swiper轮播图缩略图效果彩色到黑白的变化的解决方案

#thumbs .swiper-slide {
    opacity: 0.6;
    width: 25%;
    height: 40px;
    margin: auto 30px;
    cursor: pointer;
    filter: grayscale(100%);
}

#thumbs .swiper-slide-thumb-active {
    opacity: 1;
    filter: grayscale(0);
}

Done!