JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="box">
        <div class="i-btn">I-Btn</div>
    </div>
</div>

CSS

.container{
    height: 60px;
    width: 80%;
    border: 3px solid #333;
    margin: 20px;
    overflow: hidden;
    position: relative;
    border-radius: 10px;
    -moz-border-radius: 10px;
    -webkit-border-radius: 10px;
}
.box{
    width: 100%;
    height: 94%;
    background: #eee;
    border-radius: 10px;
    -moz-border-radius: 10px;
    -webkit-border-radius: 10px;
    position: absolute;
    left: 200px;
    border: 2px solid transparent;
    z-index: -10;
    
}

.i-btn{
    background: grey;
    height: 100%;
    width: 15%;
    border-radius: 10px;
    -moz-border-radius: 10px;
    -webkit-border-radius: 10px;
    text-align: center;
    line-height: 50px;
}