:root {
  --brand: #2563eb;
  --brand-light: #38bdf8;
  --brand-gradient: linear-gradient(135deg, var(--brand), var(--brand-light));
  --bg: #f8fafc;
  --surface: #ffffff;
  --text: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --shadow-sm: 0 10px 25px rgba(0,0,0,0.03);
  --shadow-md: 0 20px 40px rgba(0,0,0,0.06);
  --shadow-lg: 0 25px 50px rgba(0,0,0,0.08);
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
html {
  scroll-behavior: smooth;
}
body {
  font-family: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
  background-image:
    radial-gradient(circle at 20% 50%, rgba(37,99,235,0.04) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, rgba(56,189,248,0.04) 0%, transparent 50%);
}
.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* --- 导航栏 --- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  transition: all var(--transition);
  background: #2563eb;
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  box-shadow: 0 1px 10px rgba(0,0,0,0.04);
  border-bottom: 1px solid rgba(255,255,255,0.5);
}
.navbar.scrolled {
  background: rgba(255,255,255,0.9);
  box-shadow: 0 10px 30px rgba(0,0,0,0.06);
  border-bottom-color: transparent;
}
.navbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 76px;
}
.logo-link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  font-weight: 800;
  font-size: 1.75rem;
  color: #ffffff;
  transition: transform var(--transition);
}
.logo-link:hover {
  transform: scale(1.02);
}
.logo-link svg {
  width: 38px;
  height: 38px;
  filter: drop-shadow(0 4px 8px rgba(37,99,235,0.3));
}
.logo-link span {
  background: #ffffff;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.nav-links {
  display: flex;
  align-items: center;
  gap: 2.2rem;
}
.nav-links a {
  text-decoration: none;
  color: #ffffff;
  font-weight: 500;
  font-size: 0.95rem;
  transition: color var(--transition);
  position: relative;
  padding: 0.5rem 0;
}
.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--brand);
  transition: width var(--transition);
  border-radius: 2px;
}
.nav-links a:hover {
  color: var(--brand);
}
.nav-links a:hover::after {
  width: 100%;
}
.hamburger {
  display: none;
  flex-direction: column;
  gap: 6px;
  cursor: pointer;
  padding: 8px;
}
.hamburger span {
  display: block;
  width: 26px;
  height: 3px;
  background: var(--text);
  border-radius: 10px;
  transition: all var(--transition);
}

/* --- 滚动后导航栏文字颜色修复 --- */
.navbar.scrolled .logo-link {
  color: var(--text);
}
.navbar.scrolled .logo-link span {
  background: var(--brand-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.navbar.scrolled .nav-links a {
  color: var(--text-secondary);
}
.navbar.scrolled .nav-links a:hover {
  color: var(--brand);
}
.navbar.scrolled .hamburger span {
  background: var(--text);
}

/* --- 英雄区 --- */
.hero {
  padding: 12rem 0 7rem;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  width: 600px;
  height: 600px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(37,99,235,0.12) 0%, transparent 70%);
  top: -200px;
  right: -200px;
  animation: float 8s ease-in-out infinite alternate;
}
.hero::after {
  content: '';
  position: absolute;
  width: 400px;
  height: 400px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(56,189,248,0.1) 0%, transparent 70%);
  bottom: -100px;
  left: -100px;
  animation: float 6s ease-in-out infinite alternate-reverse;
}
@keyframes float {
  0% { transform: translate(0, 0) scale(1); }
  100% { transform: translate(30px, -30px) scale(1.1); }
}
.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 5rem;
  align-items: center;
  position: relative;
  z-index: 2;
}
.hero-text h1 {
  font-size: 4rem;
  font-weight: 800;
  line-height: 1.1;
  color: var(--text);
  margin-bottom: 1.5rem;
  letter-spacing: -0.02em;
  min-height: 8rem; /* 预留空间防止布局跳动 */
}
.hero-text h1 span {
  background: var(--brand-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-text p {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: 2.5rem;
  max-width: 90%;
  line-height: 1.7;
}
.hero-visual {
  display: flex;
  justify-content: center;
  align-items: center;
}
.hero-visual img {
  width: 100%;
  max-width: 450px;
  height: auto;
  border-radius: 3rem;
  box-shadow: 0 30px 60px rgba(37,99,235,0.15);
  transition: transform var(--transition);
  background: linear-gradient(135deg, #eff6ff, #e0f2fe);
  object-fit: contain;
  padding: 1rem;
}
.hero-visual img:hover {
  transform: translateY(-8px);
  box-shadow: 0 40px 70px rgba(37,99,235,0.2);
}

/* --- 标题 --- */
.section-title {
  text-align: center;
  margin-bottom: 4.5rem;
}
.section-title h2 {
  font-size: 2.8rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 1rem;
  letter-spacing: -0.01em;
}
.section-title p {
  color: var(--text-muted);
  font-size: 1.15rem;
  max-width: 600px;
  margin: 0 auto;
}

/* --- 分类 --- */
.categories {
  padding: 2rem 0 5rem;
}
.categories-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
  justify-content: center;
}
.category-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  transition: transform var(--transition), filter var(--transition);
  padding: 0.75rem;
  border-radius: 1.5rem;
  background: transparent;
}
.category-item:hover {
  transform: translateY(-6px);
  background: rgba(37,99,235,0.03);
}
.category-item svg {
  width: 56px;
  height: 56px;
  margin-bottom: 0.7rem;
  filter: drop-shadow(0 4px 6px rgba(37,99,235,0.15));
}
.category-item span {
  font-weight: 600;
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* --- 关于 --- */
.about {
  padding: 7rem 0;
  background: var(--surface);
}
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 5rem;
  align-items: center;
}
.about-image-wrapper {
  background: linear-gradient(135deg, #eff6ff, #e0f2fe);
  border-radius: 3rem;
  padding: 2rem;
  display: flex;
  justify-content: center;
  box-shadow: var(--shadow-md);
  transition: transform var(--transition);
}
.about-image-wrapper:hover {
  transform: scale(1.02);
}
.about-image-wrapper img {
  max-width: 100%;
  height: auto;
  border-radius: 2rem;
  object-fit: contain;
  background: transparent;
}
.about-text h3 {
  font-size: 2.2rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 1.8rem;
  line-height: 1.3;
}
.about-text p {
  color: var(--text-secondary);
  margin-bottom: 1.8rem;
  font-size: 1.1rem;
  line-height: 1.7;
}
.about-text .highlight {
  font-weight: 700;
  color: var(--brand);
  background: linear-gradient(to right, rgba(37,99,235,0.1), transparent);
  padding: 0.2rem 0.5rem;
  border-radius: 0.4rem;
}

/* --- 服务 --- */
.services {
  padding: 7rem 0;
  background: var(--bg);
}
.services-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2.5rem;
}
.service-card {
  background: var(--surface);
  border-radius: 2.5rem;
  padding: 3rem 2rem;
  text-align: center;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition);
  border: 1px solid #f1f5f9;
  position: relative;
  overflow: hidden;
}
.service-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--brand-gradient);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition);
}
.service-card:hover {
  transform: translateY(-10px);
  box-shadow: var(--shadow-lg);
  border-color: #bfdbfe;
}
.service-card:hover::before {
  transform: scaleX(1);
}
.service-icon {
  width: 74px;
  height: 74px;
  margin: 0 auto 1.8rem;
  background: linear-gradient(135deg, #eff6ff, #e0f2fe);
  border-radius: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform var(--transition);
}
.service-card:hover .service-icon {
  transform: rotateY(10deg) scale(1.05);
}
.service-icon svg {
  width: 40px;
  height: 40px;
  stroke: var(--brand);
  fill: none;
  stroke-width: 2;
}
.service-card h4 {
  font-size: 1.4rem;
  margin-bottom: 1rem;
  color: var(--text);
}
.service-card p {
  color: var(--text-muted);
  line-height: 1.6;
}

/* --- 入驻 --- */
.join {
  padding: 7rem 0;
  background: var(--surface);
}
.steps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 3rem;
  text-align: center;
}
.step-item {
  position: relative;
}
.step-number {
  width: 70px;
  height: 70px;
  border-radius: 1.5rem;
  background: var(--brand-gradient);
  color: white;
  font-size: 2rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 1.8rem;
  box-shadow: 0 12px 28px rgba(37,99,235,0.35);
  transition: transform var(--transition);
}
.step-item:hover .step-number {
  transform: scale(1.1) rotate(5deg);
}
.step-item h4 {
  font-size: 1.25rem;
  margin-bottom: 0.6rem;
  color: var(--text);
}
.step-item p {
  color: var(--text-muted);
}
.join-cta {
  text-align: center;
  margin-top: 3.5rem;
}
.join-cta p {
  color: var(--text-muted);
  font-size: 1.1rem;
}
.join-cta strong {
  color: var(--brand);
  font-size: 1.3rem;
}

/* --- 页脚 --- */
footer {
  background: #0b1120;
  color: #cbd5e1;
  padding: 5rem 0 2rem;
}
.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 3rem;
  margin-bottom: 4rem;
}
.footer-col h4 {
  color: white;
  margin-bottom: 1.4rem;
  font-size: 1.2rem;
  font-weight: 600;
}
.footer-col p, .footer-col a {
  color: #94a3b8;
  font-size: 0.95rem;
  margin-bottom: 0.8rem;
  display: flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
  transition: color var(--transition);
}
.footer-col a:hover {
  color: var(--brand);
}
.footer-col svg {
  width: 18px;
  height: 18px;
  stroke: currentColor;
  fill: none;
  stroke-width: 2;
  flex-shrink: 0;
}
.footer-bottom {
  border-top: 1px solid #1e293b;
  padding-top: 2.5rem;
  text-align: center;
  color: #64748b;
  font-size: 0.9rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.6rem;
}
.footer-bottom a {
  color: #64748b;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  transition: color var(--transition);
}
.footer-bottom a:hover {
  color: var(--brand);
}
.footer-bottom svg {
  width: 16px;
  height: 16px;
  stroke: currentColor;
  fill: none;
  stroke-width: 2;
}

/* 隐藏 SVG 图标库 */
.hidden-svg {
  display: none;
}

/* --- 移动端适配 --- */
@media (max-width: 768px) {
  .hero-grid {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 3rem;
  }
  .hero-text p {
    max-width: 100%;
  }
  .hero-visual {
    order: -1;
  }
  .about-grid {
    grid-template-columns: 1fr;
  }
  .nav-links {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 76px;
    left: 0;
    width: 100%;
    background: rgba(255,255,255,0.98);
    backdrop-filter: blur(20px);
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    gap: 1.5rem;
  }
  .nav-links.active {
    display: flex;
  }
  .nav-links.active a {
    color: var(--text-secondary); /* 移动端菜单内链接深色 */
  }
  .nav-links.active a:hover {
    color: var(--brand);
  }
  .hamburger {
    display: flex;
  }
  .hero-visual img {
    max-width: 280px;
  }
}