Bootstrap中的响应式断点

 

<div class="container mb-5 mt-5">
        <div class="row">
            <div class="col-sm-4">
                <div class="box"></div>
            </div>
            <div class="col-sm-4">
                <div class="box"></div>
            </div>
            <div class="col-sm-4">
                <div class="box"></div>
            </div>
        </div>
    </div>
    <div class="container mb-5 mt-5">
        <div class="row">
            <div class="col-md-3">
                <div class="box"></div>
            </div>
            <div class="col-md-3">
                <div class="box"></div>
            </div>
            <div class="col-md-3">
                <div class="box"></div>
            </div>
            <div class="col-md-3">
                <div class="box"></div>
            </div>
        </div>
    </div>

 

 

 

 

 

 

 

 

可以设置多个断点