@media screen and (min-width: 60em) {
  article {
    max-inline-size: 40em;
    position: relative;
  }
  article > header {
    position: absolute;
    left: 20em;
  }
  article > *:not(header) {
    max-inline-size: 20em;
  }
  /*
  article {
    display: grid;
    grid-template-columns: calc(100% - 20em) 20em;
    grid-template-columns: 1fr minmax(240px, 20%);
    grid-template-rows: repeat(auto);
    grid-template-areas:
"content sidebar";
  }
  article > header {
    grid-area: sidebar;
  }
  article > *:not(header) {
    grid-area: content;
  }
  */
}