') and a specific size.">
<style>
#grid {
  display: grid;
  grid: 150px 100px / 200px 300px;
  margin: 1px 2px 3px 4px;
  padding: 20px 15px 10px 5px;
  border-width: 9px 3px 12px 6px;
  border-style: solid;
  width: 550px;
  height: 400px;
  position: relative;
}

#grid > div {
  position: absolute;
  width: 100%;
  height: 100%;
}

#firstItem {
  background: magenta;
  grid-column: 1 / 2;
  grid-row: 1 / 2;
}

#secondItem {
  background: cyan;
  grid-column: 2 / 3;
  grid-row: 1 / 2;
}

#thirdItem {
  ba