CSS动态水平导航菜单填充特定宽度(表格行为)

I need to create a horizontal navigation menu with a changing number of items (this is important - I can't hard-code widths into the CSS and I don't want to calculate them with JS) that fill up to a certain width, let's say 800px.

对于表格，

<table width="800" cellspacing="0" cellpadding="0">
  <tr>
    <td>One</td>
    <td>Two</td>
    <td>Three</td>
    <td>Four</td>
    <td>Five Seven</td>
  </tr>
</table>

<style>
table td {
      padding: 5px 0;
      margin: 0;
      background: #fdd;
      border: 1px solid #f00;
      text-align: center;
    }
</style>

请注意，较长的项目会占用更多空间，我可以在不更改 CSS 中的任何内容的情况下将项目添加到 HTML 中，并且菜单项会缩小以容纳额外的项目 - 整个菜单永远不会短于或长于 800 像素.

<style>
  nav {display:table; width:800px; background:yellow}
  ul {display:table-row; }
  li {display:table-cell; border:1px solid red}
</style>

<nav>
 <ul>
  <li>One</li>
  <li>Two</li>
  <li>Three</li>
  <li>Four</li>
  <li>Five Seven</li>
 </ul>
</nav>