对齐按钮组:使它们跨越整个宽度。
<div class="btn-group @(19)">
<button class="btn btn-primary">Apple</button>
<button class="btn btn-primary">Samsung</button>
<button class="btn btn-primary">Sony</button>
</div>
<div class="btn-group btn-group-justified">
<button class="btn btn-primary">Apple</button>
<button class="btn btn-primary">Samsung</button>
<button class="btn btn-primary">Sony</button>
</div>