.container {
   display: grid;
   grid-template-columns: 40px 50px auto [col4-start] 50px 40px;
   grid-template-rows: 35px 50px 30px;

   border:1px solid #ddd;
   margin-top:10px;
}

.child {
  padding: 5px;
  background: #d4e6f1;
  margin: 5px;
}

.child-1 {
   grid-column-start: 2;
   grid-column-end: span col4-start;
   grid-row-start: 2;
   grid-row-end: span 2;
 }