JSFiddle - React, Tailwind, and code Playground

HTML

<div class="minhold">
    <div class="container" style="background: red;">BOX 1</div>
    <div class="container" style="background: blue;">BOX 2</div>
    <div class="container" style="background: green;">BOX 3</div>
    <div class="container" style="background: pink;">BOX 4</div>
</div>

CSS

.minhold {
      z-index: 10;
    background-color: #ffffff;
    padding: 0 !important;
    border-radius: 4px;
    -moz-border-radius: 4px;
    border: 1px solid #ddd;
    margin-top: 6px;
    margin-left: 0.4%;
    -webkit-box-shadow: 0 6px 12px rgba(0,0,0,.175);
    box-shadow: 0 6px 12px rgba(0,0,0,.175);
    -moz-box-shadow: 0 6px 12px rgba(0,0,0,.175);
    background-clip: padding-box;
    opacity: 0.97;
    filter: alpha(opacity=97);
    width: 99%;
    float: left;
}

.container {
      width: calc(100% / 4);
      height: 150px;
      padding: 0;
      margin: 0;
      float: left;
    }