china_addons/oec_theme_backend/data/res_theme_data.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <data noupdate="0">

        <record id="main_company_theme" model="res.theme">
            <field name="company_id" ref="base.main_company"/>
            <field name="type">company</field>
        </record>

        <record id="base.main_company" model="res.company">
            <field name="theme_id" ref="oec_theme_backend.main_company_theme"/>
        </record>

        <record id="user_admin_theme" model="res.theme">
            <field name="user_id" ref="base.user_admin"/>
            <field name="type">user</field>
        </record>

        <record id="base.user_admin" model="res.users">
            <field name="theme_id" ref="oec_theme_backend.user_admin_theme"/>
        </record>


    </data>
</odoo>