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HTML

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HTML preprocessors can make writing HTML more powerful or convenient. For instance, Markdown is designed to be easier to write and read for text documents and you could write a loop in Pug.

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Adding Classes

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About the <head>

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Insecure Resource

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CSS

About CSS Preprocessors

CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.

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CSS Base

About CSS Base

It's a common practice to apply CSS to a page that styles elements such that they are consistent across all browsers. We offer two of the most popular choices: normalize.css and a reset. Or, choose Neither and nothing will be applied.

Vendor Prefixing

About Vendor Prefixing

To get the best cross-browser support, it is a common practice to apply vendor prefixes to CSS properties and values that require them to work. For instance -webkit- or -moz-.

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JavaScript

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JavaScript preprocessors can help make authoring JavaScript easier and more convenient.

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Babel includes JSX processing.

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HTML 

              
                <nav role="navigation">
  <h1>Peek menu</h1>
  
  <!--Dear copy/pasters. This is not very accessable and is more of a prototype. You may want to do work to make this div a button and review the code to make sure it meets your accessability needs.-->
  <div class="pub-steps" id="dropdown" onclick="dropdown(this)">
    <a href="#" rel="external" class="actionable is-above" onclick="select(this)">First</a>
    <a href="#" rel="external" class="actionable is-active" onclick="select(this)">Second</a>
    <a href="#" rel="external" class="actionable" onclick="select(this)">Third</a>
    <a href="#" rel="external" class="actionable" onclick="select(this)">Fourth</a>
  </div>
</nav>

<article>
  <h1>The Peek Menu</h1>
  <p>In designing new navigation for our writing app at <a href="http://www.voxmedia.com/careers">Vox Media</a> we tested a design with a dropdown menu indicating the current state. The menu performed poorly as it didn’t do a good job of showing there were other options underneath it. As a result we went back to the drawing board and did a total overhaul of our navigation system including removing the hamburger menu which are really filled with mystery meat, you never know what’s inside of them until you click on them. Our effort to make a more intuitive and transparent navigation lead us to do many things, including the creation of a new navigation pattern I’ll call the “peek menu”. This menu is the small screen variant of a tabbed menu that packs a lot of information into a small space. There are lines like a hamburger menu but each line represents an item in the list as well as a highlighted line for the currently active item. Other menu items in the list are left partially exposed to help indicate the context around the current selection and that there are more buried options.</p>
</article>
!

CSS 

              
                $pub-steps: 4;
$color: #05C3ED;
$speed: .25s;
$height: 42px;
$background: #000;
$text: #fff;

@import url(https://fonts.googleapis.com/css?family=Roboto:300|Open+Sans);

* {
  margin: 0;
  padding: 0;
  color: inherit;
  text-decoration: inherit;
  font-weight: inherit;
  font-size: 1em;
  line-height: inherit;
  box-sizing: border-box;
}

body {
  font-family: 'Open Sans',sans-serif;
  font-weight: 300;
  font-size: 14px;
  padding-top: $height;
}

nav {
  position: fixed;
  top: 0;
  width: 100%;
  font-family: Roboto,sans-serif;
  color: #fff;
  padding: 0 0 0 1rem;
  background: #333;
  height: $height;
  line-height: $height;
  min-width: 12em;
  box-shadow: 0 2px 0 0 rgba(#000,.1);
  h1 {
    float: left;
  }
}

.pub-steps {
  font-size: 12px;
  height: $height;
  overflow: hidden;
  position: relative;
  padding: .85rem 0;
  transition: padding $speed;
  background: $background;
  cursor: pointer;
  float: right;
  &.is-active {
    height: auto;
  }
  .actionable {
    display: block;
    margin: -18px .5rem 4px 1.2rem;
    transition: margin $speed, color $speed;
    pointer-events: none;
    line-height: 1.2;
    background: $background;
    color: $background;
    &.is-above {
      color: #aaa;
    }
    &.is-active {
      margin-top: 0;
      color: #fff;
      & ~ .actionable {
        color: #aaa;
        margin-top: 0;
      }
    }
    &:after {
      content: '';
      display: block;
      position: absolute;
      width: 6px;
      height: 2px;
      background: #999;
      left: 4px;
      transition: width $speed;
      z-index: 2;
    }
    &.is-active:after {
      width: 8px;
      background: $color;
    }
    @for $i from 1 through nth($pub-steps,1) {
      &:nth-child(#{$i}):after {
        top: ($height / 2) - (4px * nth($pub-steps,1) / 2) + 1px + (4px * ($i - 1));
      }
    }
  }
  &:before,
  &:after {
    content: '';
    position: absolute;
    height: .5rem;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 1;
    background-image: linear-gradient(transparent, $background);
  }
  &:before {
    top: 0;
    background-image: linear-gradient($background, transparent);
  }
  &.is-active {
    height: auto;
    padding: .2rem 0;
    z-index: 2;
    cursor: auto;
    .actionable {
      color: #aaa;
      pointer-events: auto;
      margin: 12px .5rem 12px 1.2rem;
      &.is-active {
        color: #fff;
      }
      &:hover:after {
        width: 8px;
      }
    }
  }
}

article {
  padding: 5% 5% 15%;
  margin: 0 auto;
  max-width: 40em;
  line-height: 1.5;
  h1 {
    font-size: 2em;
  }
  a {
    color: darken($color,20%);
    text-decoration: underline;
    &:hover {
      color: darken($color,10%);
    }
  }
}
!

JS 

              
                var dropdown = function(t) {
  t.classList.toggle('is-active');
}

var select = function(t) {
  var isactive = document.getElementsByClassName('is-active');
  var isabove = document.getElementsByClassName('is-above');

  isactive[1].classList.remove('is-active');
  t.classList.add('is-active');
  
  if(isabove[0]) {
    isabove[0].classList.remove('is-above');
  }
  if(t.previousSibling.previousSibling) {
    t.previousSibling.previousSibling.classList.add('is-above');
  }
}
!
999px

Console