Division not showing! Why? [duplicate]

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• Basic height percentage 3 answers

So i have been working on making a website for me and my friends, and until now i have made the menu bar, and a communication space ( with <div>s). But I don't seem to make the second div to show up. Where is my problem? Why doesn't it show up? Here's my code:

#MenuBar {
  width: 100%;
  height: 10%;
  background-color: blue;
  border-radius: 30px;
  position: center;
  display: fixed;
}
body {
  background-color: black;
  background-repeat: no-repeat;

}
#MenuTabs {
  width:  75%;
  height: 75%;
  color: white;
  position: center;
}
#Messenger {
  width: 50%;
  height: 50%;
  background-color: white;
  display: fixed;
}

<!-- The menu tab -->
<div id="MenuBar">
  <table id="MenuTabs" cellspacing="1%" align="center">
    <tr>
      <td>Home</td>
      <td>Lessons</td>
      <td>Playground</td>
      <td>About</td>
    </tr>
  </table>
</div>
<!-- Communication Tab-->
<div id="Messenger"></div>

As you can see, it only shows the menu bar, but it doesnt show the white-background div. Can you please help me with that?