flex

HTML

<aside class="aside">
  <div class="aside__item">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Aenean luctus pulvinar risus ut congue. Duis eu metus eros.
  </div>
  <div class="aside__item">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Aenean luctus pulvinar risus ut congue. Duis eu metus eros.</div>

</aside>

CSS

.aside__item {
  background-color: green;
  margin: 10px;
  color: white;
  width: 50%;
  min-height: 200px;
  padding: 50px;
  flex-direction: row;
}

.aside {
  display: flex;
  width: 100%;
}

* {
  padding: 0;
  box-sizing: border-box;
}