<style>
    .container {
        display: grid;
        grid-template-columns: auto 0 minmax(0, calc(100%));
        background-color: red;
    }

    .item-left {
        grid-column: 1;
        width: 100px;
        background-color: blueviolet;
    }

    .item-right {
        grid-column: 2 / span 2;
    }
</style>
<div class="container">
    <div class="item-left"></div>
    <div class="item-right">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut iaculis venenatis purus, eget blandit velit venenatis at.</div>
</div>