/*
 * 顶栏导航样式（header.css）
 * 适用页面：所有引入 common/header.html 的页面
 * 内容：毛玻璃吸顶 header、Logo、中间文章分类导航、右侧用户区
 * 说明：白色科技风，header 白色毛玻璃 + 浅灰边框，文字深灰。
 */
.nav-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255,255,255,.82);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid rgba(100,116,139,.14);
}

.header-inner {
  max-width: 1200px; margin: 0 auto; padding: 0 24px;
  display: flex; align-items: center; justify-content: space-between; gap: 16px; height: 64px;
}

.logo { display: flex; align-items: center; gap: 12px; flex-shrink: 0; }

.logo-icon {
  width: 40px; height: 40px; display: flex; align-items: center; justify-content: center;
  border-radius: 12px; color: #fff; font-size: 22px;
  background: linear-gradient(135deg, #3b82f6, #22d3ee);
  box-shadow: 0 4px 16px rgba(59,130,246,.4);
}

.logo-text { font-size: 20px; font-weight: 700; color: #0f172a; letter-spacing: .5px; }

.header-cats {
  flex: 1; min-width: 0; display: flex; align-items: center; gap: 4px;
  overflow-x: auto; padding: 0 8px;
  scrollbar-width: none;
}
.header-cats::-webkit-scrollbar { display: none; }

.cat-link {
  color: #64748b; font-size: 14px; padding: 5px 12px; border-radius: 8px;
  white-space: nowrap; transition: color .2s, background .2s; flex-shrink: 0;
}
.cat-link:hover { color: #3b82f6; background: rgba(59,130,246,.08); }
.cat-link.active { color: #2563eb; background: rgba(59,130,246,.12); font-weight: 600; }

.nav-right { display: flex; align-items: center; gap: 18px; flex-shrink: 0; }

.nav-link { color: #475569; font-size: 14px; transition: color .2s; }
.nav-link:hover { color: #2563eb; }

.nav-btn {
  padding: 7px 18px; border-radius: 8px; color: #fff;
  background: linear-gradient(135deg, #3b82f6, #22d3ee);
  box-shadow: 0 4px 14px rgba(59,130,246,.3);
}
.nav-btn:hover { color: #fff; opacity: .9; }