在flex DIV中居中底部定位按钮

.container {
  display: flex;
  flex-direction: column;
}

.button-container {
  flex-grow: 1;
}

.button-container {
  display: flex;
  align-items: flex-end;
}

.button {
  margin: auto;
}

<div class="container">
  <div class="content">
    <!-- 这里是页面内容 -->
  </div>
  <div class="button-container">
    <button class="button">按钮</button>
  </div>
</div>

.container {
  display: flex;
  flex-direction: column;
}

.button-container {
  display: flex;
  align-items: flex-end;
  flex-grow: 1;
}

.button {
  margin: auto;
}