.container{
    background-color: #f5f5f5;
    position: fixed;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
}

.progressbar{
    width: 120px;
    height: 120px;
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
}

.circle-outer{
    left: 0px;
    top: 0px;
    position: absolute;
    width: 120px;
    height: 120px;
}

.circle-outer .left{
    left: 0px;
    top: 0px;
    position: absolute;
    width: 120px;
    height: 120px;
    border-radius: 50%;
    clip: rect(0, 60px, 120px, 0);
    box-shadow: 0 0 0 3px dodgerblue inset;
    animation: anim-rotate-circle-outer 1s linear infinite;
}

.circle-outer .right{
    left: 0px;
    top: 0px;
    position: absolute;
    width: 120px;
    height: 120px;
    border-radius: 50%;
    clip: rect(60px, 120px, 120px, 60px);
    box-shadow: 0 0 0 3px dodgerblue inset;
    animation: anim-rotate-circle-outer 1s linear infinite;
}


@keyframes anim-rotate-circle-outer{

    0% {
        transform: rotate(0deg);
    }

    100%{
        transform: rotate(360deg);
    }

}

/*
    下面这部分模仿了网上案例
*/
.circle-inner{
    position: relative;
}

.circle-inner-main {
    position: relative;
    display:inline-block;
    height: 70px;
    width: 70px;
    border-radius: 50%;  
    background-color: #59ACFF;
    overflow:hidden;
}

.circle-inner-main:after {
    position: absolute;
    top: 9px; left: 9px;
    display: block;
    height: 28px; width: 28px;
    background-color: dodgerblue;
    border-radius: 50%;
}
.circle-inner-main > div {
    position: absolute;
    height: 100%; width: 50%;
    overflow: hidden;
}

.circle-inner-main .left  { left:0   }

.circle-inner-main .right { left:50% }

.anim {
    position: absolute;
    left: 100%; top: 0;
    height: 100%; width: 100%;
    border-radius: 999px;
    background-color: dodgerblue;
    animation: anim-rotate-circle-inner-left 2s infinite;
    transform-origin: 0 50% 0;
}

.left .anim {
    animation-delay: 0s;
    animation-duration:2s;
    animation-timing-function: linear;
    border-bottom-left-radius: 0;
    border-top-left-radius: 0;
}
.right .anim {
    animation-duration:2s;
    animation-timing-function: linear;
    border-bottom-right-radius: 0;
    border-top-right-radius: 0;
    left: -100%;
    transform-origin: 100% 50% 0;
    animation-name: anim-rotate-circle-inner-right;
    animation-delay: 1s;
}


@keyframes anim-rotate-circle-inner-right{
  0%{transform:rotate(0deg)}
  25%{transform:rotate(180deg)}
  50%{transform:rotate(180deg)}
  75%{transform:rotate(360deg)}
  100%{transform:rotate(360deg)}
}

@keyframes anim-rotate-circle-inner-left{
  0%{transform:rotate(0deg)}
  25%{transform:rotate(0deg)}
  50%{transform:rotate(180deg)}
  75%{transform:rotate(180deg)}
  100%{transform:rotate(360deg)}
}