JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    <div class="b b1">div a</div>
    <div class="right">
        <div class="b2">div b</div>
        <div class="b2">div c</div>
    </div>
</div>

CSS

.b1 {
    height: 200px;
    width: 200px;
    background: #ff0000;
}


.b, .right {
     vertical-align:top;
    display: inline-block;
}

.right{
    width: 50px;
}

.b2 {
    height: 50px;
    width: 100px;
    background: #343434;
        display: inline-block;
}
#container {
    width: 350px;
}