JSFiddle - React, Tailwind, and code Playground

HTML

<div class="shadow">
    <div class="float">
    </div>
    <div class="block"></div>
</div>

CSS

.shadow {
  width: 300px;   
  background: pink;
    height: 200px;
    padding:6px 2px 2px 6px;//
     -webkit-box-shadow: inset 2px 2px 4px 5px #aaa; /* Saf3-4, iOS 4.0.2 - 4.2, Android 2.3+ */
     -moz-box-shadow: inset 2px 2px 4px 5px #aaa; /* FF3.5 - 3.6 */
          box-shadow: inset 2px 2px 4px 5px #aaa; /* Opera 10.5, IE9, FF4+, Chrome 6+, iOS 5 */
}

.float {
    background: yellow;
    width: 100px;
    height: 100px;
}

.block {
  height: 20px;
  background: red;    
}