Bootstrap 4 - 列网格无法响应

Question

I am trying to achieve bootstrap 4 column. But this is not working responsive div's are overlapping each other.

How to get achieve this responsively

this is what I have tried but it is not working responsively

<div class="container">
<div class="row">
<div class="col-md-12">
<div class="col-md-3 height"></div>
<div class="col-md-3 height"></div>
<div class="col-md-3 height"></div>
<div class="col-md-3 height"></div>
</div>
</div>
</div>

this is my css

.height{

height:350px;
}

Answer 1

you can add all column divs "col-sm-6" and "col-xs-12" if you want to work full reposive.