吸顶交互

要求

浏览器在上下滚动的过程中，如果距离顶部的滚动距离大于78px，吸顶导航显示，小于78px隐藏

步骤：

准备吸顶导航组件

<script setup></script>

<template>
  <div class="app-header-sticky show">
    <div class="container">
      <RouterLink class="logo" to="/" />
      <!-- 导航区域 -->
      <ul class="app-header-nav">
        <li class="home">
          <RouterLink to="/">首页</RouterLink>
        </li>
        <li>
          <RouterLink to="/">居家</RouterLink>
        </li>
        <li>
          <RouterLink to="/">美食</RouterLink>
        </li>
        <li>
          <RouterLink to="/">服饰</RouterLink>
        </li>
        <li>
          <RouterLink to="/">母婴</RouterLink>
        </li>
        <li>
          <RouterLink to="/">个护</RouterLink>
        </li>
        <li>
          <RouterLink to="/">严选</RouterLink>
        </li>
        <li>
          <RouterLink to="/">数码</RouterLink>
        </li>
        <li>
          <RouterLink to="/">运动</RouterLink>
        </li>
        <li>
          <RouterLink to="/">杂项</RouterLink>
        </li>
      </ul>

      <div class="right">
        <RouterLink to="/">品牌</RouterLink>
        <RouterLink to="/">专题</RouterLink>
      </div>
    </div>
  </div>
</template>

<style scoped lang="scss">
.app-header-sticky {
  width: 100%;
  height: 80px;
  position: fixed;
  left: 0;
  top: 0;
  z-index: 999;
  background-color: #fff;
  border-bottom: 1px solid #e4e4e4;
  // 此处为关键样式!!!
  // 状态一：往上平移自身高度 + 完全透明
  transform: translateY(-100%);
  opacity: 0; // 透明

  // 状态二：移除平移 + 完全不透明
  &.show {
    transition: all 0.3s linear;
    transform: none;
    opacity: 1; // 不透明
  }

  .container {
    display: flex;
    align-items: center;
  }

  .logo {
    width: 200px;
    height: 80px;
    background: url('@/assets/images/logo.png') no-repeat right 2px;
    background-size: 160px auto;
  }

  .right {
    width: 220px;
    display: flex;
    text-align: center;
    padding-left: 40px;
    border-left: 2px solid $xtxColor;

    a {
      width: 38px;
      margin-right: 40px;
      font-size: 16px;
      line-height: 1;

      &:hover {
        color: $xtxColor;
      }
    }
  }
}

.app-header-nav {
  width: 820px;
  display: flex;
  padding-left: 40px;
  position: relative;
  z-index: 998;

  li {
    margin-right: 40px;
    width: 38px;
    text-align: center;

    a {
      font-size: 16px;
      line-height: 32px;
      height: 32px;
      display: inline-block;

      &:hover {
        color: $xtxColor;
        border-bottom: 1px solid $xtxColor;
      }
    }

    .active {
      color: $xtxColor;
      border-bottom: 1px solid $xtxColor;
    }
  }
}
</style>