/* ===== 全局重置与字体 ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  background-color: #ffffff;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: #1d1d1f;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== 苹果风格导航 (共用) ===== */
.nav {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  height: 44px;
  border-bottom: 1px solid rgba(0, 0, 0, 0.08);
}

.nav-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 44px;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.logo {
  font-size: 1.3rem;
  font-weight: 400;
  text-decoration: none;
  color: #1d1d1f;
  letter-spacing: -0.02em;
}

.logo .cas {
  color: #0066cc;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 2.5rem;
  margin: 0;
  padding: 0;
}

.nav-links a {
  text-decoration: none;
  color: #333;
  font-size: 0.9rem;
  font-weight: 400;
  transition: color 0.2s;
}

.nav-links a:hover {
  color: #1d1d1f;
}

.nav-links a.active {
  color: #1d1d1f;
  font-weight: 500;
}

.nav-right {
  width: 40px;
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.2rem;
  color: #333;
  cursor: pointer;
  padding: 0 8px;
}

.mobile-menu {
  display: none;
  background: #ffffff;
  border-top: 1px solid #f2f2f2;
  padding: 1rem 24px;
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.04);
}

.mobile-menu.show {
  display: block;
}

.mobile-menu-links {
  list-style: none;
  max-width: 1200px;
  margin: 0 auto;
}

.mobile-menu-links li {
  border-bottom: 1px solid #f2f2f2;
}

.mobile-menu-links li:last-child {
  border-bottom: none;
}

.mobile-menu-links a {
  display: block;
  padding: 0.8rem 0;
  color: #1d1d1f;
  text-decoration: none;
  font-size: 1.2rem;
  font-weight: 400;
}

.mobile-menu-links a.active {
  font-weight: 500;
  color: #0066cc;
}

@media (max-width: 768px) {
  .nav-links, .nav-right {
    display: none;
  }
  .menu-toggle {
    display: block;
  }
  .nav-content {
    justify-content: space-between;
  }
}

/* ===== 通用排版（标题大小已缩小，可在此调整）===== */
h1 {
  font-size: 1.5rem;      /* 修改此处可调整 h1 大小 */
  font-weight: 500;
  letter-spacing: -0.02em;
  margin: 1.5rem 0 0.75rem;
  line-height: 1.2;
}

h2 {
  font-size: 1.3rem;      /* 修改此处可调整 h2 大小 */
  font-weight: 500;
  letter-spacing: -0.02em;
  margin: 1.5rem 0 0.75rem;
}

h3 {
  font-size: 1.0rem;      /* 修改此处可调整 h3 大小 */
  font-weight: 500;
  margin: 1rem 0 0.5rem;
}

p, li {
  font-size: 1rem;
  font-weight: 400;
  color: #333;
}

.subhead {
  font-size: 1.1rem;
  color: #6e6e73;
  margin-bottom: 1.5rem;
}

hr {
  border: none;
  border-top: 1px solid #f2f2f2;
  margin: 2.5rem 0;
}

/* 列表样式 */
ul {
  list-style: none;
  padding-left: 0;
}

.list-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
  font-size: 1rem;
}

.list-item i {
  color: #0066cc;
  width: 1.5rem;
  text-align: center;
}

.monitor-list {
  margin: 1.5rem 0;
}

.monitor-list li {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.6rem 0;
  border-bottom: 1px solid #f2f2f2;
  font-size: 1rem;
}

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

.monitor-list i {
  color: #0066cc;
  width: 1.8rem;
  font-size: 1.2rem;
}

/* 网格布局 */
.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  margin: 2rem 0;
}

/* 按钮 */
.btn {
  display: inline-block;
  background: #0066cc;
  color: white;
  padding: 0.6rem 1.5rem;
  text-decoration: none;
  font-weight: 400;
  border: none;
  cursor: pointer;
}

.btn-outline {
  background: transparent;
  color: #0066cc;
  border: 1px solid #0066cc;
  padding: 0.5rem 1.5rem;
}

.btn-outline:hover {
  background: #0066cc;
  color: white;
}

/* 图片 */
img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* 页脚 */
.footer {
  text-align: center;
  padding: 2rem 0;
  border-top: 1px solid #f2f2f2;
  margin-top: 3rem;
}

.footer a {
  color: #6e6e73;
  text-decoration: none;
  font-size: 0.9rem;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.footer a:hover {
  color: #0066cc;
}

/* 移动端优化 */
@media (max-width: 768px) {
  h1 { font-size: 1.4rem; }   /* 移动端可再缩小 */
  h2 { font-size: 1.2rem; }
  h3 { font-size: 0.9rem; }
  p, li, .list-item, .monitor-list li { font-size: 1rem; }
  .subhead { font-size: 1rem; }
  .grid-2 { grid-template-columns: 1fr; gap: 1.5rem; }
}

/* 在文件末尾追加以下样式 */

/* 桌面端二级菜单 */
.dropdown {
  position: relative;
}

.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  background: #ffffff;
  border-radius: 8px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.1);
  padding: 0.5rem 0;
  min-width: 150px;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.2s, visibility 0.2s;
  z-index: 1000;
  margin-top: 8px;
  list-style: none;
}

.dropdown:hover .dropdown-menu {
  opacity: 1;
  visibility: visible;
}

.dropdown-menu li {
  border-bottom: none;
}

.dropdown-menu a {
  display: block;
  padding: 0.5rem 1.5rem;
  color: #333;
  text-decoration: none;
  font-size: 0.9rem;
  white-space: nowrap;
}

.dropdown-menu a:hover {
  background: #f5f5f7;
  color: #0066cc;
}

/* 移动端二级菜单 */
.mobile-menu .has-submenu > a {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.mobile-menu .submenu-arrow {
  font-size: 1.2rem;
  transition: transform 0.2s;
}

.mobile-menu .has-submenu.open .submenu-arrow {
  transform: rotate(90deg);
}

.mobile-menu .submenu {
  display: none;
  padding-left: 1.5rem;
  list-style: none;
}

.mobile-menu .has-submenu.open .submenu {
  display: block;
}

.mobile-menu .submenu li {
  border-bottom: none;
}

.mobile-menu .submenu a {
  font-size: 1rem;
  padding: 0.6rem 0;
  color: #666;
}

.mobile-menu .submenu a:hover {
  color: #0066cc;
}