节点背景是白色的如何调整颜色echarts tree配置项内容和展示

树状图的原点背景是白色的，如何修改为其他颜色？

      option = {
    title: {
        text: '节点是背景是白的如何调整颜色？只有color属性'
    },
    tooltip: {
        formatter: function(params, ticket, callback) {
            console.log(params);
            //${params.data.city}<br/>${params.data.mobile}<br/>
            return `${params.data.name}`;
        }
    },
    legend: {
        data: ['全部关系','短期关系'],
        selectedMode:'single',
        tooltip: {
        show: true
    }
    },
    
    series: [{
        name: '全部关系',
        type: 'tree',
        label: {
            position: ['-150%', '-80%']
        },
        symbolSize: 20,
        itemStyle: {
            color: '#00ffff'
        },

        data: [{
            openId: "oSjgK0SloULNrcW0SKRpk86VSiVo",
            unionid: "oKcyMw7PmWMYJ4qv_32kUPhnOc-Y",
            name: "禄存",
            country: "China",
            province: "Zhejiang",
            city: "Hangzhou",
            area: null,
            mobile: "13732220681",
            children: [{
                    openId: "oSjgK0cBquVFCAvh0wohCtta0AGA",
                    unionid: "oKcyMw_OqmXzD4nd_tZl_NgXL9sQ",
                    name: "谭洪",
                    country: "China",
                    province: "Zhejiang",
                    city: "Hangzhou",
                    area: null,
                    mobile: "13819103186",
                    children: []
                },
                {
                    openId: "oSjgK0SaSUxtjKYQfmmgoVCRoAto",
                    unionid: "oKcyMw54nfEHJ2HlrnV4NaoOjm9g",
                    name: "Shin1913",
                    country: "China",
                    province: "Zhejiang",
                    city: "Huzhou",
                    area: null,
                    mobile: null,
                    children: []
                },
                {
                    openId: "oSjgK0WrXSk0A7mX9psZ1DyFoDFc",
                    unionid: "664f703c13a1437a9eebb55b85d7034a",
                    name: "张钧士",
                    country: "",
                    province: "",
                    city: "",
                    area: null,
                    mobile: null,
                    children: []
                },
                {
                    openId: "oSjgK0V6KawTPjiJnA1o2Wgx3CI8",
                    unionid: "028d7ee0d6a745dbb319fa3064bd9b0c",
                    name: "林乃文",
                    country: "",
                    province: "",
                    city: "",
                    area: null,
                    mobile: null,
                    children: []
                },
                {
                    openId: "oSjgK0bkqZ4VIIDrj4VG060eyQgk",
                    unionid: "oKcyMw_NmED67YvA4rLrqU2eG4Jk",
                    name: "TO特攻队木易老师",
                    country: "",
                    province: "",
                    city: "",
                    area: null,
                    mobile: null,
                    children: []
                },
                {
                    openId: "oSjgK0XbZjnJhEmxCukrgcAEY9Y8",
                    unionid: "oKcyMw8WHJCoHvJA0f-CpAcnkZLQ",
                    name: "可可",
                    country: "China",
                    province: "Zhejiang",
                    city: "Hangzhou",
                    area: null,
                    mobile: null,
                    children: []
                },
                {
                    openId: "oSjgK0Yzf0dgQTY3pDcp2bwuV2sg",
                    unionid: "oKcyMw0A09mMWBSm7_9tti9v_uUU",
                    name: "轻近秀平",
                    country: "",
                    province: "",
                    city: "",
                    area: null,
                    mobile: null,
                    children: []
                }
            ]
        }]
    },{
        name: '短期关系',
        type: 'tree',
        label: {
            position: ['-150%', '-80%']
        },
        symbolSize: 20,
        itemStyle: {
            color: '#00ffff'
        },

        data: [{
            openId: "oSjgK0SloULNrcW0SKRpk86VSiVo",
            unionid: "oKcyMw7PmWMYJ4qv_32kUPhnOc-Y",
            name: "禄存2",
            country: "China",
            province: "Zhejiang",
            city: "Hangzhou",
            area: null,
            mobile: "13732220681",
            children: [{
                    openId: "oSjgK0cBquVFCAvh0wohCtta0AGA",
                    unionid: "oKcyMw_OqmXzD4nd_tZl_NgXL9sQ",
                    name: "谭洪",
                    country: "China",
                    province: "Zhejiang",
                    city: "Hangzhou",
                    area: null,
                    mobile: "13819103186",
                    children: []
                },
                {
                    openId: "oSjgK0SaSUxtjKYQfmmgoVCRoAto",
                    unionid: "oKcyMw54nfEHJ2HlrnV4NaoOjm9g",
                    name: "Shin1913",
                    country: "China",
                    province: "Zhejiang",
                    city: "Huzhou",
                    area: null,
                    mobile: null,
                    children: []
                },
                {
                    openId: "oSjgK0WrXSk0A7mX9psZ1DyFoDFc",
                    unionid: "664f703c13a1437a9eebb55b85d7034a",
                    name: "张钧士",
                    country: "",
                    province: "",
                    city: "",
                    area: null,
                    mobile: null,
                    children: []
                },
                {
                    openId: "oSjgK0V6KawTPjiJnA1o2Wgx3CI8",
                    unionid: "028d7ee0d6a745dbb319fa3064bd9b0c",
                    name: "林乃文",
                    country: "",
                    province: "",
                    city: "",
                    area: null,
                    mobile: null,
                    children: []
                },
                {
                    openId: "oSjgK0bkqZ4VIIDrj4VG060eyQgk",
                    unionid: "oKcyMw_NmED67YvA4rLrqU2eG4Jk",
                    name: "TO特攻队木易老师",
                    country: "",
                    province: "",
                    city: "",
                    area: null,
                    mobile: null,
                    children: []
                },
                {
                    openId: "oSjgK0XbZjnJhEmxCukrgcAEY9Y8",
                    unionid: "oKcyMw8WHJCoHvJA0f-CpAcnkZLQ",
                    name: "可可",
                    country: "China",
                    province: "Zhejiang",
                    city: "Hangzhou",
                    area: null,
                    mobile: null,
                    children: []
                },
                {
                    openId: "oSjgK0Yzf0dgQTY3pDcp2bwuV2sg",
                    unionid: "oKcyMw0A09mMWBSm7_9tti9v_uUU",
                    name: "轻近秀平",
                    country: "",
                    province: "",
                    city: "",
                    area: null,
                    mobile: null,
                    children: []
                }
            ]
        }]
    }]
};