b.css

/* The side navigation menu */
.sidenav {
    height: 100%; /* 100% Full-height */
    width: 0; /* 0 width - change this with JavaScript */
    position: fixed; /* Stay in place */
    z-index: 1; /* Stay on top */
    top: 0; /* Stay at the top */
    left: 0;
    background-color: #111; /* Black*/
    overflow-x: hidden; /* Disable horizontal scroll */
    padding-top: 60px; /* Place content 60px from the top */
    transition: 0.5s; /* 0.5 second transition effect to slide in the sidenav */
  }
  
  /* The navigation menu links */
  .sidenav a {
    padding: 8px 8px 8px 32px;
    text-decoration: none;
    font-size: 25px;
    color: #818181;
    display: block;
    transition: 0.3s;
  }
  
  /* When you mouse over the navigation links, change their color */
  .sidenav a:hover {
    color: #f1f1f1;
  }
  
  /* Position and style the close button (top right corner) */
  .sidenav .closebtn {
    position: absolute;
    top: 0;
    right: 25px;
    font-size: 36px;
    margin-left: 50px;
  }
  
  /* 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: 20px;
  }
  
  /* 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;}
  }
  .sidenav {
    right: 0;
  }
  /* The sidenav */
.sidenav {
    height: 100%;
    width: 200px;
    position: fixed;
    z-index: 1;
    top: 0;
    left: 0;
    background-color: #111;
    overflow-x: hidden;
    padding-top: 20px;
  }
  
  /* Page content */
  .main {
    margin-left: 200px; /* Same as the width of the sidenav */
  }
  /* Style the navigation bar */
.navbar {
    width: 100%;
    background-color: #555;
    overflow: auto;
  }
  
  /* Navbar links */
  .navbar a {
    float: right;
    text-align: center;
    padding: 12px;
    color: white;
    text-decoration: none;
    font-size: 17px;
  }
  
  /* Navbar links on mouse-over */
  .navbar a:hover {
    background-color: #000;
  }
  
  /* Current/active navbar link */
  .active {
    background-color: #04AA6D;
  }
  
  /* Add responsiveness - will automatically display the navbar vertically instead of horizontally on screens less than 500 pixels */
  @media screen and (max-width: 500px) {
    .navbar a {
      float: none;
      display: block;
    }
  }