* {
  box-sizing: border-box;
}

.wrapindex {
  display: grid;
  grid-template-columns: repeat(3, 1fr);

}
.onex {
  border: 1px solid #000000;
  height: 100px;
  grid-column: 1 / 4;
  grid-row: 1;
}
.twox {
  border: 1px solid #000000;
  grid-column: 1;
  grid-row: 2;
}
.threex {
  border: 1px solid #000000;
  margin: 0 auto 0 auto;
 grid-column: 2;
  grid-row: 2;
}
.fourx {
  border: 1px solid #000000;
  grid-column: 3;
  grid-row: 2;
}