const element = document.querySelector('div.giscus')
const observer = new MutationObserver((mutationsList, observer) => {
    for (const record of mutationsList) {
        if (record.type !== 'childList') continue
        const iframe = record.addedNodes[0];
        iframe.addEventListener('load', () => {
            changeTheme()
            // and event bingdings here
        })
        observer.disconnect()
    }
})
observer.observe(element, { childList: true, subtree: true, attributes: true })