层叠样式表cascading style sheet 中 casscading(层叠)的含义

<h2>

            <span class="red">

                               text here is red

                               <span class="blue">text is blue here </span>

                               text here is red again

             </span>

</h2>

这也就是说，样式的选取 ，只按照离相关文字最近的东西来处理。