elementui出现展开后子菜单宽度多出1px问题

.el-menu {
    border-right-width: 0;
}

<template>
    <div class="compen-left-men">
        <el-menu
            default-active="2"
            class="el-menu-vertical-demo"
            @open="handleOpen"
            @close="handleClose"
            background-color="#545c64"
            text-color="#fff"
            :router="startRouter"
            active-text-color="#ffd04b"
        >
            <el-submenu index="1">
                <template slot="title">
                    <i class="el-icon-location"></i>
                    <span>审批管理</span>
                </template>
                <el-menu-item-group>
                    <el-menu-item index="/awaitdo">待审批</el-menu-item>
                    <el-menu-item index="/alreadygreen">已审批</el-menu-item>
                    <el-menu-item index="/approvedby">审批人</el-menu-item>
                    <el-menu-item index="/quickset">快捷语设置</el-menu-item>
                </el-menu-item-group>
                <el-submenu index="1-4">
                    <template slot="title">选项4</template>
                    <el-menu-item index="1-4-1">选项1</el-menu-item>
                </el-submenu>
            </el-submenu>
            <el-menu-item index="2">
                <i class="el-icon-menu"></i>
                <span slot="title">导航二</span>
            </el-menu-item>
            <el-menu-item index="3">
                <i class="el-icon-document"></i>
                <span slot="title">导航三</span>
            </el-menu-item>
        </el-menu>
    </div>
</template>
<script>
export default {
    data() {
        return {
            startRouter: true,
        }
    },
    methods: {
        handleOpen(key, keyPath) {
            console.log(key, keyPath);
        },
        handleClose(key, keyPath) {
            console.log(key, keyPath);
        }
    }
}
</script>
<style lang="less" scoped>
.compen-left-men {
    height: 100%;
}
.el-menu-vertical-demo {
    height: 100%;
}
.el-submenu {
    width: 192px;
}
.el-menu-item {
    min-width: 192px;
    width: 192px;
    border: none;
}
.el-menu {
    border-right-width: 0;
}
</style>