<body data-spy="scroll" data-target="#navbar-example">


  <div class="wrapper" >

    <nav class="nav__wrapper" id="navbar-example">
      <ul class="nav">

        <li role="presentation" class="active">
          <a href="#section1">
            <span class="nav__counter">01</span>
            <h3 class="nav__title">Intro</h3>
            <p class="nav__body"><strong>Timeline-style navigation</strong>. Scroll down to see what happens, or click on a number in the nav.</p>
          </a>
        </li>

        <li role="presentation">
          <a href="#section2">
            <span class="nav__counter">02</span>
            <h3 class="nav__title">Section 2 Title</h3>
            <p class="nav__body">Sed sit amet justo sed odio tempus tempus. Vestibulum sed varius mi, sit amet condimentum lacus.</p>
          </a>
        </li>

        <li role="presentation">
          <a href="#section3">
            <span class="nav__counter">03</span>
            <h3 class="nav__title">Section 3 Title</h3>
            <p class="nav__body">Sed sit amet justo sed odio tempus tempus. Vestibulum sed varius mi, sit amet condimentum lacus.</p>
          </a>
        </li>
        
        <li role="presentation">
          <a href="#section4">
            <span class="nav__counter">04</span>
            <h3 class="nav__title">Section 4 Title</h3>
            <p class="nav__body">Sed sit amet justo sed odio tempus tempus. Vestibulum sed varius mi, sit amet condimentum lacus.</p>
          </a>
        </li>
        
        <li role="presentation">
          <a href="#section5">
            <span class="nav__counter">05</span>
            <h3 class="nav__title">Section 5 Title</h3>
            <p class="nav__body">Sed sit amet justo sed odio tempus tempus. Vestibulum sed varius mi, sit amet condimentum lacus.</p>
          </a>
        </li>
        
        <li role="presentation">
          <a href="#section6">
            <span class="nav__counter">06</span>
            <h3 class="nav__title">Section 6 Title</h3>
            <p class="nav__body">Sed sit amet justo sed odio tempus tempus. Vestibulum sed varius mi, sit amet condimentum lacus.</p>
          </a>
        </li>

      </ul>
    </nav>

    <section class="section section1" id="section1">
      Scroll down or use the nav.
    </section>

    <section class="section section2" id="section2">
      Section 2
    </section>

    <section class="section section3" id="section3">
      Section 3
    </section>

    <section class="section section4" id="section4">
      Section 4
    </section>

    <section class="section section5" id="section5">
      Section 5
    </section>

    <section class="section section6" id="section6">
      Section 6
    </section>


  </div>
</body>
.wrapper {
  min-height: 100vh;
  font-family: 'Roboto Slab', serif;
  font-weight: 300;
  color: #fff;
  position: relative; 
}

section {
  height: 100vh;
  font-size: 40px;
  font-weight: 100;
  background-color: #22A7F0;

  display: flex;
  justify-content: center;
  align-items: center;

  $colors: white, #F64747, #22A7F0, #F9690E, #9B59B6, #03C9A9, #ffcc00;
  @for $i from 1 through length($colors) {
    &:nth-child(#{$i}) {
      background: nth($colors, $i)
    }
  }
}

.nav {
  &__wrapper {
    position: fixed;
    height: 100%;
    padding: 30px;

    display: flex;
    flex-flow: column nowrap;
    justify-content: flex-end;
  }

  & {
    margin: 0 0 100px 30px; 
  }
  &__counter {
    font-size: 24px;
    transition: all 0.15s ease-out;
  }
  &__title {
    font-size: 32px;
    font-weight: 300;
    margin: 0 0 0.25em;
    width: 300px;
    height: 0;
    overflow: hidden;
    opacity: 0;
    transition: height 0.3s ease-out, opacity 0.2s ease-out;
  }
  &__body {
    font-weight: 100;
    font-size: 18px;
    font-size: 18px;
    width: 300px;
    height: 0;
    overflow: hidden;
    opacity: 0;
    transition: height 0.3s ease-out, opacity 0.2s ease-out;
  }

  li {
    position: relative;
    transition: all 0.3s ease-out;
    margin-bottom: 1em;

    &:after {
      content: '';
      display: block;
      border-left: 2px solid white;
      border-top: 2px solid white;
      height: 250px;
      width: 20px;
      position: absolute;
      left: -30px;
      top: 15px;
    }

    a {
      display: block;
      padding: 0;
      color: #fff;
      transition: all 0.15s ease-out;

      &:hover {
        background-color: transparent;
        padding-left: 1em
      }
      &:focus {
        background-color: transparent;
      }
    }

    &.active {
      pointer-events: none;
      padding-left: 1em;

      &:after {
        width: 35px;
        height: 400px;
        top: 35px;
      }

      .nav__counter {
        font-size: 48px;
      }
      .nav__title {
        height: 40px;
        opacity: 1;
        overflow: visible;
      }
      .nav__body {
        height: 100px;
        opacity: 1;
        overflow: visible;
      }
    }

  }

}
View Compiled
// SMOOTH SCROLLING SECTIONS
$('a[href*=#]:not([href=#])').click(function() {
    if (location.pathname.replace(/^\//,'') == this.pathname.replace(/^\//,'') 
        || location.hostname == this.hostname) {

        var target = $(this.hash);
        target = target.length ? target : $('[name=' + this.hash.slice(1) +']');
           if (target.length) {
             $('html,body').animate({
                 scrollTop: target.offset().top
            }, 1000);
            return false;
        }
    }
});

External CSS

  1. https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css
  2. https://maxcdn.bootstrapcdn.com/font-awesome/4.4.0/css/font-awesome.min.css
  3. https://fonts.googleapis.com/css?family=Roboto+Slab:400,100,300,700

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js
  2. https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js