function waitForElement(selector, callback) {
const element = document.querySelector(selector);
if (element) {
callback(element);
} else {
setTimeout(() => {
waitForElement(selector, callback);
}, 500);
}
}

function modifyHeaderElement(headerElement) {
const pricingModel = document.querySelector("#app > div > main > div > div > div > div.v-card__text > div.container.px-0.container--fluid > div > div:nth-child(2) > div.my-4.v-card.v-sheet.v-sheet--outlined.theme--dark > div.v-card__text > div > div > div:nth-child(1) > div > div.v-card__text.headline.text-center.px-0");
const pricing_model = pricingModel.textContent.trim();
const exclamationMark = document.createElement('span');

if (pricing_model === 'CPC GOAL' || pricing_model === 'CPM GOAL') {
const priceElements = document.querySelectorAll("#app > div > main > div > div > div > div.v-card__text > div.container.px-0.container--fluid > div > div:nth-child(2) > div.my-4.v-card.v-sheet.v-sheet--outlined.theme--dark > div.v-card__text > div > div > div > div > div.v-card__text.headline.text-center.px-0");
const lastPriceElement = priceElements[priceElements.length - 1];
const price = lastPriceElement.textContent;
exclamationMark.textContent = ' [' + pricing_model + ' = ' + lastPriceElement + price + ']';
exclamationMark.style.color = 'Violet';
} else {
const priceElement = document.querySelector("#app > div > main > div > div > div > div.v-card__text > div.container.px-0.container--fluid > div > div:nth-child(2) > div.my-4.v-card.v-sheet.v-sheet--outlined.theme--dark > div.v-card__text > div > div > div:nth-child(3) > div > div.v-card__text.headline.text-center.px-0");
const price = parseFloat(priceElement.textContent);
const priceboxPriceElement = document.querySelector("#app > div > main > div > div > div > div.v-card__text > div.container.px-0.container--fluid > div > div:nth-child(2) > div.my-4.v-card.v-sheet.v-sheet--outlined.theme--dark > div.v-card__text > div > div > div:nth-child(4) > div > div.v-card__text.headline.text-center.px-0");
const priceboxPrice = parseFloat(priceboxPriceElement.textContent);
const divisionResult = price / priceboxPrice;
exclamationMark.textContent = ' [delta = ' + divisionResult.toFixed(1) + ']';

if (divisionResult < 3) {
  exclamationMark.style.color = 'Lime';
} else {
  exclamationMark.style.color = 'FireBrick';
}
}

headerElement.textContent = 'Price info ';
headerElement.appendChild(exclamationMark);
const observer = new MutationObserver((mutations) => {
console.log('Header element mutated:', mutations);
});
observer.observe There should be exactly 4 paragraphs separated by the markdown divider: ***.
user