position:fixed
<input type="checkbox" name="click" id="click"/>
<div class="tolab">
<label for="click">show/hide menu</label>
</div>
<nav>
<ul>
<li>Item1</li>
<li>Item2</li>
<li>Item3</li>
<li>Item4</li>
<li>Item5</li>
</ul>
</nav>
body{
background:grey;
margin:0;
}
nav{
background:black;
color:white;
position:fixed;
margin-top:50vh;
display:none;
padding-right:1em;
}
nav li{
background:brown;
color:orange;
border:1px solid yellow;
}
#click:checked ~ nav{
display:block;
}
input{
display:none;
}
.tolab{
text-align:center;
margin-left:auto;
margin-right:auto;
}
li:hover{
background:black;
cursor:pointer;
}