.loading {
    position: absolute;
    left: 0;
    right: 0;
    top: 50%;
    width: 300px;
    color: #FFF;
    margin: auto;
    -webkit-transform: translateY(-50%);
    -moz-transform: translateY(-50%);
    -o-transform: translateY(-50%);
    transform: translateY(-50%);
}
.loading span {
    position: absolute;
    height: 10px;
    width: 84px;
    top: 50px;
    overflow: hidden;
}
.loading span > i {
    position: absolute;
    height: 4px;
    width: 4px;
    border-radius: 50%;
    -webkit-animation: wait 4s infinite;
    -moz-animation: wait 4s infinite;
    -o-animation: wait 4s infinite;
    animation: wait 4s infinite;
}
.loading span > i:nth-of-type(1) {
    left: -28px;
    background: yellow;
}
.loading span > i:nth-of-type(2) {
    left: -21px;
    -webkit-animation-delay: 0.8s;
    animation-delay: 0.8s;
    background: lightgreen;
}

@-webkit-keyframes wait {
    0%   { left: -7px  }
    30%  { left: 52px  }
    60%  { left: 22px  }
    100% { left: 100px }
}
@-moz-keyframes wait {
    0%   { left: -7px  }
    30%  { left: 52px  }
    60%  { left: 22px  }
    100% { left: 100px }
}
@-o-keyframes wait {
    0%   { left: -7px  }
    30%  { left: 52px  }
    60%  { left: 22px  }
    100% { left: 100px }
}
@keyframes wait {
    0%   { left: -7px  }
    30%  { left: 52px  }
    60%  { left: 22px  }
    100% { left: 100px }
}