CSS:
.row {
display: flex; /* equal height of the children */
}
.col {
flex: 1; /* additionally, equal width */
padding: 1em;
border: solid;
}
HTML:
<div class="row">
<div class="col">Lorem ipsum dolor sit amet, consectetur adipisicing elit.</div>
<div class="col">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Ad omnis quae expedita ipsum nobis praesentium velit animi minus amet perspiciatis laboriosam similique debitis iste ratione nemo ea at corporis aliquam.</div>
</div>