Как убрать текст на кнопках навигации slikc slider-a?

<button type="button" data-role="none" class="slick-prev slick-arrow slick-disabled" aria-label="Previous" role="button" aria-disabled="true" style="display: block;">Previous</button>

<button type="button" data-role="none" class="slick-next slick-arrow" aria-label="Next" role="button" style="display: block;" aria-disabled="false">Next</button>

<button class="slick-prev slick-arrow" aria-label="Previous" type="button" style="display: block;">Previous</button>

.slick-arrow {
    text-indent: -9999px !important;
    color: transparent; /* опционально */
}