use flex in container with multiple components

1.wrap {
2  display: flex;
3  flex-wrap: wrap;
4  flex-direction: column;         /* NEW */
5  height: 100px;                  /* NEW */
6  justify-content: space-between; /* NEW */
7}
8.elem1 {
9  width: 20%;
10  flex-basis: 100%;               /* NEW */
11  border: 1px solid red;
12}
13.elem2,
14.elem3 {
15  width: 75%;
16  flex-basis: 40%;                /* NEW */
17  border: 1px solid red;
18}