<form class="calc">  
  <p class="calc-display">  
  <input type="text" name="res" id="res" value="4815.1623" class="calc-display-input" onfocus="this.blur()">  
  </p>  
  <p class="calc-row">  
  <button type="button" class="calc-button calc-button-gray" onclick="s('Just....')">mrc</button>  
  <button type="button" class="calc-button calc-button-gray" onclick="s('....do..')">m-</button>  
  <button type="button" class="calc-button calc-button-gray" onclick="s('......it')">m+</button>  
  <button type="button" class="calc-button calc-button-red calc-button-big" onclick="a('/')">÷</button>  
  </p>  
  <p class="calc-row">  
  <button type="button" class="calc-button" onclick="a('7')">7</button>  
  <button type="button" class="calc-button" onclick="a('8')">8</button>  
  <button type="button" class="calc-button" onclick="a('9')">9</button>  
  <button type="button" class="calc-button calc-button-red calc-button-big" onclick="a('*')">x</button>  
  </p>  
  <p class="calc-row">  
  <button type="button" class="calc-button" onclick="a('4')">4</button>  
  <button type="button" class="calc-button" onclick="a('5')">5</button>  
  <button type="button" class="calc-button" onclick="a('6')">6</button>  
  <button type="button" class="calc-button calc-button-red calc-button-big" onclick="a('-')">-</button>  
  </p>  
  <p class="calc-row">  
  <button type="button" class="calc-button" onclick="a('1')">1</button>  
  <button type="button" class="calc-button" onclick="a('2')">2</button>  
  <button type="button" class="calc-button" onclick="a('3')">3</button>  
  <button type="button" class="calc-button calc-button-red calc-button-big" onclick="a('+')">+</button>  
  </p>  
  <p class="calc-row">  
  <button type="button" class="calc-button" onclick="a('0')">0</button>  
  <button type="button" class="calc-button" onclick="a('.')">.</button>  
  <button type="button" class="calc-button" onclick="s('')">C</button>  
  <button type="button" class="calc-button calc-button-yellow calc-button-big" onclick="e()">=</button>  
  </p>  
  </form>  

  <script>  
  function s(v) { document.getElementById('res').value = v }  
  function a(v) { document.getElementById('res').value += v }  
  function e() { try { s(eval(document.getElementById('res').value)) } catch(e) { s('Error') } }  
  </script>

.calc {  
  margin: 50px auto;  
  padding: 15px;  
  width: 177px;  
  border: 1px solid #222;  
  border-radius: 4px;  
  background-color: #3d4543;  
  background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0%, #3d4543), color-stop(100%, #2f2a2f));  
  background-image: -webkit-linear-gradient(top, #3d4543, #2f2a2f);  
  background-image: -moz-linear-gradient(top, #3d4543, #2f2a2f);  
  background-image: -ms-linear-gradient(top, #3d4543, #2f2a2f);  
  background-image: -o-linear-gradient(top, #3d4543, #2f2a2f);  
  background-image: linear-gradient(top, #3d4543, #2f2a2f);  
  -webkit-box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.1), 0 0 4px rgba(0, 0, 0, 0.5);  
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.1), 0 0 4px rgba(0, 0, 0, 0.5);  
}  

.calc-display {  
  margin: 0 0 20px;  
  padding: 3px;  
  background: #222;  
  border-radius: 3px;  
  -webkit-box-shadow: inset 0 0 0 1px rgba(0, 0, 0, 0.1), 0 0 0 1px rgba(255, 255, 255, 0.08);  
  box-shadow: inset 0 0 0 1px rgba(0, 0, 0, 0.1), 0 0 0 1px rgba(255, 255, 255, 0.08);  
}  

.calc-display-input {  
  display: block;  
  width: 100%;  
  padding: 0 8px;  
  font: 26px/35px UbuntuMono, monospace;  
  color: #444;  
  height: 35px;  
  text-align: right;  
  background-clip: padding-box;  
  /* Don't let the background bleed outside the border */  
  border: 1px solid #222;  
  border-radius: 2px;  
  background-color: #bccd95;  
  background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0%, #bccd95), color-stop(100%, #e0f5b1));  
  background-image: -webkit-linear-gradient(top, #bccd95, #e0f5b1);  
  background-image: -moz-linear-gradient(top, #bccd95, #e0f5b1);  
  background-image: -ms-linear-gradient(top, #bccd95, #e0f5b1);  
  background-image: -o-linear-gradient(top, #bccd95, #e0f5b1);  
  background-image: linear-gradient(top, #bccd95, #e0f5b1);  
  -webkit-box-shadow: inset 0 2px 3px rgba(0, 0, 0, 0.5), 0 0 0 1px rgba(255, 255, 255, 0.12);  
  box-shadow: inset 0 2px 3px rgba(0, 0, 0, 0.5), 0 0 0 1px rgba(255, 255, 255, 0.12);  
}  

.calc-row {  
  margin-top: 7px;  
  zoom: 1;  
}  
.calc-row:before, .calc-row:after {  
  content: "";  
  display: table;  
}  
.calc-row:after {  
  clear: both;  
}  

.calc-button {  
  float: left;  
  padding: 0;  
  margin: 0 0 0 7px;  
  width: 39px;  
  font: 14px/23px UbuntuMono, monospace;  
  color: white;  
  text-align: center;  
  text-shadow: 0 1px rgba(0, 0, 0, 0.4);  
  text-decoration: none;  
  background-clip: padding-box !important;  
  /* !important because FF overrides the value on :active */  
  border: 0;  
  /* IE 8 fix */  
  border: 1px solid rgba(0, 0, 0, 0.8);  
  border-radius: 3px;  
  cursor: pointer;  
  background-color: #313131;  
  background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0%, #313131), color-stop(100%, #1c1c1c));  
  background-image: -webkit-linear-gradient(top, #313131, #1c1c1c);  
  background-image: -moz-linear-gradient(top, #313131, #1c1c1c);  
  background-image: -ms-linear-gradient(top, #313131, #1c1c1c);  
  background-image: -o-linear-gradient(top, #313131, #1c1c1c);  
  background-image: linear-gradient(top, #313131, #1c1c1c);  
  -webkit-box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.08), 0 1px rgba(0, 0, 0, 0.3), 0 0 0 1px rgba(255, 255, 255, 0.08);  
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.08), 0 1px rgba(0, 0, 0, 0.3), 0 0 0 1px rgba(255, 255, 255, 0.08);  
}  
.calc-button:first-child {  
  margin-left: 0;  
}  
.calc-button:active {  
  background: #282828;  
  -webkit-box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.6), 0 1px rgba(0, 0, 0, 0.1), 0 0 0 1px rgba(255, 255, 255, 0.05);  
  box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.6), 0 1px rgba(0, 0, 0, 0.1), 0 0 0 1px rgba(255, 255, 255, 0.05);  
}  

.calc-button-gray {  
  background-color: #6f6f6f;  
  background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0%, #6f6f6f), color-stop(100%, #515151));  
  background-image: -webkit-linear-gradient(top, #6f6f6f, #515151);  
  background-image: -moz-linear-gradient(top, #6f6f6f, #515151);  
  background-image: -ms-linear-gradient(top, #6f6f6f, #515151);  
  background-image: -o-linear-gradient(top, #6f6f6f, #515151);  
  background-image: linear-gradient(top, #6f6f6f, #515151);  
}  
.calc-button-gray:active {  
  background: #555;  
}  

.calc-button-red {  
  background-color: #ff4561;  
  background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0%, #ff7286), color-stop(100%, #ff4561));  
  background-image: -webkit-linear-gradient(top, #ff7286, #ff4561);  
  background-image: -moz-linear-gradient(top, #ff7286, #ff4561);  
  background-image: -ms-linear-gradient(top, #ff7286, #ff4561);  
  background-image: -o-linear-gradient(top, #ff7286, #ff4561);  
  background-image: linear-gradient(top, #ff7286, #ff4561);  
}  
.calc-button-red:active {  
  background: #ff4561;  
}  

.calc-button-yellow {  
  background-color: #ffa70c;  
  background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0%, #ffb935), color-stop(100%, #ffa70c));  
  background-image: -webkit-linear-gradient(top, #ffb935, #ffa70c);  
  background-image: -moz-linear-gradient(top, #ffb935, #ffa70c);  
  background-image: -ms-linear-gradient(top, #ffb935, #ffa70c);  
  background-image: -o-linear-gradient(top, #ffb935, #ffa70c);  
  background-image: linear-gradient(top, #ffb935, #ffa70c);  
}  
.calc-button-yellow:active {  
  background: #ffa70c;  
}  

.calc-button-big {  
  font-size: 16px;  
}