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HTML

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About the <head>

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CSS

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CSS Base

About CSS Base

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JavaScript

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Babel includes JSX processing.

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HTML 

              
                <div class="wrapper">

  <h1>Tooltips</h1>

  <div>
    <a href="https://www.twitter.com" target="_blank" class="tooltip">
      <i class="fa fa-twitter"></i><span class="tip">Follow Us On Twitter</span>
    </a>
  </div>
  <div>
    <a href="https://www.facebook.com" target="_blank" class="tooltip">
      <i class="fa fa-facebook"></i><span class="tip">Like Our Facebook Page</span>
    </a>
  </div>

  <p>&nbsp;</p>

  <h1>Citations</h1>

  <p>My father had a small estate in Nottinghamshire: <sup><a href="#footnote">[1]</a> <span><cite><a href="https://www.gutenberg.org/files/829/829-h/829-h.htm" target="_blank">Gulliver's Travels </a></cite> by Jonathan Swift, 1726</span></sup> I was the third of five sons. He sent me to Emanuel College in Cambridge at fourteen years old, where I resided three years, and applied myself close to my studies; but the charge of maintaining me,<sup>[2] <span>Part I: A Voyage to Lilliput</span></sup> although I had a very scanty allowance, being too great for a narrow fortune, I was bound apprentice to Mr. James Bates,<sup>[3] <span>Part II: A Voyage to Brobdingnag</span></sup> an eminent surgeon in London, with whom I continued four years.</p>

  <div class="footnotes">
    <p id="footnote">1. ^ If you need footnotes this works too</p>
    <p>2. ^ Another example footnote for demonstration purposes</p>
    <p>3. ^ One more demonstrative footnote here</p>
  </div>

</div>
!

CSS 

              
                * {
  box-sizing: border-box;
}
body {
  font-family: "Open Sans";
  line-height: 1.618em;
  color: #555;
  background: #2c3e50;
}
.wrapper {
  max-width: 50rem;
  width: 100%;
  margin: 2rem auto;
  padding: 5rem;
  background: #fff;
  border: 0.5rem solid #34495e;
}
a {
  text-decoration: none;
  color: #3498db;
}
.fa {
  font-size: 4rem;
  margin: 1rem;
}
.fa-twitter {
  color: #00b0ed;
}
.fa-facebook {
  color: #3b5998;
}
.tooltip {
  position: relative;
}
.tooltip:hover .tip {
  opacity: 1;
  visibility: visible;
  margin-left: 0.5rem;
  transition: all 0.35s;
}
.tip {
  opacity: 0;
  visibility: hidden;
  display: block;
  white-space: nowrap;
  position: absolute;
  z-index: 1;
  left: 100%;
  bottom: 50%;
  padding: 1em;
  margin-left: 0;
  margin-top: 0.5rem;
  font-size: 0.8em;
  font-weight: normal;
  background: #34495e;
  border-radius: 1em;
  color: #fff;
  transition: all 0.35s;
}
.tip::before {
  content: '';
  border-style: solid;
  border-width: 0.5rem 0.625rem 0.5rem 0;
  border-color: transparent #34495e transparent transparent;
  position: absolute;
  right: 100%;
  bottom: calc(50% - 0.5rem);
  width: 0;
  height: 0;
}
sup {
  position: relative;
  cursor: pointer;
}
sup span {
  cursor: default;
  background: #ecf0f1;
  border: 0.125rem solid #3498db;
  position: absolute;
  left: 0;
  bottom: 100%;
  margin: 0 0 0.7em -1em;
  width: 12em;
  padding: 1em;
  line-height: 1.618em;
  opacity: 0;
  visibility: hidden;
  transition: all 0.35s;
}
sup span::before {
  content: '';
  border-style: solid;
  border-width: 0.7em 0.7em 0 0.7em;
  border-color: #3498db transparent transparent transparent;
  position: absolute;
  left: 0.7em;
  bottom: -0.7em;
  width: 0;
  height: 0;
}
sup:hover span {
  opacity: 1;
  visibility: visible;
  transition: all 0.35s;
}
.footnotes {
  margin: 60rem auto;
}
#footnote:target {
  background: #ecf0f1;
}
!

JS
!
999px

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