element/examples/docs/layout.md

<style>
  .demo-layout {
    .el-row {
      margin-bottom: 20px;
      &:last-child {
        margin-bottom: 0;
      }
    }
    .el-col {
      height: 36px;
      border-radius: 4px;
    }
    .bg-purple-dark {
      background: #99a9bf;
    }
    .bg-purple {
      background: #d3dce6;
    }
    .bg-purple-light {
      background: #e5e9f2;
    }
    .grid-content {
      height: 100%;
      border-radius: 4px;
    }
    .row-bg {
      padding: 10px 0;
      background-color: #f9fafc;
    }
  }
</style>

## Layout 布局

通过基础的 24 分栏，迅速简便地创建布局。

### 基础布局

使用单一分栏创建基础的栅格布局。

::: demo 通过 row 和 col 组件，并通过 col 组件的 `span` 属性我们就可以自由地组合布局。
```html
<el-row>
  <el-col :span="24"><div class="grid-content bg-purple-dark"></div></el-col>
</el-row>
<el-row>
  <el-col :span="12"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="12"><div class="grid-content bg-purple-light"></div></el-col>
</el-row>
<el-row>
  <el-col :span="8"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="8"><div class="grid-content bg-purple-light"></div></el-col>
  <el-col :span="8"><div class="grid-content bg-purple"></div></el-col>
</el-row>
<el-row>
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="6"><div class="grid-content bg-purple-light"></div></el-col>
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="6"><div class="grid-content bg-purple-light"></div></el-col>
</el-row>
<el-row>
  <el-col :span="4"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="4"><div class="grid-content bg-purple-light"></div></el-col>
  <el-col :span="4"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="4"><div class="grid-content bg-purple-light"></div></el-col>
  <el-col :span="4"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="4"><div class="grid-content bg-purple-light"></div></el-col>
</el-row>
```
:::

### 分栏间隔

分栏之间存在间隔。

::: demo Row 组件 提供 `gutter` 属性来指定每一栏之间的间隔，默认间隔为 0。
```html
<el-row :gutter="20">
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
</el-row>
```
:::

### 混合布局

通过基础的 1/24 分栏任意扩展组合形成较为复杂的混合布局。

::: demo
```html
<el-row :gutter="20">
  <el-col :span="16"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="8"><div class="grid-content bg-purple"></div></el-col>
</el-row>
<el-row :gutter="20">
  <el-col :span="8"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="8"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="4"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="4"><div class="grid-content bg-purple"></div></el-col>
</el-row>
<el-row :gutter="20">
  <el-col :span="4"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="16"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="4"><div class="grid-content bg-purple"></div></el-col>
</el-row>
```
:::

### 分栏偏移

支持偏移指定的栏数。

::: demo 通过制定 col 组件的 `offset` 属性可以指定分栏偏移的栏数。
```html
<el-row :gutter="20">
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="6" :offset="6"><div class="grid-content bg-purple"></div></el-col>
</el-row>
<el-row :gutter="20">
  <el-col :span="6" :offset="6"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="6" :offset="6"><div class="grid-content bg-purple"></div></el-col>
</el-row>
<el-row :gutter="20">
  <el-col :span="12" :offset="6"><div class="grid-content bg-purple"></div></el-col>
</el-row>
```
:::

### 对齐方式

对分栏进行灵活的对齐。

::: demo 将 `type` 属性赋值为 'flex'，可以启用 flex 布局，并可通过 `justify` 属性来指定 start, center, end, space-between, space-around 其中的值来定义子元素的排版方式。
```html
<el-row type="flex" class="row-bg">
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="6"><div class="grid-content bg-purple-light"></div></el-col>
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
</el-row>
<el-row type="flex" class="row-bg" justify="center">
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="6"><div class="grid-content bg-purple-light"></div></el-col>
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
</el-row>
<el-row type="flex" class="row-bg" justify="end">
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="6"><div class="grid-content bg-purple-light"></div></el-col>
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
</el-row>
<el-row type="flex" class="row-bg" justify="space-between">
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="6"><div class="grid-content bg-purple-light"></div></el-col>
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
</el-row>
<el-row type="flex" class="row-bg" justify="space-around">
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
  <el-col :span="6"><div class="grid-content bg-purple-light"></div></el-col>
  <el-col :span="6"><div class="grid-content bg-purple"></div></el-col>
</el-row>
```
:::

### Row Attributes
| 参数      | 说明          | 类型      | 可选值                           | 默认值  |
|---------- |-------------- |---------- |--------------------------------  |-------- |
| gutter | 栅格间隔 | number | — | 0 |
| type | 布局模式，可选 flex，现代浏览器下有效 | string | — | — |
| justify | flex 布局下的水平排列方式 | string | start/end/center/space-around/space-between | start |
| align | flex 布局下的垂直排列方式 | string | top/middle/bottom | top |

### Col Attributes
| 参数      | 说明          | 类型      | 可选值                           | 默认值  |
|---------- |-------------- |---------- |--------------------------------  |-------- |
| **span** | 栅格占据的列数，**必选参数** | number | — | — |
| offset | 栅格左侧的间隔格数 | number | — | 0 |
| push |  栅格向右移动格数 | number | — | 0 |
| pull |  栅格向左移动格数 | number | — | 0 |