/* 样式重置：SEO友好，消除浏览器差异，提升渲染速度 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Microsoft YaHei", Arial, sans-serif; /* 企业级常用字体，高可读性 */
}
html {
  scroll-behavior: smooth; /* 平滑滚动，提升体验，SEO友好 */
  font-size: 16px;
}
body {
  color: #333;
  background: #fff;
  line-height: 1.6; /* 行高优化，提升内容可读性，SEO加分 */
}
a {
  color: #0066cc; /* 企业级链接色，清晰易识别 */
  text-decoration: none;
  transition: all 0.3s ease;
}
a:hover {
  color: #004999;
  text-decoration: underline;
}
ul, ol {
  list-style: none;
}
img {
  max-width: 100%;
  height: auto;
  display: block; /* 消除图片默认间隙 */
}
button {
  border: none;
  outline: none;
  cursor: pointer;
  transition: all 0.3s ease;
}
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}
/* 隐藏元素：SEO友好（仅搜索引擎可见，不影响视觉） */
.seo-hide {
  position: absolute;
  top: -9999px;
  left: -9999px;
  width: 1px;
  height: 1px;
  overflow: hidden;
}

/* 通用模块：按钮（下载按钮突出） */
.btn {
  display: inline-block;
  padding: 12px 32px;
  border-radius: 4px;
  font-size: 18px;
  font-weight: 700;
  text-align: center;
  white-space: nowrap;
  cursor: pointer;
}
.btn-primary {
  background: #0066cc;
  color: #fff;
}
.btn-primary:hover {
  background: #004999;
  text-decoration: none;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 102, 204, 0.3);
}
.btn-secondary {
  background: #f5f7fa;
  color: #0066cc;
  border: 1px solid #0066cc;
  margin-left: 16px;
}
.btn-secondary:hover {
  background: #eef4fc;
  text-decoration: none;
}
/* 响应式按钮 */
@media (max-width: 768px) {
  .btn {
    padding: 10px 24px;
    font-size: 16px;
  }
  .btn-secondary {
    margin-left: 0;
    margin-top: 12px;
    display: block;
    width: 100%;
  }
}

/* 头部/导航：吸顶效果，企业级布局，响应式 */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: #fff;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  z-index: 999;
  padding: 16px 0;
}
.header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.logo {
  width: 120px;
}
/* 桌面端导航 */
.nav-list {
  display: flex;
  gap: 32px;
}
.nav-link {
  font-size: 16px;
  font-weight: 500;
  color: #333;
}
.nav-link.active, .nav-link:hover {
  color: #0066cc;
  text-decoration: none;
}
/* 移动端导航开关 */
.nav-toggle {
  display: none;
  font-size: 24px;
  color: #333;
  cursor: pointer;
}
/* 响应式导航：移动端隐藏，点击展开 */
@media (max-width: 768px) {
  .nav-toggle {
    display: block;
  }
  .nav-list {
    position: fixed;
    top: 80px;
    left: -100%;
    width: 100%;
    height: calc(100vh - 80px);
    background: #fff;
    flex-direction: column;
    gap: 24px;
    padding: 32px 20px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    transition: left 0.3s ease;
  }
  .nav-list.show {
    left: 0;
  }
  .nav-link {
    font-size: 18px;
  }
}

/* 主内容区通用样式：顶部留白（避免被固定导航遮挡） */
.main {
  margin-top: 96px;
  padding: 60px 0;
}
/* 模块标题：H1-H3层级规范，SEO友好 */
.h1-title {
  font-size: 36px;
  color: #333;
  text-align: center;
  margin-bottom: 16px;
  font-weight: 700;
}
.h2-title {
  font-size: 28px;
  color: #333;
  margin-bottom: 24px;
  padding-bottom: 12px;
  border-bottom: 2px solid #0066cc;
  display: inline-block;
}
.h3-title {
  font-size: 22px;
  color: #333;
  margin-bottom: 16px;
}
/* 响应式标题 */
@media (max-width: 768px) {
  .h1-title {
    font-size: 28px;
  }
  .h2-title {
    font-size: 24px;
  }
  .h3-title {
    font-size: 20px;
  }
  .main {
    padding: 40px 0;
  }
}
/* 描述文本通用样式 */
.desc-text {
  font-size: 16px;
  color: #666;
  line-height: 1.8;
  margin-bottom: 24px;
  text-align: center;
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
}

.download-section {
  background: url("../images/download-bg.webp") no-repeat center center / cover;
  background-color: rgba(245, 247, 250, 0.95);
  background-blend-mode: overlay;
  padding: 80px 0;
  margin: 40px 0;
  border-radius: 8px;
  /* backdrop-filter: blur(3px); */
}

/* 新闻展示模块：主页+新闻页，带图片，SEO友好 */
.news-section {
  padding: 40px 0;
}
.news-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 24px;
  margin-top: 32px;
}
.news-card {
  border: 1px solid #eee;
  border-radius: 8px;
  overflow: hidden;
  transition: box-shadow 0.3s ease;
}
.news-card:hover {
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
}
.news-img {
  width: 100%;
  height: 180px;
  object-fit: cover;
}
.news-content {
  padding: 20px;
}
.news-date {
  font-size: 14px;
  color: #999;
  margin-bottom: 8px;
}
.news-title {
  font-size: 18px;
  color: #333;
  margin-bottom: 12px;
  font-weight: 600;
  line-height: 1.4;
}
.news-desc {
  font-size: 14px;
  color: #666;
  line-height: 1.6;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
/* 响应式新闻 */
@media (max-width: 768px) {
  .news-list {
    grid-template-columns: 1fr;
  }
  .news-img {
    height: 160px;
  }
}

/* 内容页通用样式：教程/帮助/关于，结构化布局 */
.content-page {
  max-width: 900px;
  margin: 0 auto;
  padding: 20px 0;
}
.content-page .content-item {
  margin-bottom: 40px;
}
.content-page .content-item p {
  font-size: 16px;
  color: #666;
  line-height: 1.8;
  margin-bottom: 16px;
}
.content-page .content-item ul {
  margin-left: 24px;
  list-style: disc;
  color: #666;
  line-height: 1.8;
  margin-bottom: 16px;
}

/* 回到顶部：固定定位，滚动显示 */
.back-to-top {
  position: fixed;
  bottom: 40px;
  right: 40px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: #0066cc;
  color: #fff;
  text-align: center;
  line-height: 48px;
  font-size: 20px;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
  z-index: 998;
}
.back-to-top.show {
  opacity: 1;
  visibility: visible;
}
/* 响应式回到顶部 */
@media (max-width: 768px) {
  .back-to-top {
    width: 40px;
    height: 40px;
    line-height: 40px;
    bottom: 20px;
    right: 20px;
  }
}

/* 页脚：企业级信息，SEO内链，版权声明 */
.footer {
  background: #333;
  color: #ccc;
  padding: 60px 0 20px;
  margin-top: 40px;
}
.footer .container {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 32px;
  margin-bottom: 40px;
}
.footer-col h3 {
  font-size: 18px;
  color: #fff;
  margin-bottom: 24px;
  font-weight: 600;
}
.footer-col ul li {
  margin-bottom: 12px;
}
.footer-col ul li a {
  color: #ccc;
}
.footer-col ul li a:hover {
  color: #0066cc;
  text-decoration: none;
}
.footer-copyright {
  text-align: center;
  padding-top: 20px;
  border-top: 1px solid #444;
  font-size: 14px;
}
/* 响应式页脚 */
@media (max-width: 768px) {
  .footer .container {
    grid-template-columns: 1fr;
    gap: 24px;
  }
  .footer {
    padding: 40px 0 20px;
  }
}

/* 面包屑导航：SEO友好，提升页面层级识别 */
.breadcrumb {
  font-size: 14px;
  color: #999;
  margin-bottom: 24px;
}
.breadcrumb a {
  color: #0066cc;
}
.breadcrumb a:hover {
  text-decoration: underline;
}
.breadcrumb span {
  margin: 0 8px;
}