Bootstrap如何定位?

Bootstrap how to positioning ?

如何定位 col-md-4 - 在 col-md-12 的底部?

( post 图片 ) image

------------col-md-12----------------

(空space)

---col-md-4--- / ---col-md-4--- / ---col-md-4---

------------结束 col-md-12---------------------

<div class="container-fluid">
<div class="row">
    <div class="col-md-12 hero">
        <img src="http:/placehold.it/1600x800" alt="" class="img-responsive">
        <div class="col-md-4">
            <img src="http://placehold.it/400x300" alt="" class="img-responsive">
        </div>
        <div class="col-md-4">
            <img src="http://placehold.it/400x300" alt="" class="img-responsive">
        </div>
                <div class="col-md-4">
            <img src="http://placehold.it/400x300" alt="" class="img-responsive">
        </div>
    </div>    
</div>

<div class="container-fluid">
<div class="row">
    <div class="col-md-12 hero">
        <img src="http:/placehold.it/1600x800" alt="" class="img-responsive">
        <div class="row" id="pseudo-box">
             <div class="col-md-4">
                  <img src="http://placehold.it/400x300" alt="" class="img-responsive">
             </div>
             <div class="col-md-4">
                  <img src="http://placehold.it/400x300" alt="" class="img-responsive">
             </div>
             <div class="col-md-4">
                  <img src="http://placehold.it/400x300" alt="" class="img-responsive">
             </div>
        </div>
    </div>    
</div>

应用 #pseudo-box 并根据您的方便将其放置在父 div 中。