JSFiddle - React, Tailwind, and code Playground

HTML

<div class="backgroundG">
        <div class="section">section1</div>
        <div class="section FillUp90">section2</div>
    </div>    
    <div class="backgroundG">
        <div class="section">section3</div>
        <div class="section FillUp80">section4</div>
        <div class="section">section5</div>
    </div>

CSS

.backgroundG {
    width:100%;
    background-color:#ECECEC;
    overflow:hidden;
}


.section{
    float:left;
    height:44px;
    overflow:hidden;
    width:10%;
}

.FillUp90{  
    width:90%;
}

.FillUp80{  
    width:80%;
}