Instead of using an actual border around grid items, use the background color on the container (for “border” color) and the grid-gap
property (for “border” width).
.wrapper {
display: inline-grid;
grid-template-columns: 50px 50px 50px 50px;
border: 1px solid black;
grid-gap: 1px;
background-color: black;
}
.wrapper > div {
background-color: white;
padding: 15px;
text-align: center;
}
<div class="wrapper">
<div>1</div>
<div>2</div>
<div>3</div>
<div>4</div>
<div>5</div>
<div>6</div>
<div>7</div>
<div>8</div>
</div>