.8 不支持的值</a>
    </ul>
    <li class="tocline2"><a href="syndata.html#charset" class="tocxref">4.4 CSS样式表表示（representation）</a>
    <ul class="toc">
      <li class="tocline3"><a href="syndata.html#escaping" class="tocxref">4.4.1 涉及当前字符集外的字符</a>
    </ul>
  </ul>
</div>
<h2>4.1 <a name="syntax">语法</a></h2>

<p>本节描述的语法（以及<a name="x0"><span class="index-def" title="forward-compatible parsing"><dfn>向前兼容的解析规则（forward-compa