function setUtmCookies() {
  // Helper: get query param from URL
  function getQueryParam(param) {
    const urlParams = new URLSearchParams(window.location.search);
    return urlParams.get(param);
  }

  // Helper: get cookie by name
  function getCookie(name) {
    const match = document.cookie.match(new RegExp('(^| )' + name + '=([^;]+)'));
    return match ? decodeURIComponent(match[2]) : null;
  }

  // Helper: set cookie if not already set
  function setCookieIfEmpty(name, value, days = 90) {
    if (!value) return;
    if (getCookie(name)) return; // Don't overwrite existing cookie
    const date = new Date();
    date.setTime(date.getTime() + days * 24 * 60 * 60 * 1000);
    document.cookie = `${name}=${encodeURIComponent(value)}; expires=${date.toUTCString()}; path=/; SameSite=Lax`;
  }

  // Get UTM params
  const utmSource = getQueryParam('utm_source');
  const utmMedium = getQueryParam('utm_medium');
  const utmCampaign = getQueryParam('utm_campaign');

  // Set cookies only if not already present
  setCookieIfEmpty('utm_source', utmSource, 90);
  setCookieIfEmpty('utm_medium', utmMedium, 90);
  setCookieIfEmpty('utm_campaign', utmCampaign, 90);
}

// Run on page load
setUtmCookies();