JSFiddle - React, Tailwind, and code Playground

HTML

<div id="cont">
    <div class="block a1 gauche">1er</div>
    <div class="block b2 droite">2eme</div>
    <div class="block c3 gauche">3eme</div>
    <div class="block d4 droite">4eme</div>
</div>

CSS

#cont{
    width:100%;
}
.block{
    width:50%;
}
.droite{
    float:right;
}
.gauche{
    float:left;
}
.a1{
    height:30px;
    background-color:#555;
}
.b2{
    height:50px;
    background-color:#aaa;
}
.c3{
    height:100px;
    background-color:#222;
    color:white;
}
.d4{
    height: 20px;
    background-color:#ddd;
}