JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="leftMenu">LeftMenu</div>
    <div class="RightContainer">
        <div class="top">top</div>
        <div class="columns">
            <div class="c1">left</div>
            <div class="c2">centre</div>
            <div class="c3">right</div>
        </div>
        <div class="main">Main content</div>
    </div>
</div>

CSS

div {
    margin: 0px;
    padding: 0px;
    border: 0px;
}

.container {
    height: 500px;
}

.leftMenu {
    float: left;
    height: 100%;
    width: 75px;
    background-color: #999;
}

.RightContainer {
    height: 100%;
    float: left;
    width: 500px;
    background-color: #333;
}

.columns {
    width: 100%;
    height: 300px;
    background-color: #D0D;
}
.c1, .c2, .c3 {
    height: 100%;
    width: 32%;
    background-color: #0DD;
}
.main {
    background-color: #F00;
    height: auto;
}