CSS：文字水平居中的写法

<view class='kk'>
水平垂直居中文字
</view>

.kk{
  border: 1px solid #000000; 
  width: 200px; 
  height: 200px;
  margin: 0 auto;
  text-align: center;
  line-height: 200px;
}

其中line-height需要注意下。

<view class="section">
  <view class="section__title">flex-direction: row</view>
  <view class="flex-wrp" style="flex-direction:row;">
    <view class="flex-item bc_green">1</view>
    <view class="flex-item bc_red">2</view>
    <view class="flex-item bc_blue">3</view>
  </view>
</view>
<view class="section">
  <view class="section__title">flex-direction: column</view>
  <view class="flex-wrp" style="height: 300px;flex-direction:column;">
    <view class="flex-item bc_green">1</view>
    <view class="flex-item bc_red">2</view>
    <view class="flex-item bc_blue">3</view>
  </view>
</view>

.flex-wrp {
  display: flex;
}

.flex-item.bc_green {
  width: 100px;
  height: 100px;
  background-color: green;
  text-align: center;
  line-height: 100px;
}

.flex-item.bc_red {
  width: 100px;
  height: 100px;
  background-color: red;
  text-align: center;
  line-height: 100px;
}

.flex-item.bc_blue {
  width: 100px;
  height: 100px;
  background-color: blue;
  text-align: center;
  line-height: 100px;
}

 下面这种写法也是可以的：

.flex-wrp {
  display: flex;
}
.flex-item{
  display: flex;
   width: 100px;
  height: 100px;
  justify-content: center;
  align-items: center;
}

.bc_green {
  background-color: green;
}

.flex-wrp .flex-item.bc_red {
  background-color: red;
}

.flex-wrp .flex-item.bc_blue {
  background-color: blue;
}