body {
  margin: 0px;
  padding: 0px;
  font-family: Arial, Verdana, sans-serif;
  font-size: medium;
  font-weight: normal;
  background-image: url(./img_night_sky.jpg);
  background-attachment: fixed;
  }

/* menu button styles */

.menu_button {
  width: 50px;
  height: 25px;
  margin: 0px;
  padding: 0px;
  border: 2px solid LightBlue;
  border-radius: 8px;
  font-size: 16px;
  font-weight: bold;
  color: DarkBlue;
  background-color: ivory;
  vertical-align: middle;
  transition-duration: 0.5s;
  float: left;
  display: block;
  }
 .menu_button:hover {
  cursor: pointer;
  background-color: LightBlue;
  }

/* main menu styles */

.menulist {
  margin: 0px;
  padding: 0px;
  }
.menuitem {
  font-size: medium;
  color: LightYellow;
  border: 1px solid Blue;
  border-radius: 4px;
  background: MediumBlue;
  opacity: 0.8;
  margin: 3px;
  padding: 2px;
  list-style-type: none;
  transition-duration: 0.5s;
  }
.menuitem:hover {
  color: Black;
  background: Ivory;
  cursor: pointer;
  box-shadow: 0px 0px 10px lightblue;
  }

/* text styles */

.neo {
  font-size: x-large;
  font-weight: bold;
  color: LightBlue;
  text-shadow: 0px 0px 10px;
  }

 h1, h2 {
  color: Gold;
  text-align: center;
  text-shadow: 0px 0px 5px;
  }
 h3 {
  color: LightYellow;
  text-align: center;
  text-shadow: 0px 0px 2px;
  }
 h4 {
  color: LightYellow;
  text-align: right;
  text-shadow: 0px 0px 2px;
  }

/* div & flex div styles */

#top_div {
  margin: 5px;
  padding: 5px;
  border: 0px solid red;
  width: auto;
  text-align: center;
  }

#menu_div {
  margin: 0px;
  padding: 0px;
  border: 0px solid red;
  flex-grow: 0;
  flex-shrink: 0;
  display: block;

  position: absolute;
  left: 0px;
  top: 50px;
  z-index: 3;

  }

#flex_div {
  display: flex;
  flex-direction: column;
  }

#left_div {
  margin: 0px;
  padding: 0px;
  border: 0px solid red;
  flex-grow: 2;
  background-image: url(./img_andromeda_left.jpg);
  background-position: left;
  background-size: cover;
  display: none;
  }

#center_div {
  width: auto;
  margin: 0px;
  padding: 0px;
  border: 0px solid red;
  flex-grow: 10;
  display: block;
  }

#right_div {
  margin: 0px;
  padding: 0px;
  border: 0px solid red;
  flex-grow: 2;
  background-image: url(./img_andromeda_right.jpg);
  background-position: right;
  background-size: cover;
  display: none;
  }

@media screen and (min-width: 601px) and (max-width: 900px) {
  #flex_div {flex-direction: row;}
  #center_div {display: block;}
  #left_div {display: none;}
  #right_div {display: block;}
  }

@media screen and (min-width: 901px) {
  #flex_div {flex-direction: row;}
  #center_div {display: block;}
  #left_div {display: block;}
  #right_div {display: block;}
  }