Bootstrap通过定义四个类名来控制文本的对齐风格：
☑ .text-left：左对齐
☑ .text-center：居中对齐
☑ .text-right：右对齐
☑ .text-justify：两端对齐
P.S.：目前两端对齐在各浏览器下解析各有不同，特别是应用于中文文本的时候。所以项目中慎用。
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>文本对齐风格</title>
<link rel="stylesheet" href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css">
</head> <body>
<p class="text-left">我居左</p>
<p class="text-center">我居中</p>
<p class="text-right">我居右</p>
<p class="text-justify">There is clearly a need for CSS to be taken seriously by graphic artists. The Zen Garden aims to excite, inspire, and encourage participation. To begin, view some of the existing designs in the list. Clicking on any one will load the style sheet into this very page. The code remains the same, the only thing that has changed is the external .css file. </p> </body>
</html>