VUE3使用Element-Plus时如何修改ElMessage中的文字大小

<style >
.el-message__content {
  font-size: 28px;
}
</style>

<template>
</template>
<script setup>
import { ElMessage } from 'element-plus'
let style= document.createElement("style");
style.innerHTML = ".el-message__content{font-size:28px;}";
document.body.appendChild(style);
ElMessage({message: "测试提示",type: "warning",duration:0})
</script>
<style>
</style>

 setup() {
    const state = reactive({
      size: 1, //默认字体大小值
      val: "",//双向绑定的值
      //字体数组
      posts: [
        { id: 1, name: "28", size: 1 },
        { id: 2, name: "32", size: 2 },
        { id: 3, name: "10", size: 2 },
      ],
})

<span :style="{ fontSize: size + 'em' }">字体大小</span>
    <el-select v-model="val" @change="changtext">
      <el-option
        v-for="(item, index) in posts"
        :key="index"
        :label="item.name"
        :value="item.id"
      />
    </el-select>

 //选择字体事件
      changtext(val) {
        //如果选中的是10号字体就字体大小相减
        if (val == 3) {
          state.size = state.size -= 1;
        } else {
          state.size = state.size += 1;
        }
      },