html {
  font-family: "Open Sans", sans-serif;
}
.main {
  width: 1000px;
  height: 700px;
  margin: 0 auto;
  background:lightgray;
  display: flex;
  flex-direction:row;
  flex-wrap:wrap;
  justify-content: center;
  align-items:center;
}
.main div {
  width: 50px;
  height: 50px;
}
div div:nth-of-type(1) {
  background:lightcyan;
}
div div:nth-of-type(2) {
  background:lightcoral;
}
div div:nth-of-type(3) {
  background:lightsalmon;
}
div div:nth-of-type(4) {
  background:lightgreen;
}
div div:nth-of-type(5) {
  background:lightseagreen;
}
div div:nth-of-type(6) {
  background:lightskyblue;
}
div div:nth-of-type(7) {
  background:lightslategray;
}
div div:nth-of-type(8) {
  background:lightpink;
  order:-1;
}
div div:nth-of-type(9) {
  background:lightsteelblue;
}
div div:nth-of-type(10) {
  background:peru;
}