body {
  margin: 0px;
  background-color: black;
}

p {
  font-size: 22px;
  font-weight: bold;
  margin: 0px;
}

#top-menu {
  width: 100%;
  height: 120px;
  
  position: relative;
}

.le-button {
  width: 250px;
  height: 110px;
  border-radius: 5px;
    
  background-color: red;
  
  margin-top: 5px;
  margin-right: 5px;
  margin-left: auto;
  float: right;
}

 
@media only screen and (min-device-width: 320px) and (max-device-width: 639px) {
  /* Hier der CSS Code für Smartphones wie z.B. iPhone, Android, WebOS, Windows Phone 7 Geräte o.Ä. */

  #top-menu {  
    background-color: yellow;
  }
}
 
/* Computer und Tablet CSS */
@media only screen and (min-device-width: 800px) {
  /* Hier der CSS-Code für Tablets und Computer ab einer mindest Bildschirm Weite von 800 Pixeln */

  #top-menu {
    background-color: orange;
  }
}