A Pen by Seth Abbott.

index.html

<div class="button-wrap">
  <button type="button"></button>
  <span class="typicons-key active"></span>
</div>

Pure-CSS---Lock-Screen.markdown

Pure CSS - Lock Screen

original design on dribbble.com, http://dribbble.com/shots/350018-Lock-screen?list=searches&tag=ui

A Pen by Seth Abbott on CodePen.

License.

style.css

@import url(http://weloveiconfonts.com/api/?family=typicons);

/* typicons */
[class*="typicons-"]:before {
  font-family: 'Typicons', sans-serif;
}

html {
  min-height: 100%;
  font-size: 87.5%
background: rgb(255,255,255); /* Old browsers */
background: -moz-linear-gradient(top,  rgba(255,255,255,1) 33%, rgba(224,224,224,1) 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, left bottom, color-stop(33%,rgba(255,255,255,1)), color-stop(100%,rgba(224,224,224,1))); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(top,  rgba(255,255,255,1) 33%,rgba(224,224,224,1) 100%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(top,  rgba(255,255,255,1) 33%,rgba(224,224,224,1) 100%); /* Opera 11.10+ */
background: -ms-linear-gradient(top,  rgba(255,255,255,1) 33%,rgba(224,224,224,1) 100%); /* IE10+ */
background: linear-gradient(to bottom,  rgba(255,255,255,1) 33%,rgba(224,224,224,1) 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#ffffff', endColorstr='#e0e0e0',GradientType=0 ); /* IE6-9 */

}

body {
  text-align: center;
  font-size: 1rem;
}



.button-wrap {
  position: relative;
  margin: 50px auto;
  width: 8rem;
  border: 1px solid #e5e5e5;
  height: 8rem;
  border-radius: 8rem;
  cursor: pointer;
  box-shadow: inset 0 1px 0 rgba(255,255,255,1),
              0 1px 1px rgba(0,0,0,.15);
  
background: rgb(239,239,239); /* Old browsers */
background: -moz-linear-gradient(top,  rgba(239,239,239,1) 0%, rgba(254,254,254,1) 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(239,239,239,1)), color-stop(100%,rgba(254,254,254,1))); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(top,  rgba(239,239,239,1) 0%,rgba(254,254,254,1) 100%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(top,  rgba(239,239,239,1) 0%,rgba(254,254,254,1) 100%); /* Opera 11.10+ */
background: -ms-linear-gradient(top,  rgba(239,239,239,1) 0%,rgba(254,254,254,1) 100%); /* IE10+ */
background: linear-gradient(to bottom,  rgba(239,239,239,1) 0%,rgba(254,254,254,1) 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#efefef', endColorstr='#fefefe',GradientType=0 ); /* IE6-9 */


}

button {
  position: absolute;
  left: 7.5%;
  top: 7.5%;
  width: 85%;
  height: 85%;
  border-radius: 100%;
  border: none;
  box-shadow: inset 1px 1px 20px rgba(0,0,0,.5);
  border: 1px solid #27468b;
  
  
background: rgb(40,215,255); /* Old browsers */
background: -moz-linear-gradient(top,  rgba(40,215,255,1) 19%, rgba(43,163,215,1) 52%, rgba(95,123,194,1) 90%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, left bottom, color-stop(19%,rgba(40,215,255,1)), color-stop(52%,rgba(43,163,215,1)), color-stop(90%,rgba(95,123,194,1))); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(top,  rgba(40,215,255,1) 19%,rgba(43,163,215,1) 52%,rgba(95,123,194,1) 90%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(top,  rgba(40,215,255,1) 19%,rgba(43,163,215,1) 52%,rgba(95,123,194,1) 90%); /* Opera 11.10+ */
background: -ms-linear-gradient(top,  rgba(40,215,255,1) 19%,rgba(43,163,215,1) 52%,rgba(95,123,194,1) 90%); /* IE10+ */
background: linear-gradient(to bottom,  rgba(40,215,255,1) 19%,rgba(43,163,215,1) 52%,rgba(95,123,194,1) 90%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#28d7ff', endColorstr='#5f7bc2',GradientType=0 ); /* IE6-9 */

}

.button-wrap:after {
  position: absolute;
  left: 25%;
  top: 25%;
  content: " ";
  display: block;
  background: #f5f5f5;;
  width: 50%;
  height: 50%;
  border-radius: 100%;
  box-shadow: inset 0 2px 0 rgba(255,255,255,1),
    0 5px 18px rgba(0,0,0,.7);;
}

/* typicons */
[class*="typicons-"]:before {
  position: absolute;
  display: block;
  z-index: 10;
  left: 26%;
  top: 56%;
  line-height: 0;
  font-family: 'Typicons', sans-serif;
  font-size: 65px;
  color: #e0e0e0;
  text-shadow: 0 -1px 0 rgba(0,0,0,.25);
  transform: rotate(0deg) rotateY(180deg);
  transition: all .25s ease;
  
}

.button-wrap:hover [class*="typicons-"]:before {
transform: rotate(0deg) rotateY(0deg);
}