.container {
  display: flex;
  flex-direction: column;
}

.container__main {
  /* Take the remaining height */
  flex-grow: 1;
  /* Layout the left sidebar, main content and right sidebar */
  display: flex;
  flex-direction: row;
  padding-top: 1em;
  margin-left: 10%;
  margin-right: 10%;
}

.container__left {
  width: 10%;
}

.container__middle {
  /* Take the remaining width */
  flex-grow: 1;
}

.container__right {
  width: 10%;
}