JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrapper">
    <div class="container">Transparent</div>
    <div class="child">Opaque</div>
    <div class="child">Opaque</div>
    <div class="child">Opaque</div>    
</div>

CSS

body{
    background: url('http://www.abforce.somee.com/pages/assets/background.jpg');
    font-family: Calibri;
}
.wrapper {
    position: relative;
    width: 300px;
    height: 300px;
}
.container{
    position: absolute;
    left: 0;
    right: 0;
    top: 0;
    bottom: 0;
    opacity: 0.5;
    background: yellowgreen;
}
.child{
    position: absolute;
    width: 80px;
    height: 50px;
    background: silver;
    border: 1px solid white;
}

.child:nth-child(2){
    left: 20px;
    top: 83px;
}
.child:nth-child(3){
    left: 90px;
    top: 153px;
}
.child:nth-child(4){
    left: 210px;
    top: 93px;
}