css - 在超大屏幕中并排放置三张背景照片

我有以下代码，用于将三张背景照片彼此相邻放置。我不知道为什么超大型飞机上什么也没显示。您能否提示我找出可能的原因？

<div class="jumbotron jumbotron-fluid" style=" margin-top: 90px; ">
    <div class="container text-sm-center p-y-3">

        <div class="col-lg-3  col-md-3 col-sm-3" style=" background: url('./assets/img/glass.jpg'); background-repeat: no-repeat; background-size:contain ">

        </div>


        <div class="col-lg-6  col-md-6 col-sm-6" style="background: url('./assets/img/mhacks.jpg'); background-repeat: no-repeat;  background-size:contain ">

        </div>


        <div class="col-lg-3  col-md-3 col-sm-3" style="background: url('./assets/img/rift.jpg'); background-repeat: no-repeat; background-size:contain ">

        </div>

    </div>
</div>

最佳答案

由于div内没有任何内容，因此，如果只需要div中的图像，则可以执行以下操作：

<div class="jumbotron jumbotron-fluid" style=" margin-top: 90px; ">
    <div class="container text-sm-center p-y-3">

        <div class="col-lg-3  col-md-3 col-sm-3">
            <img src="./assets/img/glass.jpg" class="img-responsive" style="width:100%; height:auto"/>
        </div>
        <div class="col-lg-6  col-md-6 col-sm-6">
            <img src="./assets/img/mhacks.jpg" class="img-responsive" style="width:100%; height:auto"/>
        </div>
        <div class="col-lg-3  col-md-3 col-sm-3">
            <img src="./assets/img/rift.jpg" class="img-responsive" style="width:100%; height:auto"/>
        </div>

    </div>
</div>