<style>
    .grid {
        display: grid;
        grid-auto-columns: minmax(50px, 100px);
        grid-auto-rows: minmax(50px, 100px);
        width: 200px;
        height: 200px;
    }

    .item {
        background-color: pink;
        width: 100%;
        height: 100%;
    }
</style>
<div class="grid"><div class="item"></div>