style.css

body {
  overflow-x: hidden;
  font-family: Helvetica, Arial, sans-serif;
  margin: 0; }

p {
  line-height: 1.5em; }

#navMenu {
  height: 100%;
  width: 0;
  position: fixed;
  z-index: 1;
  top: 0;
  left: -400px;
  background: #000;
  overflow-x: hidden; }
  #navMenu ul {
    padding: 0;
    margin: 0; }
  #navMenu a {
    padding: 1em 1.25em;
    text-decoration: none;
    color: #ccc;
    display: block;
    border-bottom: 1px solid #444;
    transition: .25s; }
    #navMenu a:hover {
      background: #333;
      color: #fff; }
  #navMenu.open {
    width: 400px;
    left: 0; }

/* Style page content - use this if you want to push the page content to the right when you open the side navigation */
#main {
  transition: margin-left .5s;
  padding: 1em;
  left: 0;
  position: relative; }

#main.open {
  left: 400px; }

/* On smaller screens, where height is less than 450px, change the style of the sidenav (less padding and a smaller font size) */
@media screen and (max-height: 450px) {
  .sidenav {
    padding-top: 15px; }

  .sidenav a {
    font-size: 18px; } }
#navBtn {
  width: 2em;
  height: 1.5em;
  position: relative;
  transform: rotate(0deg);
  transition: .5s ease-in-out;
  cursor: pointer; }
  #navBtn span {
    display: block;
    position: absolute;
    height: .3em;
    width: 100%;
    background: #000;
    border-radius: 1em;
    opacity: 1;
    left: 0;
    transform: rotate(0deg);
    transition: .25s ease-in-out; }
    #navBtn span:nth-child(1) {
      top: 0; }
    #navBtn span:nth-child(2), #navBtn span:nth-child(3) {
      top: .55em; }
    #navBtn span:nth-child(4) {
      top: 1.15em; }
  #navBtn.open span:nth-child(1) {
    top: .55em;
    width: 0%;
    left: 50%; }
  #navBtn.open span:nth-child(2) {
    transform: rotate(45deg); }
  #navBtn.open span:nth-child(3) {
    transform: rotate(-45deg); }
  #navBtn.open span:nth-child(4) {
    top: .55em;
    width: 0%;
    left: 50%; }
  #navBtn:hover span {
    transition: .25s;
    background: #ff9900; }
  #navBtn:hover span:nth-child(1) {
    top: -.1em; }
  #navBtn:hover span:nth-child(4) {
    top: 1.27em; }