depends on my manila mixins or just replace the size mixin for width and height

slick-custom.scss

.slick-slider {
  margin-bottom: 40px;
}
// Custom Dots
.slick-dots {
  text-align: center;
  font-size: 0;
  line-height: 0;
  position: absolute;
  width: 100%;
  left: 0;
  bottom: -30px;
  li {
    display: inline-block;
    margin: 0 4px;
    position: relative;
    line-height: 0;
    font-size: 0;
    button {
      background: none;
      padding: 5px;
      line-height: 0;
      font-size: 0;
      width: 10px;
      height: 10px;
      &::before {
        @include size(10px);
        content: '';
        background: $white;
        position: absolute;
        top: 0;
        left: 0;
        border-radius: 50%;
        border: 1px solid $black;
      }
    }
    &.slick-active {
      button::before {
        background: $black;
      }
    }
  }
}
// Arrows
.slick-prev,
.slick-next {
  position: absolute;
  display: block;
  width: 25px;
  height: 19px;
  line-height: 0;
  font-size: 0;
  cursor: pointer;
  background: none;
  z-index: 1;
  bottom: -35px;
  padding: 0;
  border: none;
  border-radius: 0;
  outline: none;
  &:hover, &:focus {
    background: none;
  }
  &::before {
    content: '';
    display: block;
    width: 25px;
    height: 19px;
  }
}
.slick-prev {
  left: 0;
  &::before {
    background: url('../images/arrow-left--slider.png') no-repeat center / cover;
  }
}
.slick-next {
  right: 0;
  &::before {
    background: url('../images/arrow-right--slider.png') no-repeat center / cover;
  }
}