:root { --blue: #0055aa; --nav-h: 100px; }
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: "Microsoft YaHei", sans-serif; padding-top: var(--nav-h); color: #333; background: #fff; }

/* 导航栏常驻 */
.header-fixed {
  position: fixed; top: 0; width: 100%; height: var(--nav-h);
  background: #fff; border-bottom: 3px solid var(--blue); z-index: 1000;
}
.header-container { max-width: 1100px; margin: 0 auto; height: 100%; display: flex; flex-direction: column; justify-content: center; }
.logo-area { padding: 5px 0; font-size: 24px; font-weight: bold; color: var(--blue); display: flex; justify-content: space-between; }

.nav-bar ul { display: flex; list-style: none; margin-top: 5px; }
.nav-bar ul li a {
  padding: 8px 12px; text-decoration: none; color: #333; font-size: 14px; font-weight: bold;
}
.nav-bar ul li a:hover, .nav-bar ul li a.active { color: var(--blue); border-bottom: 2px solid var(--blue); }

.lang-btn { font-size: 12px; border: 1px solid #ccc; padding: 2px 8px; cursor: pointer; background: #f9f9f9; }

/* 内容区域 */
.container { max-width: 1100px; margin: 30px auto; padding: 0 15px; min-height: 500px; }
h2 { color: var(--blue); border-left: 5px solid var(--blue); padding-left: 10px; margin-bottom: 20px; }
p { margin-bottom: 15px; line-height: 1.8; text-align: justify; }

/* 响应式 */
@media (max-width: 768px) {
  .header-fixed { height: auto; position: relative; }
  body { padding-top: 0; }
  .nav-bar ul { flex-wrap: wrap; }
  .logo-area { font-size: 18px; padding: 10px; }
}
.footer { text-align: center; padding: 30px; border-top: 1px solid #eee; font-size: 12px; color: #999; }