Menu Vertical Fixed Detail Summary

by kompiajaib

HTML

<nav id="Menu-holder">
    <div id="Menu">
  <details>
    <summary>Menu Item 1</summary>
    <a href="#" title="Sub Menu Item 1">Sub Menu Item 1</a>
    <a href="#" title="Sub Menu Item 2">Sub Menu Item 2</a>
    <a href="#" title="Sub Menu Item 3">Sub Menu Item 3</a>
  </details>
  <details>
    <summary>Menu Item 2</summary>
    <a href="#" title="Sub Menu Item 1">Sub Menu Item 1</a>
    <a href="#" title="Sub Menu Item 2">Sub Menu Item 2</a>
  </details>
  <details>
    <summary>Menu Item 3</summary>
    <a href="#" title="Sub Menu Item 1">Sub Menu Item 1</a>
    <a href="#" title="Sub Menu Item 2">Sub Menu Item 2</a>
    <a href="#" title="Sub Menu Item 3">Sub Menu Item 3</a>
    <a href="#" title="Sub Menu Item 4">Sub Menu Item 4</a>
    <a href="#" title="Sub Menu Item 5">Sub Menu Item 5</a>
  </details>
  <details>
    <summary>Menu Item 4</summary>
    <a href="#" title="Sub Menu Item 1">Sub Menu Item 1</a>
    <a href="#" title="Sub Menu Item 2">Sub Menu Item 2</a>
    <a href="#" title="Sub Menu Item 3">Sub Menu Item 3</a>
  </details>
</div>
    </nav>

CSS

body{ 
    margin:0px;
    height:2000px;background:#ddd
}
#Menu-holder {
    position:fixed;
    top:0;
    left:0;
    bottom:0;
	width: 15%;
	min-width: 200px;
    height:100%;
    background:#3c3c3c;
    padding:20px;
}
#Menu {
	width: 100%;
	min-width: 150px;
    font-family:Arial;
}
#Menu > details > summary{
	cursor:pointer;
	background: #26272a;
    box-shadow: 1px 1px 2px 0px rgba(0,0,0,0.75);
	margin:6px;
	padding:8px;
    outline:none;
    border-radius:3px;
    font-size:16px;
    color:#efefef;
    transition:all .3s ease-in-out;
}
#Menu > details > summary:hover{
	background: #424346;
}
#Menu > details > a{
	display:block;
	text-decoration: none;
	color:#efefef;
	font-size:14px;
	margin:4px 6px 4px 18px;
	padding:5px 8px;
	background: #424346;
    border-radius:2px;
    box-shadow: 1px 1px 2px 0px rgba(0,0,0,0.75);
    transition:all .3s ease-in-out;
}
#Menu > details > a:hover{
	background:#26272a;
}