
  width: 400px; height: 400px; border-radius: 50%;
  background: rgba(255,255,255,0.08);
}
.hero-bg::after {
  content: ''; position: absolute; bottom: -60px; left: -60px;
  width: 300px; height: 300px; border-radius: 50%;
  background: rgba(255,255,255,0.05);
}
.hero-content {
  position: relative; z-index: 1; text-align: center; max-width: 640px;
}
.hero-title {
  font-size: 48px; font-weight: 800; color: white;
  line-height: 1.2; margin-bottom: 20px; letter-spacing: -0.02em;
}
.hero-desc {
  font-size: 18px; color: rgba(255,255,255,0.85);
  line-height: 1.7; margin-bottom: 32px;
}
.hero-actions { display: flex; gap: 16px; justify-content: center; }
.btn-primary {
  display: inline-flex; align-items: center; justify-content: center;
  height: 48px; padding: 0 28px; border-radius: 12px;
  background: white; color: #2563EB; font-size: 16px; font-weight: 600;
  box-shadow: 0 4px 16px rgba(0,0,0,0.12); transition: all 0.2s ease;
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 6px 20px rgba(0,0,0,0.18); }
.btn-primary:active { transform: translateY(0); }
.btn-secondary {
  display: inline-flex; align-items: center; justify-content: center;
  height: 48px; padding: 0 28px; border-radius: 12px;
  background: rgba(255,255,255,0.15); color: white; font-size: 16px; font-weight: 600;
  border: 1.5px solid rgba(255,255,255,0.3); transition: all 0.2s ease;
}
.btn-secondary:hover { background: rgba(255,255,255,0.25); }

/* ===== 通用区块 ===== */
.section-about, .section-contact { padding: 80px 0; }
.section-services { padding: 80px 0; background: #F9FAFB; }
.section-header { margin-bottom: 48px; }
.section-header.center { text-align: center; }
.section-tag {
  display: inline-block; font-size: 13px; font-weight: 600;
  color: #2563EB; letter-spacing: 0.08em; margin-bottom: 8px;
}
.section-title {
  font-size: 32px; font-weight: 700; color: #1F2937; line-height: 1.3;
}
.section-subtitle {
  font-size: 16px; color: #6B7280; margin-top: 8px;
}

/* ===== 关于我们 ===== */
.about-content { max-width: 800px; }
.about-company {
  display: flex; align-items: center; gap: 16px;
  margin-bottom: 20px; padding-bottom: 20px; border-bottom: 1px solid #F3F4F6;
}
.about-logo { width: 64px; height: 64px; border-radius: 12px; object-fit: contain; }
.about-info h3 { font-size: 20px; font-weight: 600; color: #1F2937; }
.about-en { font-size: 13px; color: #9CA3AF; margin-top: 4px; }
.about-desc {
  font-size: 16px; color: #4B5563; line-height: 1.8; margin-bottom: 24px;
}
.tag-list { display: flex; flex-wrap: wrap; gap: 10px; }
.tag {
  padding: 6px 14px; border-radius: 50px;
  background: #EFF6FF; color: #2563EB;
  font-size: 13px; font-weight: 500;
}

/* ===== 服务范围 ===== */
.services-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px;
}
.service-card {
  background: white; border-radius: 16px; padding: 32px;
  box-shadow: 0 1px 4px rgba(0,0,0,0.06);
  transition: all 0.3s ease; position: relative; overflow: hidden;
}
.service-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 32px rgba(0,0,0,0.08);
}
.service-icon {
  width: 52px; height: 52px; border-radius: 14px;
  background: linear-gradient(135deg, #2563EB, #3B82F6);
  color: white; display: flex; align-items: center; justify-content: center;
  margin-bottom: 20px;
}
.service-icon svg { width: 24px; height: 24px; }
.service-num {
  position: absolute; top: 24px; right: 24px;
  font-size: 40px; font-weight: 800; color: #F3F4F6; line-height: 1;
}
.service-title { font-size: 18px; font-weight: 600; color: #1F2937; margin-bottom: 10px; }
.service-desc { font-size: 14px; color: #6B7280; line-height: 1.7; }

/* ===== 联系我们 ===== */
.contact-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px;
}
.contact-card-item {
  background: white; border-radius: 16px; padding: 32px;
  text-align: center; box-shadow: 0 1px 4px rgba(0,0,0,0.06);
  transition: all 0.3s ease;
}
.contact-card-item:hover { transform: translateY(-4px); box-shadow: 0 12px 32px rgba(0,0,0,0.08); }
.contact-icon {
  width: 56px; height: 56px; border-radius: 16px;
  background: #EFF6FF; color: #2563EB;
  display: flex; align-items: center; justify-content: center;
  margin: 0 auto 16px;
}
.contact-icon svg { width: 24px; height: 24px; }
.contact-label { font-size: 13px; color: #9CA3AF; margin-bottom: 6px; }
.contact-value { font-size: 16px; font-weight: 600; color: #1F2937; }

/* ===== 页脚 ===== */
.site-footer {
  background: #1F2937; color: #9CA3AF; padding: 32px 0;
}
.footer-inner {
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 12px;
}
.footer-brand { display: flex; align-items: center; gap: 10px; color: white; font-weight: 600; }
.footer-logo { width: 28px; height: 28px; border-radius: 6px; object-fit: contain; }
.footer-icp { font-size: 13px; color: #6B7280; }
.footer-copy { font-size: 13px; color: #6B7280; }

/* ===== 响应式 ===== */
@media (max-width: 768px) {
  .main-nav { display: none; position: absolute; top: 64px; left: 0; right: 0;
    background: white; flex-direction: column; padding: 16px 24px;
    border-bottom: 1px solid #E5E7EB; box-shadow: 0 4px 12px rgba(0,0,0,0.08);
    gap: 0;
  }
  .main-nav.active { display: flex; }
  .main-nav a { padding: 12px 0; border-bottom: 1px solid #F3F4F6; }
  .main-nav a:last-child { border-bottom: none; }
  .main-nav a::after { display: none; }
  .mobile-menu-toggle { display: flex; }

  .hero { min-height: 420px; padding: 100px 20px 60px; }
  .hero-title { font-size: 32px; }
  .hero-desc { font-size: 16px; }
  .hero-actions { flex-direction: column; gap: 12px; }
  .btn-primary, .btn-secondary { width: 100%; }

  .section-title { font-size: 26px; }
  .services-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .footer-inner { flex-direction: column; gap: 12px; text-align: center; }
  .about-company { flex-direction: column; align-items: flex-start; }
}

@media (max-width: 480px) {
  .hero-title { font-size: 28px; }
  .section-about, .section-services, .section-contact { padding: 56px 0; }
  .section-header { margin-bottom: 32px; }
  .service-card { padding: 24px; }
  .contact-card-item { padding: 24px; }
}