/* ====== 全局样式 ====== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.6;
  color: #333;
}

/* ====== Header & Nav ====== */
header {
  background: #fff;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
  position: fixed;
  width: 100%;
  top: 0;
  z-index: 1000;
}

nav {
  max-width: 1400px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.2rem 3rem;
}

.logo {
  font-size: 1.8rem;
  font-weight: 700;
  color: #2c3e50;
  letter-spacing: 2px;
  text-decoration: none;
}

.nav-links {
  display: flex;
  gap: 2.5rem;
  list-style: none;
}

.nav-links a {
  text-decoration: none;
  color: #555;
  font-weight: 500;
  font-size: 0.95rem;
  transition: color 0.3s;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.nav-links a:hover,
.nav-links a.active {
  color: #3498db;
}

/* ====== 页面头部背景 ====== */
.home-hero, .product-header, .solution-header, .contact-header {
  margin-top: 80px;
  height: 850px;
  background-size: cover;
  background-position: center;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  text-align: center;
  flex-direction: column;
  padding: 2rem;
}

.home-hero { background: linear-gradient(rgba(0,0,0,0.3), rgba(0,0,0,0.3)), url('image1.png'); }
.product-header { background: linear-gradient(rgba(0,0,0,0.3), rgba(0,0,0,0.3)), url('image2.png'); }
.solution-header { background: linear-gradient(rgba(0,0,0,0.3), rgba(0,0,0,0.3)), url('image3.png'); }
.contact-header { background: linear-gradient(rgba(0,0,0,0.3), rgba(0,0,0,0.3)), url('image4.png'); }

.hero-content, .product-header-content, .solution-header-content, .contact-header-content {
  max-width: 900px;
  padding: 2rem;
}

.hero-content h1, .product-header-content h1, .solution-header-content h1, .contact-header-content h1 {
  font-size: 3rem;
  margin-bottom: 1rem;
  font-weight: 700;
  text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

.hero-content p, .product-header-content p, .solution-header-content p, .contact-header-content p {
  font-size: 1.2rem;
  opacity: 0.9;
  max-width: 800px;
}

/* ====== Section ====== */
.section {
  padding: 5rem 3rem;
  max-width: 1400px;
  margin: 0 auto;
}

.section-title {
  text-align: center;
  font-size: 2.5rem;
  margin-bottom: 1rem;
  color: #2c3e50;
  font-weight: 700;
}

.section-subtitle {
  text-align: center;
  color: #7f8c8d;
  margin-bottom: 3rem;
  font-size: 1.1rem;
}

/* ====== Cards/Grid ====== */
.cards-grid, .products-grid {
  display: grid;
  gap: 2.5rem;
}

.cards-grid { grid-template-columns: repeat(auto-fit, minmax(320px,1fr)); }
.products-grid { grid-template-columns: repeat(3, 1fr); }

.card, .product-card {
  background: #fff;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 15px rgba(0,0,0,0.08);
  transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover, .product-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.card-image, .product-image {
  width: 100%;
  height: 220px;
  background: linear-gradient(135deg, #3498db 0%, #2980b9 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3rem;
  color: white;
}

.card-content, .product-content {
  padding: 2rem;
}

/* ====== CTA Section ====== */
.cta-section {
  background: url('image5.png') no-repeat center center;
  background-size: cover;
  color: rgb(22, 86, 125);
  text-align: center;
  padding: 5rem 3rem;
  font-weight: bold;
}

.cta-section h2 { font-size: 2.2rem; margin-bottom: 1rem; }
.cta-button {
  background: rgb(255,255,255);
  color: #000;
  padding: 1rem 2.5rem;
  border: 2px solid black;
  border-radius: 50px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s;
  text-decoration: none;
  text-transform: uppercase;
  letter-spacing: 1px;
  display: inline-block;
  margin-top: 2rem;
}
.cta-button:hover { background: #ecf0f1; transform: translateY(-3px); }

/* ====== Footer ====== */
footer {
  background: #1a252f;
  color: #ecf0f1;
  padding: 4rem 3rem 2rem;
}

.footer-content { max-width: 1400px; margin: 0 auto; }

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px,1fr));
  gap: 3rem;
  margin-bottom: 3rem;
}

.footer-section h3 {
  color: #fff;
  margin-bottom: 1.5rem;
  font-size: 1.1rem;
  font-weight: 600;
  text-transform: uppercase;
}

.footer-section ul { list-style: none; }
.footer-section li { margin-bottom: 0.8rem; }
.footer-section a {
  color: #bdc3c7;
  text-decoration: none;
  font-size: 0.9rem;
  transition: color 0.3s;
}
.footer-section a:hover { color: #3498db; }
.footer-section p { color: #bdc3c7; font-size: 0.9rem; line-height: 1.8; }
.footer-logo { font-size: 1.8rem; font-weight: 700; color: #fff; margin-bottom: 1rem; }
.footer-bottom { border-top: 1px solid #2c3e50; padding-top: 2rem; text-align: center; color: #95a5a6; }

/* ====== 响应式 ====== */
@media (max-width: 992px) {
  nav { padding: 1rem 2rem; }
  .nav-links { gap: 1rem; }
  .hero-content, .product-header-content, .solution-header-content, .contact-header-content { padding: 1.5rem; }
  .cards-grid, .products-grid { grid-template-columns: repeat(auto-fit, minmax(300px,1fr)); }
}

@media (max-width: 768px) {
  .nav-links { display: none; flex-direction: column; background: #fff; position: absolute; top: 70px; right: 10px; width: 200px; padding: 1rem; border-radius: 10px; box-shadow: 0 5px 10px rgba(0,0,0,0.1); }
  .nav-links.active { display: flex; }
  .menu-toggle { cursor: pointer; color: #333; font-size: 2rem; }
  .hero-content h1, .product-header-content h1, .solution-header-content h1, .contact-header-content h1 { font-size: 2rem; }
  .hero-content p, .product-header-content p, .solution-header-content p, .contact-header-content p { font-size: 1rem; line-height: 1.6; }
  .cards-grid, .products-grid { grid-template-columns: 1fr; gap: 1.8rem; }
  .section { padding: 3rem 2rem; }
  footer, .footer-grid { text-align: center; grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
  body { font-size: 15px; }
  .cta-button { padding: 0.8rem 1.8rem; font-size: 0.9rem; }
  input, textarea { font-size: 0.9rem; }
}