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HTML 

              
                <!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style media="screen">
  *,
*:before,
*:after {
margin: 0;
padding: 0;
box-sizing: border-box;
}

html {
font-size: 100%;
}

body {
width: 100%;
height: 100vh;
overflow: hidden;
display: grid;
place-items: center;
background: rgb(12, 141, 195);
font-family: "Lato", sans-serif;
font-weight: 400;
line-height: 1.75;
}

p {
margin-bottom: 1rem;
}

h1{
  background: rgb(11, 108, 161);
  color: white;
  font-size: 27px;
  text-align: center;
  margin-top: -17px;
  margin-left: -17px;
  margin-right: -17px;
}
.h3 {
margin: 1.38rem 0;
font-size: 1.424rem;
}

#tip-calculator {
width: 80%;
max-width: 350px;
padding: 1rem;
background: white;
border-radius: 0.3rem;

}

#output {
text-align: center;
box-shadow: 0 0 20px rgba(0,139,253,0.25);
padding: 10px;
color: rgb(9, 73, 171);
}

form {
border-top: 1px solid hsl(149, 31%, 25%);
}

label {
display: block;
}

input[type="number"] {
width: 100%;
max-width: 4em;
background: none;
border: none;
font-size: 20px;
color: rgb(26, 64, 237);
border-bottom: 1px dashed black;

/* Hide spinners and steppers - Firefox */
-moz-appearance: textfield;
}

/* Hide spinners and steppers - Chrome, Safari, Edge, Opera */
input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
-webkit-appearance: none;
margin: 0;
}

#people {
max-width: 3em;
}

#percentage {
-webkit-appearance: none;
width: 100%;
margin: 2rem 0;
height: 10px;
background: hsl(193, 94%, 34%);
border-radius: 3px;
}

#percentage::-webkit-slider-thumb {
-webkit-appearance: none;
appearance: none;
width: 30px;
height: 30px;
border-radius: 50%;
border: 2px solid rgb(5, 47, 156);
background: hsl(255, 14%, 66%);
cursor: pointer;
}

#percentage::-moz-range-thumb {
width: 20px;
height: 20px;
background: hsl(149, 31%, 98%);
border-radius: 50%;
cursor: pointer;
}

  </style>
</head>
<body>
  <div id="tip-calculator">
  	<h1>Tip Calculator</h1>

  	<form id="form">
  		<label for="bill" class="h3">
  			Bill: $
  			<input type="number" min="0" step="0.01" value="50" name="bill" id="bill" />
  		</label>
  		<label for="people" class="h3">
  			People:
  			<input type="number" min="1" step="1" value="1" name="people" id="people" />
  		</label>
  		<label for="percentage" class="h3">
  			Tip Percentage:
  			<span id="percentage-output"></span>
  			<input type="range" min="0" max="100" step="1" value="20" name="percentage" id="percentage" />
  		</label>
  	</form>
  	<div id="output" class="h3"></div>
  </div>

  <script type="text/javascript">
  // cached elements ==========
  const form = document.getElementById("form");
  const totalBill = document.getElementById("bill");
  const totalPeople = document.getElementById("people");
  const tipPercentage = document.getElementById("percentage");
  const percentageOutput = document.getElementById("percentage-output");
  const output = document.getElementById("output");

  // event listeners ==========
  form.addEventListener("change", calculateTip);
  tipPercentage.oninput = calculateTip;

  // event handlers ==========
  function calculateTip() {
  	const dollarsPerPerson = (
  		(totalBill.value * (tipPercentage.value / 100)) /
  		totalPeople.value
  	).toFixed(2);

  	displayTip(`$${dollarsPerPerson}`);
  	displayPercentage();
  }

  // helper functions ==========
  function displayTip(totalPerPerson) {
  	output.innerText =
  		totalPeople.value > 1
  			? `Each person should tip ${totalPerPerson}`
  			: `You should tip ${totalPerPerson}`;
  }

  function displayPercentage() {
  	percentageOutput.innerText = `${tipPercentage.value}%`;
  }

  // on load ==========
  calculateTip();

  </script>
</body>
</html>
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