slick-change-dots.custom.css

selector .slick-dots li button {
    box-shadow: inset 0 0 0 8px #000;
    border-radius: 50%;
    border:1px solid #000;
}

selector .slick-dots li button:hover {
    box-shadow: inset 0 0 0 8px #fff;
    border-radius: 50%;
}

selector .slick-dots li.slick-active button {
    box-shadow: inset 0 0 0 8px #fff;
}