有没有一种方法可以将左箭头放在div上方？

Question

我在一个div内有两个div，宽度为100％。一格的宽度为70％，另一格的宽度为30％。我正在尝试做的是当链接处于活动状态时30％的div具有向左箭头**。

在这里您可以看到一些有关我的代码以及设计所在位置的图像。

.menu a.active:before {
  content: "";
  position: absolute;
  top: 50%;
  left: -21px;
  z-index: -1;
  height: 30px;
  width: 30px;
  margin-top: -15px;
  background: #FFF;
  transform: rotate(45deg);
  -ms-transform: rotate(45deg);
  -webkit-transform: rotate(45deg);
  border-opacity: 0.3;
  border-left: 5px solid rgba(0, 0, 0, .3);
  border-bottom: 5px solid rgba(0, 0, 0, .3);
  -webkit-background-clip: padding-box;
  /* for Safari */
  background-clip: padding-box;
  /* for IE9+, Firefox 4+, Opera, Chrome */
}

.menu a.active {
  position: relative;
  background: #FFF;
  -webkit-border-radius: 10px;
  -moz-border-radius: 10px;
  border-radius: 10px;
  /* width: 250px; */
  /* height: 250px; */
  /* padding:5px; */
  z-index: 1;
  border-opacity: 0.3;
  /* border: 5px solid rgba(0, 0, 0, .3); */
  -webkit-background-clip: padding-box;
  /* for Safari */
  background-clip: padding-box;
  /* for IE9+, Firefox 4+, Opera, Chrome */
}

<div id="featured">
  <!--div with width 70%-->
  <div class="fragments-together ">
    <div class="slider">
      <div class="box  overlay-image-up">
        <span class="top-title">Upcoming events</span>
        <span>
          <img class="slider-homepage" src="./img/slider-home-page.png"/>
        </span>
        <div class="info">
          <div class="info-left">
            <span>17 January 2020</span>
            <h1>European youth gathered in Buzau at the end of the year</h1>
          </div>
          <div class="info-right">
            <button>see more</button>
          </div>
        </div>
      </div>
      <div class="box  overlay-image-up">
        <span class="top-title">Upcoming events</span>
        <span>
          <img class="slider-homepage" src="./img/slider-home-page.png"/>
        </span>
        <div class="info">
          <div class="info-left">
            <span>17 January 2020</span>
            <h1>European youth gathered in Buzau at the end of the year</h1>
          </div>
          <div class="info-right">
            <button>see more</button>
          </div>
        </div>
      </div>
      <div class="box  overlay-image-up">
        <span class="top-title">Upcoming events</span>
        <span>
          <img class="slider-homepage" src="./img/slider-home-page.png"/>
        </span>
        <div class="info">
          <div class="info-left">
            <span>17 January 2020</span>
            <h1>European youth gathered in Buzau at the end of the year</h1>
          </div>
          <div class="info-right">
            <button>see more</button>
          </div>
        </div>
      </div>
      <div class="box  overlay-image-up">
        <span class="top-title">Upcoming events</span>
        <span>
          <img class="slider-homepage" src="./img/slider-home-page.png"/>
        </span>
        <div class="info">
          <div class="info-left">
            <span>17 January 2020</span>
            <h1>European youth gathered in Buzau at the end of the year</h1>
          </div>
          <div class="info-right">
            <button>see more</button>
          </div>
        </div>
      </div>
    </div>
    <div class="overlay-slider"></div>
  </div>
  <ul class="ui-tabs-nav">
    <div class="menu">
      <a href="#" data-picindex="1">
        <span><img src="./img/cube-icon.png" alt="">21 Feb 2019</span>
        <h2>Lorem ipsum dolor sit amet consectetur adipiscing elit, sed do eiusmod </h2>
      </a>
      <a href="#" data-picindex="2">
        <span><img src="./img/cube-icon.png" alt="">21 Feb 2019</span>
        <h2>European youth gathered in Buzau at the end of the year</h2>
      </a>
      <a href="#" data-picindex="3">
        <span><img src="./img/cube-icon.png" alt="">21 Feb 2019</span>
        <h2>Lorem ipsum dolor sit amet consectetur adipiscing elit, sed do eiusmod </h2>
      </a>
      <a href="#" data-picindex="4">
        <span><img src="./img/cube-icon.png" alt="">21 Feb 2019</span>
        <h2>Lorem ipsum dolor sit amet consectetur adipiscing elit, sed do eiusmod </h2>
      </a>
    </div>
  </ul>
</div>

我可以在div中添加箭头吗？我正在使用滑块，这是一个滑块。

谢谢您的时间！