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CSS

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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

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JavaScript

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HTML 

              
                <h3> Linear timeline from left to right </h3>
<div id="horizontal-timeline" class="timeline horizontal reverse">
  <div class="block">
    <div class="square up">
      <h3>Main title</h3>
      <h4>date</h4>
      <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.</p>
    </div>
    <div class="circle">
      <p>2010</p>
    </div>
    <div class="link"></div>
    <div class="square down blank"></div>
  </div>
  <div class="block">
    <div class="square up blank"></div>
    <div class="circle activated">
      <p>2011</p>
    </div>
    <div class="link"></div>
    <div class="square down">
      <h3>Main title</h3>
      <h4>date</h4>
      <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.</p>
    </div>
  </div>
  <div class="block">
    <div class="square up">
      <h3>Main title</h3>
      <h4>date</h4>
      <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.</p>
    </div>
    <div class="circle">
      <p>2014</p>
    </div>
    <div class="link"></div>
    <div class="square down blank"></div>
  </div>
  <div class="block">
    <div class="square up blank"></div>
    <div class="circle">
      <p>2016</p>
    </div>
    <div class="link"></div>
    <div class="square down">
      <h3>Main title</h3>
      <h4>date</h4>
      <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.</p>
    </div>
  </div>

  <div class="block">
    <div class="square up">
      <h3>Main title</h3>
      <h4>date</h4>
      <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.</p>
    </div>
    <div class="circle">
      <p>2017</p>
    </div>
    <div class="link"></div>
    <div class="square down blank"></div>
  </div>
  <div id="end"></div>
</div>

<!-- Second linear timeline -->
<h3> Linear timeline from top to bottom </h3>
<div id="vertical-timeline" class="timeline vertical">
  <div class="block">
    <div class="square right">
      <h3>Main title</h3>
      <h4>date</h4>
      <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.</p>
    </div>
    <div class="circle">
      <p>2010</p>
    </div>
    <div class="link"></div>
    <div class="square left blank"></div>
  </div>

  <div class="block">
    <div class="square right blank"></div>
    <div class="circle">
      <p>2011</p>
    </div>
    <div class="link"></div>
    <div class="square left">
      <h3>Main title</h3>
      <h4>date</h4>
      <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.</p>
    </div>
  </div>

  <div class="block">
    <div class="square right">
      <h3>Main title</h3>
      <h4>date</h4>
      <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.</p>
    </div>
    <div class="circle activated">
      <p>2013</p>
    </div>
    <div class="link"></div>
    <div class="square left blank"></div>
  </div>

  <div class="block">
    <div class="square right blank"></div>
    <div class="circle">
      <p>2015</p>
    </div>
    <div class="link"></div>
    <div class="square left">
      <h3>Main title</h3>
      <h4>date</h4>
      <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.</p>
    </div>
  </div>

  <div class="block">
    <div class="square right">
      <h3>Main title</h3>
      <h4>date</h4>
      <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.</p>
    </div>
    <div class="circle">
      <p>5</p>
    </div>
    <div class="link"></div>
    <div class="square left blank"></div>
  </div>
  <div id="end"></div>
</div>
!

CSS 

              
                /* General code */
@import url(https://fonts.googleapis.com/css?family=Barlow+Condensed);
body {
  font-family: "Barlow Condensed";
  margin: auto;
  width: 100%;
  justify-content: center;
  display: flex;
  flex-direction: column;
  text-align: center;
  font-size: 16px;
}
button {
  width: 100px;
  margin: auto;
}
.timeline {
  display: flex;
  margin: auto;
  justify-content: center;
}
.timeline .circle {
  width: 30px;
  height: 30px;
  border-radius: 30px;
  background-color: #a8d0f7;
  margin: 0;
  padding: 2px;
  margin-left: -5px;
  z-index: 2;
  position: relative;
}
.timeline .circle:hover {
  cursor: pointer;
}
.timeline .circle p {
  text-align: center;
  margin: auto;
  line-height: 30px;
  color: #ffffff;
}
.timeline .link {
  z-index: 0;
  background-color: #a8d0f7;
  padding: 0;
}
.square {
  max-width: 250px;
  min-width: 100px;
  height: 115px;
  border-radius: 10px;
  background-color: rgb(176, 179, 204);
  z-index: 2;
  position: relative;
}
.square.blank {
  visibility: hidden;
}
#end {
  width: 0;
  height: 0;
}
.square h3,
.square h4 {
  margin: 0px 0px 0px 15px;
  text-align: left;
  font-size: 16px;
}
.square h3 {
  padding-top: 5px;
}
.square h4 {
  font-style: italic;
  font-weight: normal;
}

/* Linear timeline from left to right */
#horizontal-timeline {
  flex-direction: row;
  min-width: 1100px;
}
.horizontal .link {
  width: auto;
  height: 5px;
  margin-top: -15px;
  margin-left: 5px;
}
.horizontal .square {
  margin: 30px 0 20px -30px;
}
.horizontal .square p {
  padding: 0;
  margin: 0;
  width: 100%;
}
.square.up::after {
  margin: 12px 0px 0px 10px;
  border-left: 20px solid transparent;
  border-right: 20px solid transparent;
  border-top: 20px solid rgb(176, 179, 204);
}

.square.down::after {
  margin: -108px 0 15px 15px;
  border-left: 20px solid transparent;
  border-right: 20px solid transparent;
  border-bottom: 20px solid rgb(176, 179, 204);
}
.horizontal #end {
  margin: 175px 0;
  border-top: 10px solid transparent;
  border-bottom: 10px solid transparent;
  border-left: 10px solid #a8d0f7;
}

/* Linear timeline from top to bottom */
.vertical .block {
  display: flex;
  flex-direction: row;
}
#vertical-timeline {
  flex-direction: column;
}
.vertical .link {
  width: 5px;
  height: 150px;
  margin-top: 0;
  margin-left: -20px;
}
.vertical .square {
  width: 250px;
  margin: 0px 25px 0px 35px;
}
.vertical .square p {
  padding: 0;
  margin: 0;
}
.vertical #end {
  border-left: 10px solid transparent;
  border-right: 10px solid transparent;
  border-top: 10px solid #a8d0f7;
  margin: auto;
  margin-left: 311px;
}
.square::after {
  content: " ";
  display: block;
  z-index: 0;
  width: 0px;
  height: 0px;
}
.square.left::after {
  margin: -70px 11px 0px -15px;
  border-top: 20px solid transparent;
  border-bottom: 20px solid transparent;
  border-right: 20px solid rgb(176, 179, 204);
}
.square.right::after {
  margin: -75px 0px 0px 242px;
  border-top: 20px solid transparent;
  border-bottom: 20px solid transparent;
  border-left: 20px solid rgb(176, 179, 204);
}
!

JS 

              
                var vTimeline = document.getElementById("horizontal-timeline");
var hTimeline = document.getElementById("vertical-timeline");
activation(vTimeline);
activation(hTimeline);

function activation(timeline) {
  var divs = timeline.getElementsByTagName("div");
  for (var i = 0; i < divs.length; i++) {
    if (
      divs[i].classList.contains("circle") ||
      divs[i].classList.contains("link")
    ) {
      divs[i].style.background = "#05A5D1";
      if (divs[i].classList.contains("activated")) {
        break;
      }
    }
  }
}
!
999px

Console