css3向外发射的动画

html

<div class="single">
    <div class="single_center"></div>
</div>

css

body{ background: #59d1b6;}
.single_center {
    width: 20px;
    height: 20px;
    margin: 300px auto;
    border-radius: 100%;
    background: #fff;
    cursor: pointer;
    display: block;
    position: relative;
}
.single_center:after {
    content: '';
    position: absolute;
    width: 120px;
    height: 120px;
    border-radius: 100%;
    background: rgba(255, 255, 255, 0.5);
    top: 50%;
    left: 50%;
    margin-top: -60px;
    margin-left: -60px;
    z-index: 4;
    opacity: 0;
    -webkit-animation: halo 2s 1.5s infinite ease;
    -moz-animation: halo 2s 1.5s infinite ease;
    animation: halo 2s 1.5s infinite ease;
}
.single_center:before {
    content: '';
    position: absolute;
    width: 160px;
    height: 160px;
    border-radius: 100%;
    background: rgba(255, 255, 255, 0.3);
    top: 50%;
    left: 50%;
    margin-top: -80px;
    margin-left: -80px;
    z-index: 3;
    opacity: 0;
    -webkit-animation: halos 2s 1s infinite ease;
    -moz-animation: halos 2s 1s infinite ease;
    animation: halos 2s 1s infinite ease;
}

@-webkit-keyframes halos {
    0% {opacity: 0;-webkit-transform: scale(0.3);}
    50% {opacity: 1;}
    100% {opacity: 0;-webkit-transform: scale(1.2);}
}
@-moz-keyframes halos {
    0% {opacity: 0;-moz-transform: scale(0.1);}
    50% {opacity: 1;}
    100% {opacity: 0;-moz-transform: scale(1.2);}
}
@-ms-keyframes halos{
    0%{opacity:0}
    50%{opacity:1}
    100%{opacity:0}
}
@-o-keyframes halos{
    0%{opacity:0;-o-transform:scale(0.1)}
    50%{opacity:1}
    100%{opacity:0;-o-transform:scale(1.2)}
}
@keyframes halos{
    0%{opacity:0;transform:scale(0.1)}
    50%{opacity:1}
    100%{opacity:0;transform:scale(1.2)}
}

@-webkit-keyframes halo {
    0% {opacity: 0;-webkit-transform: scale(0.1);}
    50% {opacity: 1;}
    100% {opacity: 0;-webkit-transform: scale(1.2);}
}
@-moz-keyframes halo {
    0% {opacity: 0;-moz-transform: scale(0.1);}
    50% {opacity: 1;}
    100% {opacity: 0;-moz-transform: scale(1.2);}
}
@-ms-keyframes halo{
    0%{opacity:0}
    50%{opacity:1}
    100%{opacity:0}
}
@-o-keyframes halo{
    0%{opacity:0;-o-transform:scale(0.1)}
    50%{opacity:1}
    100%{opacity:0;-o-transform:scale(1.2)}
}
@keyframes halo{
    0%{opacity:0;transform:scale(0.1)}
    50%{opacity:1}
    100%{opacity:0;transform:scale(1.2)}
}

效果图