JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrap">
    <div class="a1"></div>
    <div class="a2"></div>
    <div class="a3"></div>
</div>

CSS

.wrap {
    background-color: #000000;
    width: 100%;  
}

.a1 {
height: 40px;
    width: 40px;
    background-color: #ff0000;
    float: left;
}

.a2 {
height: 100px;
    width: 40px;
    background-color: #00ff00;
    float: right;
}

.a3 {
height: 100px;
    width: 40px;
    background-color: #0000ff;
    float: right;
}