CSS 进度条

.banner-swiper .swiper-pagination-bullet{position:relative;background-color: #888;cursor: pointer;margin: 0 25px 0 0!important;width: 60px;height: 4px;opacity: .6;border-radius:0px;}
.banner-swiper .swiper-pagination-bullet::before{content: "";position: absolute;top: 0;left: 0;width: 0;height: 100%;}
.banner-swiper .swiper-pagination-bullet-active::before{content: '';background-color: #fff;animation: tiao 3s linear 0s;animation-delay:0s;animation-fill-mode: forwards;}

@keyframes tiao {   
    0% {
    width: 0%;
    }
    100% {
    width: 100%;
    }
}