screen orientation css

 @media screen and (orientation:portrait) { … }
 @media screen and (orientation:landscape) { … }

/* For portrait, we want the tool bar on top */

@media screen and (orientation: portrait) {
  #toolbar {
    width: 100%;
  }
}

/* For landscape, we want the tool bar stick on the left */

@media screen and (orientation: landscape) {
  #toolbar {
    position: fixed;
    width: 2.65em;
    height: 100%;
  }

  p {
    margin-left: 2em;
  }

  li + li {
    margin-top: .5em;
  }
}

@media (orientation: landscape) and (hover: none) and (pointer: coarse) {
/* your CSS to target only landscape mobile users */
}