index.slim

#loading
  /! shadow
  .outer-shadow
  /! mask
  .inner-shadow
  .load
    .dot
      span
    #left.hold
      .pie
    #right.hold
      .pie

style.css

html{
  height:100%;
  background:#dde6f0;
}

#loading {
  width: 200px;
  height: 200px;
  margin: 30px auto;
  position: relative;
}

.outer-shadow, .inner-shadow, .load {
  position: absolute;
  width: 100%;
  height: 100%;
  border-radius: 100%;
}

.outer-shadow {
  z-index: 3;
  box-shadow: inset 0 1px 3px rgba(0, 0, 0, .4);
}

.inner-shadow {
  z-index: 2;
  top: 50%;
  left: 50%;
  width: 160px;
  height: 160px;
  margin: -80px 0 0 -80px;
  background-color: #dde6f0;
  box-shadow: 0 1px 3px rgba(0, 0, 0, .4);
}

.load {
  z-index: 1;
}

.hold {
  background-color: #FFF;
  position: absolute;
  width: 100%;
  height: 100%;
  clip: rect(0px, 200px, 200px, 100px);
  -webkit-border-radius: 100%;
}

.pie, .dot span {
  background-color: #f50;
}

.pie {
  position: absolute;
  width: 100%;
  height: 100%;
  -webkit-border-radius: 100%;
  clip: rect(0px, 100px, 200px, 0px);
}

#left .pie {
  z-index: 1;
  -webkit-animation: login 2s linear both;
}

@-webkit-keyframes login {
  0% { -webkit-transform: rotate(0deg); }
  100% { -webkit-transform: rotate(180deg);}
}

#right {
  z-index: 3;
  -webkit-transform: rotate(180deg);
}

#right .pie {
  -webkit-animation: dosya 2s linear both;
  -webkit-animation-delay: 2s
}

@-webkit-keyframes dosya {
  0% { -webkit-transform: rotate(0deg); }
  100% { -webkit-transform: rotate(180deg);}
}

.dot {
  z-index: 2;
  position: absolute;
  left: 50%;
  top: 50%;
  width: 50%;
  height: 20px;
  margin-top: -10px;
  -webkit-animation: dot 4s linear both;
  -webkit-transform-origin: 0% 50%;
}

.dot span {
  position: absolute;
  top: 0;
  right: 0;
  width: 20px;
  height: 20px;
  border-radius: 100%;
  
}

@-webkit-keyframes dot {
  0% { -webkit-transform: rotate(-90deg); }
  50% { -webkit-transform: rotate(90deg); z-index:4;}
  100% { -webkit-transform: rotate(270deg); z-index:4;}
}