body {
  margin:0;
}
.red {
  background:crimson;
  width: 70%;
}
.blue {
  background:skyblue;
  width: 30%;
}
.wrapper div {
  height: 300px;
  display:inline-block;
}
.wrapper {
  width: 800px;
  margin:50px auto;
  box-sizing:border-box;
}