CSS选择器步进箭头

Question

从第1阶段到第5阶段，我有一个带向右箭头的步进器。 当我将鼠标移到当前阶段时，我想更改当前阶段的上一个和下一个箭头的颜色。
第一个问题是我不知道如何使用css选择器获取箭头（伪元素），并使其与span元素同时更改颜色。 第二个问题是当前阶段的箭头为红色，下一个箭头不能形成平行四边形。.看起来不太好

.steps {
  padding-left: 0;
  list-style: none;
  font-size: 13px;
  line-height: 1;
  margin: 0px auto;
  border-radius: 3px;
}

.steps strong {
  font-size: 14px;
  display: block;
  line-height: 1.3;
}

.steps>li {
  position: relative;
  display: block;
  /* border: 1px solid #ddd; */
  padding: 12px 20px 8px 50px;
  width: 20%;
  height: 58px;
}

@media (min-width: 768px) {
  .steps>li {
    float: left;
  }
  .steps .past {
    color: #777;
    background: #f4f4f4;
  }
  .steps .present {
    color: #fff;
    background-color: #c32611;
  }
  .steps .future {
    color: #777;
    background: #f4f4f4;
  }
  .steps strong {}
  .steps li>span:after,
  .steps li>span:before {
    content: "";
    display: block;
    width: 0px;
    height: 0px;
    position: absolute;
    top: 0;
    left: 0;
    border: solid transparent;
    border-left-color: #f0f0f0;
    border-width: 29px 30px;
  }
  .steps li>span:after {
    top: -5px;
    z-index: 1;
    border-left-color: white;
    border-width: 34px;
  }
  .steps li>span:before {
    z-index: 2;
  }
  .steps li.past+li>span:before {
    border-left-color: #f4f4f4;
  }
  .steps li.present+li>span:before {
    border-left-color: #c32611;
  }
  .steps li.future+li>span:before {
    border-left-color: #f4f4f4;
  }
  .steps li:first-child>span:after,
  .steps li:first-child>span:before {
    display: none;
  }
  /* Arrows at start and end */
  .steps li:first-child i,
  .steps li:last-child i {
    display: block;
    position: absolute;
    top: 0;
    left: 0;
    border: solid transparent;
    border-left-color: white;
    border-width: 30px;
  }
  .steps li:last-child i {
    left: auto;
    right: -30px;
    border-left-color: transparent;
    border-top-color: white;
    border-bottom-color: white;
  }

  <ul class="steps">
    <!--past present future-->
    <li class="past" onMouseOver="this.style.background='#e3e3e3'" onMouseOut="this.style.background='transparent'" style="cursor: pointer;">
      <span wicket:id="stage31"><strong>Stage 1</strong>Start</span><i></i></li>
    <li class="past" onMouseOver="this.style.background='#e3e3e3'" onMouseOut="this.style.background='transparent'" style="cursor: pointer;">
      <span wicket:id="stage32"><strong>Stage 2</strong>This is stage 2</span><i></i></li>
    <li class="present"><span><strong>Stage 3</strong>This is stage 3</span><i></i></li>
    <li class="future" onMouseOver="this.style.background='#e3e3e3'" onMouseOut="this.style.background='transparent'" style="cursor: pointer;">
      <span wicket:id="stage34"><strong>Stage 4</strong>This is stage 4</span><i></i></li>
    <li class="future"><span><strong>Stage 5</strong>Finish</span><i></i></li>
  </ul>