Bootstrap被识别但不起作用

Question

我正在编写我的第一个Bootstrap应用程序，标签中的类不起作用。它就像没有样式的CSS一样工作，即使我在javascript中检查启用了Bootstrap。

<div class="container-fluid">  

<div class="row-fluid">
    <div class="col-lg-6 col-sm-12 header">
        <img src="/img/spaceportLogo.png" alt="Spaceport Logo">
    </div>
</div>

<div class="row-fluid">
    <div class="col-lg-6 col-sm-12 hometext">
        <h1>REAL. SPACE.</h1>
        <p>With space available for researching, building and testing a wide range of commercial space applications, the Houston Spaceport offers unparalleled access to the tools, facilities and infrastructure you need.  Click here to learn how you can become a part of the world's first truly urban spaceport.</p>
    </div>
</div>
</div>

以下是JSFiddle