* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Microsoft YaHei", sans-serif;
}
body {
  background-color: #f5f7fa;
  color: #333;
  line-height: 1.7;
}
a {
  text-decoration: none;
  color: inherit;
}
ul {
  list-style: none;
}
.container {
  width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}
/* 导航栏 */
header {
  background: #1677ff;
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 99;
}
.nav-wrap {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 60px;
}
.logo {
  font-size: 22px;
  font-weight: bold;
}
.nav-list {
  display: flex;
  gap: 36px;
}
.nav-list li a {
  font-size: 16px;
  padding: 8px 0;
  position: relative;
}
.nav-list li a.active::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: #fff;
}
/* Banner轮播 */
.banner {
  height: 320px;
  background: linear-gradient(135deg,#0088ff,#66a3ff);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  text-align: center;
}
.banner h1 {
  font-size: 42px;
  margin-bottom: 16px;
}
.banner p {
  font-size: 18px;
  opacity: 0.9;
}
/* 通用区块 */
.section {
  padding: 60px 0;
}
.section-title {
  font-size: 26px;
  margin-bottom: 32px;
  padding-left: 12px;
  border-left: 5px solid #1677ff;
}
.card-wrap {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.card {
  background: #fff;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
  transition: 0.3s;
}
.card:hover {
  transform: translateY(-6px);
  box-shadow: 0 6px 18px rgba(22,119,255,0.15);
}
.card-img {
  height: 160px;
  background: #e8f3ff;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #1677ff;
  font-size: 20px;
}
.card-body {
  padding: 20px;
}
.card-title {
  font-size: 18px;
  margin-bottom: 10px;
  font-weight: 600;
}
.card-desc {
  color: #666;
  font-size: 14px;
}
/* 教程页双栏布局 */
.doc-wrap {
  display: flex;
  gap: 30px;
}
.doc-sidebar {
  width: 260px;
  background: #fff;
  border-radius: 8px;
  padding: 20px;
  height: fit-content;
}
.doc-sidebar h3 {
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid #eee;
}
.doc-menu li {
  padding: 8px 10px;
  margin: 6px 0;
  border-radius: 6px;
  cursor: pointer;
}
.doc-menu li:hover, .doc-menu li.active {
  background: #e8f3ff;
  color: #1677ff;
}
.doc-content {
  flex: 1;
  background: #fff;
  padding: 30px;
  border-radius: 8px;
  min-height: 600px;
}
/* 底部 */
footer {
  background: #1f2937;
  color: #aaa;
  padding: 40px 0;
  text-align: center;
  margin-top: 40px;
}
/* 移动端适配 */
@media screen and (max-width: 768px) {
  .container {
    width: 100%;
  }
  .nav-list {
    gap: 16px;
  }
  .card-wrap {
    grid-template-columns: 1fr;
  }
  .doc-wrap {
    flex-direction: column;
  }
  .doc-sidebar {
    width: 100%;
  }
}