无法更改vuetify按钮轮廓颜色

import Vue from 'vue'
import Vuetify from 'vuetify'
import 'vuetify/dist/vuetify.min.css'

Vue.use(Vuetify)

import Vue from 'vue'
import Vuetify from 'vuetify'
import 'vuetify/dist/vuetify.min.css'

Vue.use(Vuetify)

export default new Vuetify({
  theme: {
    themes: {
      light: {
        primary: '#1976D2', // 主要颜色
        secondary: '#424242', // 次要颜色
        accent: '#82B1FF', // 强调颜色
        error: '#FF5252', // 错误颜色
      },
      dark: {
        primary: '#2196F3',
        secondary: '#616161',
        accent: '#FF4081',
        error: '#FF5252',
      },
    },
  },
})

<template>
  <v-btn color="primary">按钮</v-btn>
</template>