{# Admin subnav — 管理后台三个页面共享。active 参数: "dashboard" / "papers" / "logs" #}
<nav class="admin-subnav">
  <a href="/admin/" class="admin-subnav-link {{ 'active' if active == 'dashboard' else '' }}">仪表盘</a>
  <a href="/admin/papers" class="admin-subnav-link {{ 'active' if active == 'papers' else '' }}">论文管理</a>
  <a href="/admin/logs" class="admin-subnav-link {{ 'active' if active == 'logs' else '' }}">日志</a>
  <span class="admin-subnav-spacer"></span>
  <form action="/admin/logout" method="post" class="admin-subnav-form">
    <button type="submit" class="admin-subnav-link admin-subnav-logout">退出登录</button>
  </form>
</nav>