how to align overlay for ConfirmPopup under unstyled mode

[ShiYaoDiving]

In the ConfirmPopup.vue:

        alignOverlay() {
            absolutePosition(this.container, this.target, false);

            const containerOffset = getOffset(this.container);
            const targetOffset = getOffset(this.target);
            let arrowLeft = 0;

            if (containerOffset.left < targetOffset.left) {
                arrowLeft = targetOffset.left - containerOffset.left;
            }

            this.container.style.setProperty($dt('confirmpopup.arrow.left').name, `${arrowLeft}px`);

            if (containerOffset.top < targetOffset.top) {
                this.container.setAttribute('data-p-confirmpopup-flipped', 'true');
                !this.isUnstyled && addClass(this.container, 'p-confirmpopup-flipped');
            }
        },

How to get the targetOffset.left and containerOffset.left？
And what can i do to under pt to set " this.container.style.setProperty($dt('confirmpopup.arrow.left').name, ${arrowLeft}px);" ？

[ShiYaoDiving]

I know how to get the targetOffset, by getOffset(state.target), But I cannot get the containerOffset~~~