BootstrapVue 스타일이 효과가 없어서 곤란해요.

원인: 원하는 반이 없습니다

<b-form-group id="input-group-3" label="Food:" label-for="input-3">
<b-form-select
  id="input-3"
  v-model="form.food"
  :options="foods"
  required
></b-form-select>
</b-form-group>

<select data-v-91bde120="" id="input-3" required="required" aria-required="true" class="custom-select">
	<option data-v-91bde120="" value="">Select One</option><option data-v-91bde120="" value="Carrots">Carrots</option>
	<option data-v-91bde120="" value="Beans">Beans</option>
	<option data-v-91bde120="" value="Tomatoes">Tomatoes</option>
	<option data-v-91bde120="" value="Corn">Corn</option>
</select>

해결책

<b-form-group id="input-group-3" label="Food:" label-for="input-3">
<b-form-select
  id="input-3"
  v-model="form.food"
  :options="foods"
  required
  plain
></b-form-select>
</b-form-group>

<select data-v-91bde120="" id="input-3" required="required" aria-required="true" class="form-control">
	<option data-v-91bde120="" value="">Select One</option><option data-v-91bde120="" value="Carrots">Carrots</option>
	<option data-v-91bde120="" value="Beans">Beans</option>
	<option data-v-91bde120="" value="Tomatoes">Tomatoes</option>
	<option data-v-91bde120="" value="Corn">Corn</option>
</select>

<b-form-group id="input-group-4" v-slot="{ ariaDescribedby }">
<b-form-checkbox-group
  v-model="form.checked"
  id="checkboxes-4"
  :aria-describedby="ariaDescribedby"
  plain
>
  <b-form-checkbox value="me">Check me out</b-form-checkbox>
  <b-form-checkbox value="that">Check that out</b-form-checkbox>
</b-form-checkbox-group>
</b-form-group>