JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    Crotte
    <div class="pouet">
        <div class="menu">ZUT</div>
    </div>
    De bique
</div>

CSS

.container {
    width:100%;
    max-width : 640px;
    min-height:250px;
    margin:auto;
    background:#cde;
}
.menu {
    width:100%;
    max-width : 640px;
    margin:auto;
    background:#dec;
}

@media (min-width: 640px) {
    .pouet:before{
        content:"yeah";
        display:block;
        position:absolute;
        width:100%;
        left:0;
        background:#edc;
        z-index:-1;
    }
}