/* 全局重置与基础样式 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "PingFang SC", "Microsoft YaHei", sans-serif;
}

body {
  background-color: #f5f7fa;
  color: #333;
  line-height: 1.6;
}

a {
  text-decoration: none;
  color: #333;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* 头部导航 */
header {
  background-color: #fff;
  box-shadow: 0 2px 10px rgba(0,0,0,0.05);
  position: sticky;
  top: 0;
  z-index: 999;
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 80px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 24px;
  font-weight: 700;
  color: #2c3e50;
}

.logo img {
  width: 40px;
  height: 40px;
  border-radius: 8px;
}

.nav-menu {
  display: flex;
  gap: 30px;
}

.nav-menu a {
  font-size: 16px;
  font-weight: 500;
  color: #555;
  transition: color 0.3s;
}

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

/* 横幅区域 */
.banner {
  height: 400px;
  background: linear-gradient(rgba(0,0,0,0.5), rgba(0,0,0,0.5)), url("../images/banner.jpg") center center no-repeat;
  background-size: cover;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #000;
  text-align: center;
}

.banner-content h1 {
  font-size: 48px;
  margin-bottom: 20px;
  text-shadow: 0 2px 10px rgba(0,0,0,0.3);
}

.banner-content p {
  font-size: 18px;
  max-width: 600px;
  margin: 0 auto;
  opacity: 0.9;
}

/* 卡片通用样式 */
.card-section {
  padding: 60px 0;
}

.section-title {
  text-align: center;
  font-size: 32px;
  color: #2c3e50;
  margin-bottom: 40px;
  position: relative;
}

.section-title::after {
  content: "";
  display: block;
  width: 80px;
  height: 4px;
  background-color: #3498db;
  margin: 15px auto;
  border-radius: 2px;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 30px;
}

.card {
  background-color: #fff;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 5px 15px rgba(0,0,0,0.08);
  transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 25px rgba(0,0,0,0.12);
}

.card-img {
  height: 200px;
  overflow: hidden;
}

.card-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s;
}

.card:hover .card-img img {
  transform: scale(1.05);
}

.card-content {
  padding: 25px;
}

.card-title {
  font-size: 20px;
  color: #2c3e50;
  margin-bottom: 15px;
}

.card-desc {
  color: #666;
  font-size: 14px;
  margin-bottom: 20px;
  line-height: 1.7;
}

.card-btn {
  display: inline-block;
  padding: 10px 20px;
  background-color: #3498db;
  color: #fff;
  border-radius: 6px;
  font-size: 14px;
  font-weight: 500;
  transition: background-color 0.3s;
}

.card-btn:hover {
  background-color: #2980b9;
}

/* 内容页面样式 */
.content-page {
  padding: 50px 0;
  background-color: #fff;
  min-height: calc(100vh - 160px);
}

.content-container {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 20px;
}

.content-title {
  font-size: 36px;
  color: #2c3e50;
  margin-bottom: 30px;
  text-align: center;
}

.content-meta {
  text-align: center;
  color: #999;
  font-size: 14px;
  margin-bottom: 40px;
  border-bottom: 1px solid #eee;
  padding-bottom: 20px;
}

.content-body {
  font-size: 16px;
  color: #555;
  line-height: 1.8;
}

.content-body p {
  margin-bottom: 25px;
}

.content-body h3 {
  font-size: 24px;
  color: #2c3e50;
  margin: 40px 0 20px;
}

.content-body ul {
  margin-left: 20px;
  margin-bottom: 25px;
}

.content-body li {
  margin-bottom: 10px;
}

/* 底部样式 */
footer {
  background-color: #2c3e50;
  color: #fff;
  padding: 60px 0 30px;
}

.footer-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 40px;
  margin-bottom: 40px;
}

.footer-col h3 {
  font-size: 18px;
  margin-bottom: 20px;
  position: relative;
  padding-bottom: 10px;
}

.footer-col h3::after {
  content: "";
  display: block;
  width: 40px;
  height: 2px;
  background-color: #3498db;
  position: absolute;
  bottom: 0;
  left: 0;
}

.footer-col ul {
  list-style: none;
}

.footer-col ul li {
  margin-bottom: 10px;
}

.footer-col ul li a {
  color: #ddd;
  transition: color 0.3s;
}

.footer-col ul li a:hover {
  color: #3498db;
}

.copyright {
  text-align: center;
  padding-top: 30px;
  border-top: 1px solid #34495e;
  color: #bbb;
  font-size: 14px;
}

/* 响应式适配 */
@media (max-width: 768px) {
  .nav-container {
    height: auto;
    flex-direction: column;
    padding: 20px 0;
  }

  .nav-menu {
    margin-top: 20px;
    gap: 20px;
  }

  .banner {
    height: 300px;
  }

  .banner-content h1 {
    font-size: 36px;
  }

  .banner-content p {
    font-size: 16px;
  }

  .content-title {
    font-size: 28px;
  }
}