.container {
  display: grid;
  grid-template-columns: 1fr min(calc(100% - 20px), 43.75rem) 1fr;

}
.container > :not(.full-bleed) {
  grid-column: 2;
    background: mistyrose;
}
.full-bleed {
  width: 100%;
  grid-column: 1 / 4;
  border: 1px solid red;
}