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

:root {
  --primary: #1a3a5c;
  --primary-light: #264d73;
  --accent: #d4a853;
  --bg: #f5f6f8;
  --bg-section: #ffffff;
  --text: #2c3e50;
  --text-light: #5a6d7e;
  --text-on-primary: #ffffff;
  --header-bg: #1a3a5c;
  --card-bg: #ffffff;
  --card-shadow: 0 2px 12px rgba(0,0,0,0.08);
  --font-family: 'Microsoft YaHei', 'PingFang SC', sans-serif;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  opacity: 0;
  transition: opacity 0.3s ease;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

header {
  background: var(--header-bg);
  color: var(--text-on-primary);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 8px rgba(0,0,0,0.15);
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.header-logo {
  display: flex;
  flex-direction: column;
}

.logo-text {
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 1px;
}

.logo-sublink {
  font-size: 12px;
  opacity: 0.8;
}

.site-nav {
  background: var(--header-bg);
}

.nav-list {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  list-style: none;
  height: 44px;
  align-items: center;
  border-top: 1px solid rgba(255,255,255,0.1);
}

.nav-list li {
  margin-right: 32px;
}

.nav-list a {
  color: var(--text-on-primary);
  text-decoration: none;
  font-size: 15px;
  opacity: 0.85;
  transition: opacity 0.2s;
  padding: 8px 0;
}

.nav-list a:hover {
  opacity: 1;
}

.mobile-menu-btn {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.mobile-menu-btn span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text-on-primary);
  transition: transform 0.3s, opacity 0.3s;
}

.mobile-menu-btn.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

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

.mobile-menu-btn.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

.hero {
  background: var(--header-bg);
  color: var(--text-on-primary);
  padding: 60px 0;
}

.hero-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  gap: 48px;
}

.hero-center .hero-inner {
  flex-direction: column;
  text-align: center;
}

.hero-left .hero-inner {
  flex-direction: row;
  text-align: left;
}

.hero-content {
  flex: 1;
}

.hero-center .hero-content {
  max-width: 720px;
}

.hero-title {
  font-size: 42px;
  font-weight: 700;
  margin-bottom: 12px;
  letter-spacing: 2px;
}

.hero-subtitle {
  font-size: 20px;
  opacity: 0.9;
  margin-bottom: 16px;
  font-weight: 300;
}

.hero-description {
  font-size: 16px;
  opacity: 0.75;
  margin-bottom: 28px;
  line-height: 1.8;
  max-width: 600px;
}

.hero-center .hero-description {
  margin-left: auto;
  margin-right: auto;
}

.hero-btn {
  display: inline-block;
  padding: 14px 36px;
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  border-radius: 4px;
  font-size: 16px;
  font-weight: 600;
  transition: transform 0.2s, box-shadow 0.2s;
  letter-spacing: 1px;
}

.hero-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0,0,0,0.2);
}

.hero-image {
  flex: 1;
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-placeholder {
  width: 320px;
  height: 220px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-center .hero-image {
  margin-top: 20px;
}

main {
  flex: 1;
}

.section {
  padding: 60px 0;
}

.section:nth-child(odd) {
  background: var(--bg);
}

.section:nth-child(even) {
  background: var(--bg-section);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.section-title {
  text-align: center;
  font-size: 28px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 40px;
  position: relative;
  padding-bottom: 16px;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 3px;
  background: var(--primary);
  border-radius: 2px;
}

.grid {
  display: grid;
  gap: 24px;
}

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

.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

.grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

.grid-card {
  background: var(--card-bg);
  border-radius: 8px;
  padding: 28px 24px;
  box-shadow: var(--card-shadow);
  transition: transform 0.2s, box-shadow 0.2s;
  border: 1px solid rgba(0,0,0,0.04);
}

.grid-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 30px rgba(0,0,0,0.12);
}

.card-icon {
  font-size: 36px;
  margin-bottom: 16px;
}

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

.card-desc {
  font-size: 14px;
  color: var(--text-light);
  line-height: 1.7;
}

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

.about-text {
  font-size: 16px;
  color: var(--text-light);
  line-height: 2;
  margin-bottom: 16px;
  text-indent: 2em;
}

footer {
  background: var(--primary);
  color: var(--text-on-primary);
  padding: 32px 0;
  margin-top: auto;
}

.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 20px;
}

.footer-company {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 6px;
}

.footer-contact {
  font-size: 13px;
  opacity: 0.75;
}

.footer-beian {
  text-align: right;
}

.beian-link {
  color: var(--text-on-primary);
  text-decoration: none;
  font-size: 14px;
  opacity: 0.85;
  transition: opacity 0.2s;
}

.beian-link:hover {
  opacity: 1;
  text-decoration: underline;
}

.footer-copyright {
  font-size: 12px;
  opacity: 0.6;
  margin-top: 6px;
}

@media (max-width: 960px) {
  .header-inner {
    height: 56px;
  }

  .logo-text {
    font-size: 18px;
  }

  .mobile-menu-btn {
    display: flex;
  }

  .nav-list {
    display: none;
    flex-direction: column;
    height: auto;
    padding: 8px 20px;
    align-items: stretch;
  }

  .nav-list li {
    margin-right: 0;
    border-bottom: 1px solid rgba(255,255,255,0.1);
  }

  .nav-list li:last-child {
    border-bottom: none;
  }

  .nav-list a {
    display: block;
    padding: 12px 0;
  }

  .site-nav.nav-open .nav-list {
    display: flex;
  }

  .hero {
    padding: 40px 0;
  }

  .hero-inner {
    flex-direction: column;
    text-align: center;
    gap: 24px;
  }

  .hero-left .hero-inner {
    flex-direction: column;
    text-align: center;
  }

  .hero-title {
    font-size: 30px;
  }

  .hero-subtitle {
    font-size: 16px;
  }

  .hero-description {
    font-size: 14px;
  }

  .hero-placeholder {
    width: 240px;
    height: 160px;
  }

  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .section {
    padding: 40px 0;
  }

  .section-title {
    font-size: 22px;
    margin-bottom: 28px;
  }

  .footer-inner {
    flex-direction: column;
    text-align: center;
  }

  .footer-beian {
    text-align: center;
  }
}

@media (max-width: 600px) {
  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

  .hero-title {
    font-size: 26px;
  }

  .hero-btn {
    padding: 12px 28px;
    font-size: 14px;
  }

  .grid-card {
    padding: 20px 16px;
  }

  .about-text {
    font-size: 14px;
    text-indent: 1.5em;
  }
}