.container {
  width: 70%;
  margin: 0 auto;
}

.main-l {
  float: left;
  width: 60%;
}

.main-r {
  float: right;
  width: 40%;
}

.main-b {
  float: right;
  width: 40%;
}

/* Portrait */
@media only screen and (max-width: 600px) {
  .main-l {
    width: 100%;
  }

  .main-r {
    width: 100%;
  }

  .main-b {
    width: 100%;
  }
}