JSFiddle - React, Tailwind, and code Playground

HTML

<div class="diamond">
  <div class="diamond-inner">
    Test
  </div>
</div>

CSS

body {text-align:center;padding-top:30px;}

.diamond {
    width: 100px;
    height: 100px;
    position: relative;
    margin-top: 25px;
    display: inline-block;
}
.diamond:before{
    position: absolute;
    display: block;
    content: "";
    width: 100px;
    height: 100px;
    left: 0;
    top: 0;
    right: 0;
    bottom: 0;
    -webkit-transform: rotate(45deg);
    -webkit-transition: border-color 0.3s;
    -moz-transform: rotate(45deg);
    -moz-transition: border-color 0.3s;
    transform: rotate(45deg);
    box-shadow: 0px 0px 21px -2px rgba(0, 0, 0, 0.25);
}
  

.diamond-inner {
    width: 80px;
    height: 80px;
    position: relative;
    margin-top: 25px;
    display: inline-block;
}
.diamond-inner:before{
    position: absolute;
    display:block;
    content: "";
    width:80px;
    height:80px;
    left: 0;
    top: -15px;
    right: 0;
    bottom: 0;
    border: 1px solid #9C9819;
    -webkit-transform: rotate(45deg);
    -webkit-transition: border-color 0.3s;
    -moz-transform: rotate(45deg);
    -moz-transition: border-color 0.3s;
    transform: rotate(45deg);
  
}