<cn>
#### 主题
内建了两套主题 `light|dark`，默认 `light`。
</cn>

<us>
#### Menu Themes
There are two built-in themes: 'light' and 'dark'. The default value is 'light'.
</us>

```html
<template>
<div>
  <a-switch
    defaultChecked
    @change="changeTheme"
    checkedChildren="dark"
    unCheckedChildren="light"
  />
  <br />
  <br />
  <a-menu
    style="width: 256px"
    :defaultSelectedKeys="['1']"
    :defaultOpenKeys="['sub1']"
    mode="inline"
    :theme="theme"
    :selectedKeys="[current]"
    @click="handleClick"
  >
    <a-menu-item key="1">
      <a-icon type="mail" />
      Navigation One
    </a-menu-item>
    <a-menu-item key="2">
      <a-icon type="calendar" />
      Navigation Two
    </a-menu-item>
    <a-sub-menu key="sub1">
      <span slot="title"><a-icon type="appstore" /><span>Navigation Three</span></span>
      <a-menu-item key="3">Option 3</a-menu-item>
      <a-menu-item key="4">Option 4</a-menu-item>
      <a-sub-menu key="sub1-2" title="Submenu">
        <a-menu-item key="5">Option 5</a-menu-item>
        <a-menu-item key="6">Option 6</a-menu-item>
      </a-sub-menu>
    </a-sub-menu>
    <a-sub-menu key="sub2">
      <span slot="title"><a-icon type="setting" /><span>Navigation Four</span></span>
      <a-menu-item key="7">Option 7</a-menu-item>
      <a-menu-item key="8">Option 8</a-menu-item>
      <a-menu-item key="9">Option 9</a-menu-item>
      <a-menu-item key="10">Option 10</a-menu-item>
    </a-sub-menu>
  </a-menu>
</div>
</template>
<script>
export default {
  data () {
    return {
      current: '1',
      theme: 'dark',
    }
  },
  methods: {
    handleClick (e) {
      console.log('click ', e)
      this.current = e.key
    },
    changeTheme (checked) {
      this.theme = checked ? 'dark' : 'light'
    },
  },
}

</script>
```
