gistfile1.txt

.wrapper {
  display: flex;
  flex-wrap: wrap;
}

.wrapper {
  display: grid;
  margin: 0 auto;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  grid-auto-rows: minmax(150px, auto);
}

.panel {
  /* needed for the flex layout*/
  margin-left: 5px;
  margin-right: 5px;
  flex: 1 1 200px;
}

.tall-panel {
  grid-row-end: span 2;
}

.header,
.footer {
  margin-left: 5px;
  margin-right: 5px;
  flex: 0 1 100%;
  grid-column: 1 / -1;
}