JSFiddle - React, Tailwind, and code Playground

HTML

<div class="columns">
    <div class="post lastpost"></div>
    <div class="post"></div>
    <div class="post"></div>
    <div class="post"></div>
    <div class="post"></div>
    <div class="post"></div>
    <div class="post"></div>
    <div class="post"></div>
    <div class="post"></div>
</div>

CSS

.columns {
    width: 100%;
}

.lastpost {
    width: 48% !important;
}

.post {
    margin: 0 1%;
    width: 23%;
    height: 150px;
    background-color: #ccc;
    margin-bottom: 15px;
    float: left;
    box-sizing:border-box;
}