<template>
  <!-- 上下固定，中间滚动布局；兼容ios和安卓以及pc -->
  <div class="container">
    <div class="header-exp">聊天头部</div>
    <div class="topcontent">
      <div class="talk-sticky">
        <div class="topcontent-text">登录享保障，遇虚假欺诈，百度助你维权</div>
        <div class="topcontent-fixd">
          这个一个相对topcontent固定定位的设计方案
        </div>
      </div>
    </div>

    <div class="chatview">
      <div class="list" v-for="(item, index) in 20" :key="index">
        {{ index + 1 }}
      </div>
    </div>

    <!-- 注释下面就只有顶部固定 -->
    <div class="footer">
      <div class="footer-input">
        <input type="text" />
      </div>
      <div class="footer-send">发送</div>
    </div>
  </div>
</template>

<style lang="scss" scoped>
.container {
  display: flex;
  flex-direction: column;
  height: 100%;
  width: 100%;

  .header-exp {
    display: flex;
    height: 50px;
    background: blue;
  }

  .topcontent {
    background-color: #fff;
    width: 100%;
    order: 2;
    position: relative;

    &-text {
      padding: 15px;
      background: #ccc;
    }

    &-fixd {
      position: fixed;
      /* top: ;这个top不能设置才能有效 */
      left: 0;
      right: 0;
      z-index: 777;
      background: #fff;
      padding: 15px;
    }
  }

  .chatview {
    background-color: #f5f5f5;
    flex: 1;
    flex-direction: column;
    justify-content: flex-start;
    order: 4;
    overflow-x: hidden;
    overflow-y: scroll;
    overscroll-behavior: none;
    position: relative;
    scroll-behavior: smooth;

    .list {
      padding: 15px;
    }
  }

  .footer {
    order: 6;
    position: relative;
    z-index: 1000;
    padding: 10px 15px;
    display: flex;
    justify-content: space-between;
    align-items: center;

    &-input {
      flex: 1;
      overflow: hidden;

      input {
        width: 300px;
      }
    }

    &-send {
    }
  }
}
</style>