how to change swiper-button-prev and next color with swiper in Ruby on rails 7?

Question

I want to change swiper-button-prev and next color with swiper in Ruby on rails 7

My html code

            <swiper-container navigation="true" pagination="true" scrollbar="true" effect="coverflow" loop="true">
                <swiper-slide>
                    <div class="mpla">Slide 1 </div>
                </swiper-slide>
                <swiper-slide>
                    <div class="mpla">Slide 2 </div>
                </swiper-slide>
                <swiper-slide>
                    <div class="mpla">slide 3 </div>
                </swiper-slide>
                <swiper-slide>
                    <div class="mpla">Slide 4 </div>
                </swiper-slide>


            </swiper-container>

My css code that is not working

.swiper-button-prev,
.swiper-button-next {
  color: #330023;
}