JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="row">
        <div></div>
        <div></div>
        <div></div>
        <div></div>
    </div>
    <div class="row">
        <div></div>
        <div></div>
        <div></div>
        <div></div>
    </div>
    <div class="row">
        <div></div>
        <div></div>
        <div></div>
        <div></div>
    </div>
    <div class="row">
        <div></div>
        <div></div>
        <div></div>
        <div></div>
    </div>
    <div class="row">
        <div></div>
        <div></div>
        <div></div>
        <div></div>
    </div>
</div>

CSS

.container {
    width: 80%;
    height: 500px;
    margin: 30px auto;
    background: #eee;
    position: relative;
}
.container .row {
    width: 100%;
    height: 20%;
    border-top: 2px solid #aaa;
    border-bottom: 2px solid #aaa;
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
}
.container .row:first-child {
    border-top: none;
}
.container .row:last-child {
    border-bottom: none;
}
.container .row div {
    float: left;
    width: 25%;
    height: 100%;
    border-left: 2px solid #aaa;
    border-right: 2px solid #aaa;
    margin: 0; padding: 0;
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
}
.container .row div:first-child {
    border-left: none;
}
.container .row div:last-child {
    border-right: none;
}