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

:root {
  --blue: #1a56db;
  --blue-dark: #1e40af;
  --blue-light: #e8effc;
  --gray-900: #111827;
  --gray-700: #374151;
  --gray-500: #6b7280;
  --gray-200: #e5e7eb;
  --gray-100: #f3f4f6;
  --gray-50: #f9fafb;
  --white: #ffffff;
  --radius: 12px;
  --max-w: 1100px;
  --transition: 0.25s ease;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 72px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--gray-700);
  background: var(--white);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}

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

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

/* ===== 导航 ===== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.header.scrolled {
  border-bottom-color: var(--gray-200);
  box-shadow: 0 1px 8px rgba(0, 0, 0, 0.06);
}

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

.logo {
  font-weight: 700;
  font-size: 20px;
  color: var(--gray-900);
  letter-spacing: 0.06em;
  display: flex;
  align-items: center;
  gap: 10px;
}

.logo::before {
  content: "";
  display: block;
  width: 7px;
  height: 7px;
  background: var(--blue);
  border-radius: 50%;
  flex-shrink: 0;
}

.nav {
  display: flex;
  gap: 4px;
}

.nav-link {
  padding: 8px 16px;
  border-radius: 8px;
  font-size: 15px;
  color: var(--gray-500);
  transition: color var(--transition), background var(--transition);
}

.nav-link:hover,
.nav-link.active {
  color: var(--blue);
  background: var(--blue-light);
}

.menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
}

.menu-toggle span {
  display: block;
  height: 2px;
  background: var(--gray-700);
  border-radius: 2px;
  transition: var(--transition);
}

.menu-toggle.active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.menu-toggle.active span:nth-child(2) {
  opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ===== Hero ===== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  background: var(--white);
  padding: 120px 0 80px;
  position: relative;
  overflow: hidden;
}

/* 点阵背景 */
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  background-image: radial-gradient(var(--gray-200) 1px, transparent 1px);
  background-size: 40px 40px;
  opacity: 0.35;
}

.hero .container {
  position: relative;
  z-index: 2;
}

.hero-brand {
  display: block;
  font-size: clamp(40px, 8vw, 72px);
  font-weight: 800;
  color: var(--gray-900);
  letter-spacing: 0.06em;
}

.hero-line {
  display: block;
  width: 48px;
  height: 2px;
  background: var(--blue);
  margin: 20px auto;
  border-radius: 1px;
  opacity: 0.5;
}

.hero-brand-en {
  display: block;
  font-size: clamp(14px, 2vw, 17px);
  font-weight: 500;
  color: var(--gray-500);
  letter-spacing: 0.2em;
}

.hero-subtitle {
  margin-top: 16px;
  font-size: clamp(18px, 3vw, 24px);
  color: var(--blue);
  font-weight: 500;
}

.hero-desc {
  margin-top: 12px;
  font-size: 16px;
  color: var(--gray-500);
  letter-spacing: 0.08em;
}

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

.section-alt {
  background: var(--gray-50);
}

.section-title {
  text-align: center;
  font-size: 28px;
  font-weight: 700;
  color: var(--gray-900);
  margin-bottom: 48px;
  position: relative;
}

.section-title::after {
  content: "";
  display: block;
  width: 40px;
  height: 3px;
  background: var(--blue);
  border-radius: 2px;
  margin: 16px auto 0;
}

/* ===== 关于我们 ===== */
.about-content {
  max-width: 800px;
  margin: 0 auto;
}

.about-content p {
  font-size: 17px;
  margin-bottom: 16px;
  color: var(--gray-700);
}

.about-content strong {
  color: var(--gray-900);
}

/* ===== 卡片（主营业务） ===== */
.cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  padding: 36px 28px;
  transition: transform var(--transition), box-shadow var(--transition);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.08);
}

.card-icon {
  color: var(--blue);
  margin-bottom: 20px;
}

.card-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--gray-900);
  margin-bottom: 10px;
}

.card-desc {
  font-size: 15px;
  color: var(--gray-500);
  line-height: 1.6;
}

/* ===== 产品卡片 ===== */
.product-card {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 48px;
  align-items: center;
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  padding: 48px;
}

.product-tag {
  display: inline-block;
  font-size: 13px;
  font-weight: 600;
  color: var(--blue);
  background: var(--blue-light);
  padding: 4px 12px;
  border-radius: 20px;
  margin-bottom: 12px;
}

.product-name {
  font-size: 28px;
  font-weight: 700;
  color: var(--gray-900);
  margin-bottom: 12px;
}

.product-desc {
  font-size: 16px;
  color: var(--gray-500);
  margin-bottom: 20px;
}

.product-features {
  list-style: none;
  margin-bottom: 28px;
}

.product-features li {
  position: relative;
  padding-left: 24px;
  margin-bottom: 8px;
  font-size: 15px;
  color: var(--gray-700);
}

.product-features li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 10px;
  height: 10px;
  background: var(--blue);
  border-radius: 50%;
  opacity: 0.3;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  background: var(--blue);
  color: var(--white);
  border-radius: 8px;
  font-size: 15px;
  font-weight: 600;
  transition: background var(--transition), transform var(--transition);
}

.btn:hover {
  background: var(--blue-dark);
  transform: translateY(-1px);
}

.product-visual {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 200px;
  height: 200px;
  background: var(--blue-light);
  border-radius: 24px;
  color: var(--blue);
}

/* ===== 联系我们 ===== */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.contact-item {
  text-align: center;
  padding: 32px 16px;
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  transition: border-color var(--transition);
}

.contact-item:hover {
  border-color: var(--blue);
}

.contact-icon {
  color: var(--blue);
  margin-bottom: 12px;
}

.contact-label {
  font-size: 13px;
  color: var(--gray-500);
  margin-bottom: 6px;
}

.contact-value {
  display: block;
  font-size: 15px;
  font-weight: 600;
  color: var(--gray-900);
  word-break: break-all;
}

a.contact-value:hover {
  color: var(--blue);
}

/* ===== 页脚 ===== */
.footer {
  background: var(--gray-900);
  color: var(--gray-500);
  text-align: center;
  padding: 32px 0;
  font-size: 14px;
}

.footer-beian {
  margin-top: 4px;
  font-size: 13px;
  opacity: 0.6;
}

/* ===== 滚动动画 ===== */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===== 响应式 ===== */
@media (max-width: 768px) {
  .section {
    padding: 72px 0;
  }

  .hero {
    padding: 100px 0 60px;
  }

  .nav {
    position: fixed;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--white);
    flex-direction: column;
    padding: 16px;
    border-bottom: 1px solid var(--gray-200);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: var(--transition);
  }

  .nav.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav-link {
    padding: 12px 16px;
    font-size: 16px;
  }

  .menu-toggle {
    display: flex;
  }

  .cards {
    grid-template-columns: 1fr;
  }

  .product-card {
    grid-template-columns: 1fr;
    padding: 28px;
    gap: 24px;
  }

  .product-visual {
    width: 120px;
    height: 120px;
    margin: 0 auto;
  }

  .product-icon-large svg {
    width: 48px;
    height: 48px;
  }

  .contact-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

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