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                <!-- スライダーのコンテナ -->
<div class="swiper">
  <!-- 必要に応じたwrapper -->
  <div class="swiper-wrapper">
    <!-- スライド -->
    <div class="swiper-slide">Slide 1</div>
    <div class="swiper-slide">Slide 2</div>
    <div class="swiper-slide">Slide 3</div>
  <div class="swiper-button-next"></div>
  <div class="swiper-button-prev"></div>



                .swiper--wrapper {
  /* wrapperのサイズを調整 */
  width: 100%;
  height: 100px;

.swiper-slide {
  /* スライドのサイズを調整、中身のテキスト配置調整、背景色 */
  color: #ffffff;
  width: 100%;
  height: 100%;
  text-align: center;
  line-height: 100px;

.swiper-slide:nth-child(3n + 1) {
  /*1、4、7、3n+1枚目の背景色 */
  background-color: #de4439;

.swiper-slide:nth-child(3n + 2) {
  /*2、5、8、3n+2枚目の背景色 */
  background-color: #fcd500;

.swiper-slide:nth-child(3n + 3) {
  /*3、6、9、3n+3枚目の背景色 */
  background-color: #53c638;


                const swiper = new Swiper(".swiper", {
    navigation: {
      nextEl: ".swiper-button-next",
      prevEl: ".swiper-button-prev",
    on: {
    // スライドの切り替わりアニメーションが終了した時に実行
      slideChangeTransitionEnd: function() {
        const swiperPageNum = document.querySelector('p span');
        swiperPageNum.textContent = this.realIndex + 1;