Can't find properties defined on other qml file

[hilpara]

I'm trying to use style in main qml. From the Qt side, they propose to use singleton with QtObject

Style.qml
pragma Singleton
import QtQuick 2.0

QtObject {
    property color headerColor: "yellow"
}

Main.qml
import QtQuick
import QtQuick.Controls
import "styles"

ApplicationWindow {
    id: window
    width: 1280
    height: 800
    visible: true

    header: Rectangle {
        id: header
        height: 40
        color: Style.headerColor
    }
}

If I run the program normal, it works. But if I run with QHot, I will get ReferenceError: Style is not defined or Unable to assign [undefined] to QColor. I did try without singleton, but it doesn't help. I did add the path to Style.qml also to qhot-profile.json import-path.