JSFiddle - React, Tailwind, and code Playground

HTML

<div id="nav">
<ul>
<div class="active"><li><a href="#hello">Hello</a></li></div>
<li><a href="#about">About</a></li>
<li><a href="#yolo">Yolo</a></li>
<li><a href="#swag">Swag</a></li>
</ul>
</div>
<div id="wrapper">
<div id="hello">
<a id="hello">hello</a>
</div>
<div id="about">
<a id="about">about</a>
</div>
<div id="yolo">
<a id="yolo">yolo</a>
</div>
<div id="swag">
<a id="swag">swag</a>
</div>
</div>

CSS

body {
	background-image: url(../images/noise.png);
	background-repeat: repeat;
	width:100%;
	height: 100%;
}
#wrapper {
	float: left;
	width: 80%;
	max-width: 960px;
	background-image: url(../images/white.png);
	background-repeat: repeat;
}
#nav {
	font-family: 'Asap', sans-serif;
	font-weight: 700;
	font-size: 20px;
	position: fixed;
	left: 0px;
	top: 20%;
	list-style-type: none;	
	color: #000;
}
#nav li {
	cursor: pointer;
	width: 100px;
	margin-bottom: 10px;
	padding: 3px;
	text-align: right;
	-webkit-transition-duration: 0.4s;
    -moz-transition-duration: 0.4s;
    -o-transition-duration: 0.4s;
    transition-duration: 0.4s;
}
#nav li:hover {
	width: 120px;
}
li a {
	text-decoration: none;
	color: #000;
}
li:hover a {
	color: #CDCDCD;
}
.active {
}
.active a {
	color: #CDCDCD;
}
.active li {
	padding-left: 20px;
}
#hello {
	width:100%;
	height: 1000px;
}
#about {
	width:100%;
	height: 1000px;
}
#yolo {
	width:100%;
	height: 1000px;
}
#swag {
	width:100%;
	height: 1000px;
}

JavaScript

var lastId,
    topMenu = $("#nav"),
    topMenuHeight = topMenu.outerHeight()+15,
    menuItems = topMenu.find("a"),
    scrollItems = menuItems.map(function(){
      var item = $($(this).attr("href"));
      if (item.length) { return item; }
    });
menuItems.click(function(e){
  var href = $(this).attr("href"),
      offsetTop = href === "#" ? 0 : $(href).offset().top-topMenuHeight+1;
  $('html, body').stop().animate({ 
      scrollTop: offsetTop
  }, 300);
  e.preventDefault();
});
$(window).scroll(function(){
   var fromTop = $(this).scrollTop()+topMenuHeight;
   var cur = scrollItems.map(function(){
     if ($(this).offset().top < fromTop)
       return this;
   });
   cur = cur[cur.length-1];
   var id = cur && cur.length ? cur[0].id : "";
   
   if (lastId !== id) {
       lastId = id;
       menuItems
         .parent().removeClass("active")
         .end().filter("[href=#"+id+"]").parent().addClass("active");
   }                   
});