app.component.css

#top-container {
  width: 100%;
  display: flex;
}

#left-menu {
  border: 1px solid green;
}



#contentarea {
  border: 1px solid blue;
  flex-grow: 1;
  display: flex;
  flex-direction: column;
}

#topbar {
  margin-bottom: 30px;
}

#content {
  border: 1px solid yellow;
  display: flex;
  flex-direction: row;
}