aekaplan

p.example:before {
   background: #d31742;
   content: "before";
   color: #fff;
   padding: 0 0.3em;
}

p.example:after {
   background: #d31742;
   content: "after";

aekaplan

.column-example {
  float: left;
  margin-left: 3.2%;
  width: 31.2%;
}

.column-example:first-child {
  border: 1px solid #008080;
  margin-left: 0;
}

aekaplan

<div class="row">
  <div class="column-example-bad first">
    <p>Column 1</p>
  </div>
  
  <div class="column-example-bad">
    <p>Column 2</p>
  </div>
  
  <div class="column-example-bad">

aekaplan

.column-example-bad {
  float: left;
  margin-left: 3.2%;
  width: 31.2%;
}

.first {
  border: 1px solid #008080;
  margin-left: 0
}

aekaplan

<div class="row">
  <div class="column-example">
    <p>Column 1</p>
  </div>
  
  <div class="column-example">
    <p>Column 2</p>
  </div>
  
  <div class="column-example">

aekaplan

<meta name="viewport" content="width=device-width, initial-scale=1">

aekaplan

.container {
  margin: 0 auto;
  max-width: 48rem;
  width: 90%;
}

aekaplan

<div class="container">
  <!-- Your Content -->
</div>

aekaplan

*, *:before, *:after {
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
}

aekaplan

<div class="container">
  <div class="row clearfix">
    <div class="column half">
      <!-- Your Content -->
    </div>
    <div class="column half">
      <!-- Your Content -->
    </div>
  </div>