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

:root {
  --primary: #6366f1;
  --primary-dark: #4f46e5;
  --primary-light: #a5b4fc;
  --accent: #f59e0b;
  --text: #1e293b;
  --text-secondary: #64748b;
  --text-light: #94a3b8;
  --bg: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #f1f5f9;
  --border: #e2e8f0;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow: 0 4px 6px -1px rgba(0,0,0,0.07), 0 2px 4px -2px rgba(0,0,0,0.05);
  --shadow-lg: 0 10px 25px -5px rgba(0,0,0,0.08), 0 4px 10px -6px rgba(0,0,0,0.04);
  --shadow-xl: 0 20px 40px -10px rgba(0,0,0,0.1);
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --max-width: 1200px;
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  overflow-x: hidden;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

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

img {
  max-width: 100%;
  display: block;
}

/* ===== 导航栏 ===== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid transparent;
  transition: var(--transition);
}

.navbar.scrolled {
  border-bottom-color: var(--border);
  box-shadow: var(--shadow-sm);
}

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

.logo {
  font-size: 22px;
  font-weight: 700;
  color: var(--primary);
  letter-spacing: 1px;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 32px;
}

.nav-links a {
  font-size: 15px;
  font-weight: 500;
  color: var(--text-secondary);
  position: relative;
  padding: 6px 0;
  transition: var(--transition);
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary);
  border-radius: 1px;
  transition: var(--transition);
}

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

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 24px;
  color: var(--text);
  cursor: pointer;
  padding: 4px 8px;
}

/* ===== 移动端菜单 ===== */
.mobile-menu {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 1100;
}

.mobile-menu.open {
  display: block;
}

.mobile-menu-overlay {
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0.4);
  backdrop-filter: blur(4px);
}

.mobile-menu-panel {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  width: 280px;
  background: var(--bg);
  padding: 80px 32px 32px;
  display: flex;
  flex-direction: column;
  gap: 24px;
  box-shadow: var(--shadow-xl);
  animation: slideIn 0.3s ease;
}

@keyframes slideIn {
  from { transform: translateX(100%); }
  to { transform: translateX(0); }
}

.mobile-menu-close {
  position: absolute;
  top: 20px;
  right: 20px;
  background: none;
  border: none;
  font-size: 22px;
  color: var(--text-secondary);
  cursor: pointer;
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: var(--bg-tertiary);
}

.mobile-menu-panel a {
  font-size: 17px;
  font-weight: 500;
  color: var(--text);
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
}

/* ===== Hero 区域 ===== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 100px 20px;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 60% at 50% 30%, rgba(99,102,241,0.08) 0%, transparent 60%),
    radial-gradient(ellipse 60% 50% at 20% 70%, rgba(245,158,11,0.06) 0%, transparent 50%),
    radial-gradient(ellipse 60% 50% at 80% 60%, rgba(99,102,241,0.04) 0%, transparent 50%);
  z-index: 0;
}

.hero .container {
  position: relative;
  z-index: 1;
}

.hero-brand {
  font-size: clamp(16px, 3vw, 20px);
  color: var(--primary);
  font-weight: 500;
  letter-spacing: 2px;
  margin-bottom: 8px;
}

.hero-title {
  font-size: clamp(42px, 8vw, 72px);
  font-weight: 800;
  background: linear-gradient(135deg, var(--primary) 0%, #8b5cf6 50%, var(--primary-dark) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: 4px;
  margin-bottom: 16px;
}

.hero-subtitle {
  font-size: clamp(18px, 3vw, 24px);
  color: var(--text-secondary);
  margin-bottom: 24px;
  font-weight: 400;
}

.hero-desc {
  max-width: 640px;
  margin: 0 auto 40px;
  font-size: 15px;
  color: var(--text-light);
  line-height: 1.9;
}

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

/* ===== 按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 36px;
  border-radius: 50px;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.5px;
  transition: var(--transition);
  cursor: pointer;
  border: 2px solid transparent;
}

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

.btn-primary:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(99,102,241,0.35);
}

.btn-outline {
  border-color: var(--border);
  color: var(--text);
  background: var(--bg);
}

.btn-outline:hover {
  border-color: var(--primary);
  color: var(--primary);
  transform: translateY(-2px);
}

.btn-full {
  width: 100%;
}

/* ===== 通用节头 ===== */
.section-header {
  text-align: center;
  margin-bottom: 60px;
}

.section-tag {
  display: inline-block;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 3px;
  color: var(--primary);
  background: rgba(99,102,241,0.08);
  padding: 6px 16px;
  border-radius: 20px;
  margin-bottom: 16px;
}

.section-header h2 {
  font-size: clamp(28px, 5vw, 38px);
  font-weight: 700;
  color: var(--text);
  margin-bottom: 12px;
}

.section-desc {
  font-size: 16px;
  color: var(--text-secondary);
  max-width: 500px;
  margin: 0 auto;
}

/* ===== 公司介绍 ===== */
.intro {
  padding: 100px 0;
  background: var(--bg-secondary);
}

.intro-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.intro-card {
  background: var(--bg);
  border-radius: var(--radius);
  padding: 36px 28px;
  text-align: center;
  border: 1px solid var(--border);
  transition: var(--transition);
}

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

.intro-card h3 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--text);
}

.intro-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ===== 关于我们 ===== */
.about {
  padding: 100px 0;
}

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

.about-text p {
  font-size: 15px;
  color: var(--text-secondary);
  margin-bottom: 18px;
  line-height: 1.9;
}

.about-text p:last-child {
  margin-bottom: 0;
}

/* ===== 联系我们 ===== */
.contact {
  padding: 100px 0;
  background: var(--bg-secondary);
}

.contact-grid {
  display: flex;
  justify-content: center;
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: 24px;
  max-width: 480px;
  width: 100%;
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  background: var(--bg);
  border-radius: var(--radius);
  padding: 24px;
  border: 1px solid var(--border);
  transition: var(--transition);
}

.contact-item:hover {
  box-shadow: var(--shadow);
  border-color: transparent;
}

.contact-icon {
  font-size: 28px;
  flex-shrink: 0;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(99,102,241,0.08);
  border-radius: 12px;
}

.contact-detail h4 {
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 4px;
}

.contact-detail p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

.contact-detail a {
  color: var(--primary);
  transition: var(--transition);
}

.contact-detail a:hover {
  color: var(--primary-dark);
}

/* ===== 页脚 ===== */
.footer {
  background: #0f172a;
  color: #cbd5e1;
  padding: 60px 0 0;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  gap: 40px;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}

.footer-brand h3 {
  font-size: 22px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 8px;
  letter-spacing: 1px;
}

.footer-brand p {
  font-size: 14px;
  color: #94a3b8;
}

.footer-links {
  display: flex;
  gap: 60px;
}

.footer-col h4 {
  font-size: 14px;
  font-weight: 600;
  color: #fff;
  margin-bottom: 16px;
}

.footer-col a {
  display: block;
  font-size: 14px;
  color: #94a3b8;
  margin-bottom: 10px;
  transition: var(--transition);
}

.footer-col a:hover {
  color: var(--primary-light);
}

.footer-bottom {
  padding: 24px 0;
  text-align: center;
}

.footer-info {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 0;
  font-size: 13px;
  color: #64748b;
}

.footer-item {
  white-space: nowrap;
}

.footer-bottom p a {
  font-size: 13px;
  color: #64748b;
  transition: var(--transition);
}

.footer-bottom p a:hover {
  color: var(--primary-light);
}

.footer-sep {
  margin: 0 8px;
  color: #475569;
}

/* ===== 滚动动画 ===== */
.fade-up {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}

.delay-1 { transition-delay: 0.15s; }
.delay-2 { transition-delay: 0.3s; }
.delay-3 { transition-delay: 0.45s; }

/* ===== 响应式 ===== */
@media (max-width: 768px) {
  .nav-links {
    display: none;
  }

  .menu-toggle {
    display: block;
  }

  .hero {
    min-height: auto;
    padding: 120px 20px 80px;
  }

  .hero-title {
    font-size: 36px;
  }

  .intro {
    padding: 60px 0;
  }

  .intro-grid {
    grid-template-columns: 1fr 1fr;
    gap: 16px;
  }

  .intro-card {
    padding: 24px 20px;
  }

  .about {
    padding: 60px 0;
  }

  .contact {
    padding: 60px 0;
  }

  .footer-inner {
    flex-direction: column;
    gap: 32px;
  }

  .footer-links {
    gap: 40px;
  }
}

@media (max-width: 480px) {
  .intro-grid {
    grid-template-columns: 1fr;
  }

  .hero-btns {
    flex-direction: column;
    align-items: stretch;
  }

  .btn {
    justify-content: center;
  }
}