/* ===== 基础重置 ===== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-light: #eff6ff;
  --accent: #06b6d4;
  --text: #0f172a;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --surface: #f8fafc;
  --white: #ffffff;
  --radius: 12px;
  --radius-lg: 20px;
  --shadow: 0 4px 24px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 12px 48px rgba(15, 23, 42, 0.12);
  --transition: 0.25s ease;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--text);
  background: var(--white);
}

.container {
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 24px;
}

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

/* ===== 导航栏 ===== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--text);
}

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

.nav-links {
  display: flex;
  gap: 32px;
}

.nav-links a {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: color var(--transition);
}

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

/* ===== 英雄区 ===== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  padding: 80px 0 60px;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, #0f172a 0%, #1e3a8a 40%, #0e7490 100%);
  z-index: 0;
}

.hero-bg::before {
  content: '';
  position: absolute;
  top: -40%;
  right: -20%;
  width: 70vw;
  height: 70vw;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(37,99,235,0.3) 0%, transparent 70%);
}

.hero-bg::after {
  content: '';
  position: absolute;
  bottom: -30%;
  left: -10%;
  width: 50vw;
  height: 50vw;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(6,182,212,0.25) 0%, transparent 70%);
}

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  color: var(--white);
}

.hero-eyebrow {
  font-size: 0.95rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.65);
  margin-bottom: 16px;
}

.hero-title {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: 24px;
  background: linear-gradient(135deg, #ffffff 0%, #bae6fd 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.2rem);
  color: rgba(255,255,255,0.75);
  max-width: 560px;
  margin: 0 auto 40px;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 32px;
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 600;
  transition: all var(--transition);
  cursor: pointer;
  border: 2px solid transparent;
}

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

.btn-primary:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(37,99,235,0.4);
}

.btn-outline {
  background: transparent;
  color: var(--white);
  border-color: rgba(255,255,255,0.45);
}

.btn-outline:hover {
  background: rgba(255,255,255,0.1);
  border-color: rgba(255,255,255,0.8);
  transform: translateY(-2px);
}

.hero-scroll-hint {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  color: rgba(255,255,255,0.4);
  font-size: 1.4rem;
  animation: bounce 2s infinite;
  z-index: 1;
}

@keyframes bounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(8px); }
}

/* ===== 通用 Section ===== */
.section {
  padding: 100px 0;
}

.section-alt {
  background: var(--surface);
}

.section-header {
  text-align: center;
  max-width: 640px;
  margin: 0 auto 64px;
}

.section-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  color: var(--primary);
  background: var(--primary-light);
  padding: 4px 12px;
  border-radius: 100px;
  margin-bottom: 16px;
}

.section-title {
  font-size: clamp(1.8rem, 3vw, 2.5rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text);
  margin-bottom: 16px;
  line-height: 1.2;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-muted);
  line-height: 1.75;
}

/* ===== 关于我们卡片 ===== */
.about-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 28px;
}

.about-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 40px 36px;
  transition: all var(--transition);
  box-shadow: var(--shadow);
}

.about-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary);
}

.card-icon {
  font-size: 2.4rem;
  margin-bottom: 20px;
}

.about-card h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text);
}

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

/* ===== 服务区 ===== */
.services-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
}

.service-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 36px 30px;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}

.service-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition);
}

.service-card:hover::before {
  transform: scaleX(1);
}

.service-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.service-num {
  font-size: 2.5rem;
  font-weight: 900;
  color: var(--border);
  margin-bottom: 16px;
  line-height: 1;
  transition: color var(--transition);
}

.service-card:hover .service-num {
  color: var(--primary-light);
}

.service-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text);
}

.service-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.7;
}

/* ===== 联系我们 ===== */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 32px;
  max-width: 900px;
  margin: 0 auto;
}

.contact-item {
  text-align: center;
  padding: 40px 24px;
  background: var(--surface);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  transition: all var(--transition);
}

.contact-item:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow);
  transform: translateY(-4px);
}

.contact-icon {
  font-size: 2.2rem;
  margin-bottom: 16px;
}

.contact-item h4 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text);
}

.contact-item p {
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* ===== 页脚 ===== */
.footer {
  background: #0f172a;
  color: rgba(255,255,255,0.7);
  padding: 40px 0;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  text-align: center;
}

.footer .logo-icon {
  color: var(--accent);
}

.footer .logo-text {
  color: var(--white);
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 1.1rem;
  font-weight: 700;
}

.footer-copy {
  font-size: 0.85rem;
  color: rgba(255,255,255,0.45);
}

.footer-icp a {
  font-size: 0.85rem;
  color: rgba(255,255,255,0.5);
  transition: color var(--transition);
  padding: 6px 0;
  display: inline-block;
}

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

/* ===== 响应式 ===== */
@media (max-width: 768px) {
  .nav-links {
    gap: 20px;
  }

  .nav-links a {
    font-size: 0.85rem;
  }

  .section {
    padding: 72px 0;
  }

  .about-grid,
  .services-grid,
  .contact-grid {
    grid-template-columns: 1fr;
  }

  .hero-actions {
    flex-direction: column;
    align-items: center;
  }

  .btn {
    width: 100%;
    max-width: 280px;
  }
}

@media (max-width: 480px) {
  .nav-links {
    display: none;
  }
}