message: feat(ConfigProvider): dark theme class
diff: import {
  + watch,
  provide,
  computed,
  defineComponent,
  @@ -7,7 +8,12 @@ import {
  type CSSProperties,
  type ExtractPropTypes,
  } from 'vue';
  -import { kebabCase, makeStringProp, createNamespace } from '../utils';
  +import {
  + inBrowser,
  + kebabCase,
  + makeStringProp,
  + createNamespace,
  +} from '../utils';
  const [name, bem] = createNamespace('config-provider');
  @@ -49,13 +55,20 @@ export default defineComponent({
  }
  });
  + if (inBrowser) {
  + watch(
  + () => props.theme,
  + (newVal, oldVal) => {
  + document.body.classList.remove(`van-theme-${oldVal}`);
  + document.body.classList.add(`van-theme-${newVal}`);
  + }
  + );
  + }
  +
  provide(CONFIG_PROVIDER_KEY, props);
  return () => (
  - <props.tag
  - class={[bem(), `van-theme-${props.theme}`]}
  - style={style.value}
  - >
  + <props.tag class={bem()} style={style.value}>
  {slots.default?.()}
  </props.tag>
  );
  