JSFiddle - React, Tailwind, and code Playground

HTML

<div>line 1</div>
<div>line 2</div>
<div class="bigborders">line 3</div>
<div class="hidden">line 4</div>
<div class="hidden">line 5</div>
<div class="hidden">line 6</div>
<div class="bigborders">line 7</div>
<div>line 8</div>
<div>line 9</div>
<div class="bigborders">line 10</div>
<div>line 11</div>
<div>line 12</div>

CSS

div {
    border: 1px solid #AAAAAA;
    padding: 3px;
}
.hidden {
    display: none;
}
.bigborders {
    border-top: 3px solid #AAAAAA;
    border-bottom: 3px solid #AAAAAA;
}