RESPONSIVE TIMELINE
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<!DOCTYPE html>
<html lang="en">
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>HTML</title>
<style>	
	html, body {
	  margin: 0;
	  padding: 0;
	  font-family: Helvetica, sans-serif;
	}
	body {
	  background: #25303B;
	}
	
	.timeline {
	  position: relative;
	  width: 80%;
	  margin: 20px auto;
	}

	
	.timeline::after {
	  content: '';
	  position: absolute;
	  width: 6px;
	  background-color: white;
	  top: 0;
	  bottom: 0;
	  left: 50%;
	  margin-left: -3px;
	}

	
	.container {
	  padding: 10px 40px;
	  position: relative;
	  background-color: inherit;
	  width: 50%;
	}

	/* The circles on the timeline */
	.container::after {
	  content: '';
	  position: absolute;
	  width: 25px;
	  height: 25px;
	  right: -17px;
	  background-color: white;
	  border: 3px solid blue;
	  top: 16px;
	  border-radius: 50%;
	  z-index: 1;
	}

	
	.left {
	  left: 0;
	}

	
	.right {
	  left: 50%;
	}

	
	.left::before {
	  content: " ";
	  height: 0;
	  position: absolute;
	  top: 22px;
	  width: 0;
	  z-index: 1;
	  right: 30px;
	  border: medium solid white;
	  border-width: 10px 0 10px 10px;
	  border-color: transparent transparent transparent white;
	}

	/* Add arrows to the right container (pointing left) */
	.right::before {
	  content: " ";
	  height: 0;
	  position: absolute;
	  top: 20px;
	  width: 0;
	  z-index: 1;
	  left: 30px;
	  border: 2px solid blue;
	  border-width: 10px 10px 10px 0;
	  border-color: transparent white transparent transparent;
	}

	/* Fix the circle for containers on the right side */
	.right::after {
	  left: -16px;
	}

	/* The actual content */
	.content {
	  padding: 20px 30px;
	  background-color: white;
	  position: relative;
	  border-radius: 6px;
	}
   h2 {
     color: green;
   }
	
	@media screen and (max-width: 600px) {
	/* Place the timelime to the left */
	  .timeline::after {
		left: 30px;
	  }

	
	  .container {
		width: 100%;
		padding-left: 75px;
		padding-right: 20px;
	  }

	/* Make sure that all arrows are pointing leftwards */
	  .container::before {
		left: 60px;
		border: medium solid white;
		border-width: 10px 10px 10px 0;
		border-color: transparent white transparent transparent;
	  }

	/* Make sure all circles are at the same spot */
	  .left::after, .right::after {
		left: 15px;
	  }

	/* Make all right containers behave like the left ones */
	  .right {
		left: 0%;
	  }
	}

</style>
</head>  
<body>
    
	<div class="timeline">
	  <div class="container left">
		<div class="content">
		  <h2>2019</h2>
		  <p>The Foundation day </p>
		</div>
	  </div>
	  <div class="container right">
		<div class="content">
		  <h2>2020</h2>
		  <p>Annual Meet </p>
		</div>
	  </div>
	</div>
</body>
</html>