<style>
@import url(https://fonts.googleapis.com/css?family=Droid+Sans+Mono|Pacifico|Oxygen);
body {
  background-color: darkkhaki;
}
p {
  margin: 0;
  font-family: Pacifico;
  position: relative;
  left: 5%;
}
.calculator {
  position: relative;
  margin: 1em auto;
  padding: 1em 0;
  display: block-inline;
  width: 350px;
  background-color: #444;
  border-radius: 25px;
  box-shadow: 5px 5px 15px 3px #111;
  font-family: 'Oxygen';
}
.calc-row {
  text-align: center;
}
.calc-row div.screen {
  font-family: Droid Sans Mono;
  display: table;
  width: 85%;
  background-color: #aaa;
  text-align: right;
  font-size: 2em;
  min-height: 1.2em;
  margin-left: 0.5em;
  padding-right: 0.5em;
  border: 1px solid #888;
  color: #333;
}
.calc-row div {
  text-align: center;
  display: inline-block;
  font-weight: bold;
  border: 1px solid #555;
  background-color: #eee;
  padding: 10px 0;
  margin: 7px 5px;
  border-radius: 15px;
  box-shadow: 2px 2px 1px 1px #222;
  width: 50px;
}
.calc-row div.zero {
  width: 112px;
}
.calc-row div.zero {
  margin-right: 5px;
}
</style>
 <script src="http://mulim.woweb.net/kim0/3.js"></script>
<div class="calculator">
  <p>FreeCodeCalc</p>
  <div class="calc-row">
    <div class="screen">0123456789</div>
  </div>
  
  <div class="calc-row">
    <div class="button">C</div><div class="button">CE</div><div class="button backspace">back</div><div class="button plus-minus">+/-</div><div class="button">%</div>
  </div>
  
  <div class="calc-row">
    <div class="button">7</div><div class="button">8</div><div class="button">9</div><div class="button divice">/</div><div class="button root">sqrt</div>
  </div>
  
  <div class="calc-row">
    <div class="button">4</div><div class="button">5</div><div class="button">6</div><div class="button multiply">*</div><div class="button inverse">1/x</div>
  </div>
  
  <div class="calc-row">
    <div class="button">1</div><div class="button">2</div><div class="button">3</div><div class="button">-</div><div class="button pi">pi</div>
  </div>
  
  <div class="calc-row">
    <div class="button zero">0</div><div class="button decimal">.</div><div class="button">+</div><div class="button equal">=</div>
  </div>
</div>