<style>
#menu {
position: fixed;
right: 0;
top: 50%;
width: 15em;
margin: -2.5em 0 0 0;
z-index: 5;
background: hsla(80, 90%, 40%, 0.7);
color: white;
font: Georgia, "Times New Roman", Times, serif;
font-weight: normal;
font-size: 100%;
text-align: left;
border: solid hsla(80, 90%, 40%, 0.5);
border-right: none;
padding: 0.5em 0.5em 0.5em 2.5em;
box-shadow: 0 1px 3px black;
border-radius: 3em 0.5em 0.5em 3em;
}
#menu li { margin: 0 }
#menu a { color: inherit }
/* Make menu absolute, not fixed, on IE 5 & 6 */
#menu { position: absolute }
*>#menu { position: fixed }
</style>
<ol id=menu>
<li><a href="#Introduction" target="">Introduction</a></li>
<li><a href="#How_to_install" target="">How to install</a></li>
<li><a href="#Summary" target="">Summary</a></li>
<li><a href="#References" target="">References</a></li>
<li><a href="#Quiz_Answers" target="">Quiz Answers</a></li>
</ol>
Custom menu CSS style in a markdown cell