实现效果：

点击切换箭头方向

实现代码

    <divclass="modelPart"@click="showClick"><div class="modelPart_left"><img:src=aidefalutIconclass="sNodeIcon"><div>{{ selectModel }}</div><div class="chatText">CHAT</div></div><span :class="dropdown==true?'expand':'down'"class="arrow"></span></div>

<script setup>import { useI18n } from 'vue-i18n';const { t } = useI18n();import { onMounted, ref, watch } from 'vue'const dropdown = ref(false)// 点击事件function showClick () {dropdown.value = !dropdown.value}
</script>

css">  .arrow {display: inline-block;width: 7px;height: 7px;margin-top: -3px;margin-left: 9px;border-top: 2px solid #ffffff;border-left: 2px solid #ffffff;}.down{transform: rotate(225deg);transform-origin: center;transition: all 0.3s;
}.expand {transform: translate(0, 2px) rotate(45deg);transform-origin: center;transition: all 0.3s;}