ant-design-vue/components/menu/demo/theme.md

#### 主题 内建了两套主题 `light|dark`，默认 `light`。 #### Menu Themes There are two built-in themes: 'light' and 'dark'. The default value is 'light'.

<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>