I am trying to make a menu on the left side showing the content on the right without using JavaScript. 

```css
.treeview ul{ /*CSS for Simple Tree Menu*/
margin: 0;
padding: 0;
}

.treeview li{ /*Style for LI elements in general (excludes an LI that contains sub lists)*/
background: white no-repeat left center;
list-style-type: none;
padding-left: 22px;
margin-bottom: 3px;
}

.treeview li.submenu{ /* Style for LI that contains sub lists (other ULs). */
background: white url(list.gif) no-repeat left 1px;
cursor: hand !important;
cursor: pointer !important;
}

.treeview li.submenu ul{ /*Style for ULs that are children of LIs (submenu) */
display: none; /*Hide them by default. Don't delete. */
}

.treeview .submenu ul li{ /*Style for LIs of ULs that are children of LIs (submenu) */
cursor: default;
}

div.container {
    width: 100%;
    border: 3px solid gray;
}

header, footer {
    padding: 1em;
    color: white;
    background-color: black;
    clear: left;
    text-align: center;
}

nav {
    float: left;
    max-width: 250px;
    margin: 0;
    padding: 2em;
}

nav ul {
    list-style-type: none;
    padding: 0;
}

nav ul a {
    text-decoration: none;
}

article {
 position:relative;
    margin-left: 160px;
    border-left: 1px solid gray;
    padding: 10em;
    overflow: hidden;
}
```

```html
<!DOCTYPE html>
<html>
<head>

<link rel="stylesheet" type="text/css" href="simpletree.css" />

</head>
<body>

<div class="container">

<header>
   <h1>Documentation</h1>
</header>

<nav>
<h4>Main Menu:</h4>

<ul id="treemenu" class="treeview">
<div class="collapse" tabindex="1">
<a href=""><li>Menu 1</li></a>
</div>
<li>Menu 2</li>

<li>Menu 3
 <ul>
 <li>Sub Item 3.1</li>
 <li>Sub Item 3.2</li>
 </ul>
</li>
<li>Menu 4</li>
<li>Menu 5
 <ul>
 <li>Sub Item 5.1</li>
 <li>Menu 5.1
  <ul>
  <li>Sub Item 5.1.1</li>
  <li>Sub Item 5.1.2</li>
  </ul>
 </li>
</ul>
</li>

<li>Menu 6</li>
</ul>

</nav>

<article>
  <h1>Menu 1</h1>
  <p>Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.</p>
  <p>Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.</p>
  <p>Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.</p>
  <p>Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.</p>
  <p>Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.</p>
  </article>

<footer></footer>

</div>

</body>
</html>
```

I'm not able to create showing the content on the right on click on Menu1 and then removing the content and showing another content clicking on Menu2 using only pure HTML/CSS