<section class="grid-container">
  <div></div>
  <div></div>
  <div></div>
  
  <div class="full-width"></div>

  <div></div>
  <div></div>
  <div></div> 
  


  
</section>

.grid-container {
  background: wheat;
  width: 100%;
  min-height: 100vh;
  display: grid;
  grid-template-columns: 200px auto 200px;
  grid-column-gap: 20px;
  grid-template-rows: 100px 300px 100px;
  grid-row-gap: 20px;  
}

section div {
  width: 100%;
  background: teal;
  margin-bottom: 10px;
}

.full-width {
  grid-column: 1 / -1;
}