<style>
    * {
        border: 1px solid black;
    }

    .grid-container {
        display: grid;
        grid-template-rows: repeat(5, 20px);
    }

    .a {
        grid-row-end: span 2;
    }

    .b {
        grid-row-end: span 3;
    }
</style><div class="grid-container"><div class="a">1</div><div class="b">2</div></div>