<ul uk-accordion="multiple: true">
  <li>
    <a class="uk-accordion-title" href="#">項目1</a>
    <div class="uk-accordion-content">項目1の中身です。</div>
  </li>
  <li>
    <a class="uk-accordion-title" href="#">項目2</a>
    <div class="uk-accordion-content">項目2の中身です。</div>
  </li>
  <li>
    <a class="uk-accordion-title" href="#">項目3</a>
    <div class="uk-accordion-content">項目3の中身です。</div>
  </li>
</ul>
ul {
  li {
    .uk-accordion-title {
      position: relative;
      
      &::before {
        background-image: none;
        content: "";
        background-color: red;
        width: 14px;
        height: 2px;
        position: absolute;
        top: 50%;
        transform:translateY(-50%);
        right: 40px;
      }
      
      &::after {
        content: "";
        background-color: red;
        width: 2px;
        height: 14px;
        position: absolute;
        top: 50%;
        transform:translate(50%,-50%);
        right: 47px;
      }
    }
  }
}

.uk-open {
  >.uk-accordion-title {
    &::before {
      background-image: none;
    }
    &::after {
      content: none;
    }
  }
}
View Compiled

External CSS

  1. https://cdn.jsdelivr.net/npm/uikit@3.16.13/dist/css/uikit.min.css

External JavaScript

  1. https://cdn.jsdelivr.net/npm/uikit@3.16.13/dist/js/uikit.min.js
  2. https://cdn.jsdelivr.net/npm/uikit@3.16.13/dist/js/uikit-icons.min.js