How to make indents between columns in a responsive website?

Question

css

Hello. Can you please tell me the best way to make indents between columns along the Y axis in an adaptive site, when, for example, a column goes to another line, so that everything is centered?

asked for then the bottom indent was large
<div class="col-3 mb-3">

<div class="container">
   <div class="card">
      <div class="card-header">Product list</div>
      <div class="card-body">
         <div class="row">
            <div class="col-3">
               <div class="card">
                  <div class="card-header">1 Iphone 1</div>
                  <div class="card-body"></div>
               </div>
            </div>
            <div class="col-3">
               <div class="card">
                  <div class="card-header">1 Iphone 2</div>
                  <div class="card-body"></div>
               </div>
            </div>
            <div class="col-3">
               <div class="card">
                  <div class="card-header">1 Iphone 3</div>
                  <div class="card-body"></div>
               </div>
            </div>
            <div class="col-3">
               <div class="card">
                  <div class="card-header">1 Iphone 4</div>
                  <div class="card-body"></div>
               </div>
            </div>
            <div class="col-3">
               <div class="card">
                  <div class="card-header">1 Iphone 5</div>
                  <div class="card-body"></div>
               </div>
            </div>
            <div class="col-3">
               <div class="card">
                  <div class="card-header">1 Iphone 6</div>
                  <div class="card-body"></div>
               </div>
            </div>
            <div class="col-3">
               <div class="card">
                  <div class="card-header">1 Iphone 7</div>
                  <div class="card-body"></div>
               </div>
            </div>
         </div>
      </div>
   </div>
</div>

Answer 1

Elementary Watson!

<div class="card-body pt-3 pb-0">
<div class="col-3 mb-3">