diff --git a/public/_4v_attr.js b/public/_4v_attr.js
new file mode 100644
index 0000000..910155c
--- /dev/null
+++ b/public/_4v_attr.js
@@ -0,0 +1,182 @@
+/**
+ * 4Ventures — Universal Attribution Script v1.0
+ * Almacena parámetros UTM y Click IDs en cookie '_4v_attr' (90 días)
+ * e inyecta automáticamente en formularios y enlaces de WhatsApp.
+ */
+(function() {
+  'use strict';
+
+  var COOKIE_NAME = '_4v_attr';
+  var COOKIE_DAYS = 90;
+
+  function getQueryParam(name) {
+    var results = new RegExp('[\?&]' + name + '=([^&#]*)').exec(window.location.href);
+    return results !== null ? decodeURIComponent(results[1].replace(/\+/g, ' ')) : null;
+  }
+
+  function setCookie(name, value, days) {
+    var expires = '';
+    if (days) {
+      var date = new Date();
+      date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
+      expires = '; expires=' + date.toUTCString();
+    }
+    var secure = location.protocol === 'https:' ? '; Secure' : '';
+    document.cookie = name + '=' + encodeURIComponent(JSON.stringify(value)) + expires + '; path=/; SameSite=Lax' + secure;
+  }
+
+  function getCookie(name) {
+    var nameEQ = name + '=';
+    var ca = document.cookie.split(';');
+    for (var i = 0; i < ca.length; i++) {
+      var c = ca[i];
+      while (c.charAt(0) === ' ') c = c.substring(1, c.length);
+      if (c.indexOf(nameEQ) === 0) {
+        try {
+          return JSON.parse(decodeURIComponent(c.substring(nameEQ.length, c.length)));
+        } catch (e) {
+          return null;
+        }
+      }
+    }
+    return null;
+  }
+
+  function detectReferrerSource() {
+    var ref = document.referrer.toLowerCase();
+    if (!ref) return { source: 'direct', medium: 'none' };
+    if (ref.indexOf('google.') !== -1) return { source: 'google', medium: 'organic' };
+    if (ref.indexOf('bing.') !== -1) return { source: 'bing', medium: 'organic' };
+    if (ref.indexOf('instagram.') !== -1) return { source: 'instagram', medium: 'social' };
+    if (ref.indexOf('facebook.') !== -1) return { source: 'facebook', medium: 'social' };
+    if (ref.indexOf('linkedin.') !== -1) return { source: 'linkedin', medium: 'social' };
+    if (ref.indexOf('tiktok.') !== -1) return { source: 'tiktok', medium: 'social' };
+    if (ref.indexOf('youtube.') !== -1) return { source: 'youtube', medium: 'social' };
+    try {
+      var url = new URL(ref);
+      return { source: url.hostname, medium: 'referral' };
+    } catch(e) {
+      return { source: 'referral', medium: 'referral' };
+    }
+  }
+
+  function captureAttribution() {
+    var utmSource = getQueryParam('utm_source');
+    var utmMedium = getQueryParam('utm_medium');
+    var utmCampaign = getQueryParam('utm_campaign');
+    var utmContent = getQueryParam('utm_content');
+    var utmTerm = getQueryParam('utm_term');
+    var gclid = getQueryParam('gclid');
+    var fbclid = getQueryParam('fbclid');
+    var ttclid = getQueryParam('ttclid');
+    var liFatId = getQueryParam('li_fat_id');
+
+    var clickId = gclid || fbclid || ttclid || liFatId || null;
+    var clickType = gclid ? 'gclid' : fbclid ? 'fbclid' : ttclid ? 'ttclid' : liFatId ? 'li_fat_id' : null;
+
+    var existingAttr = getCookie(COOKIE_NAME);
+
+    // Si hay nuevos parámetros en URL, actualizamos o creamos
+    if (utmSource || clickId) {
+      var newAttr = {
+        source: utmSource || (gclid ? 'google' : fbclid ? 'meta' : ttclid ? 'tiktok' : liFatId ? 'linkedin' : 'unknown'),
+        medium: utmMedium || (clickId ? 'cpc' : 'unknown'),
+        campaign: utmCampaign || '',
+        content: utmContent || '',
+        term: utmTerm || '',
+        click_id: clickId,
+        click_type: clickType,
+        landing_page: window.location.href,
+        referrer: document.referrer || '',
+        timestamp: new Date().toISOString()
+      };
+      setCookie(COOKIE_NAME, newAttr, COOKIE_DAYS);
+      return newAttr;
+    }
+
+    // Si no hay params y ya hay cookie previa, la mantenemos
+    if (existingAttr) {
+      return existingAttr;
+    }
+
+    // Si es primera visita sin parámetros, deducimos del referrer
+    var refData = detectReferrerSource();
+    var defaultAttr = {
+      source: refData.source,
+      medium: refData.medium,
+      campaign: '',
+      content: '',
+      term: '',
+      click_id: null,
+      click_type: null,
+      landing_page: window.location.href,
+      referrer: document.referrer || '',
+      timestamp: new Date().toISOString()
+    };
+    setCookie(COOKIE_NAME, defaultAttr, COOKIE_DAYS);
+    return defaultAttr;
+  }
+
+  function injectHiddenFields(attr) {
+    var forms = document.querySelectorAll('form');
+    var fieldKeys = ['source', 'medium', 'campaign', 'content', 'term', 'click_id', 'click_type', 'landing_page', 'referrer'];
+
+    forms.forEach(function(form) {
+      fieldKeys.forEach(function(key) {
+        var inputName = 'utm_' + key;
+        if (key === 'click_id' || key === 'click_type' || key === 'landing_page' || key === 'referrer') {
+          inputName = key;
+        }
+        var val = attr[key] || '';
+        var existing = form.querySelector('input[name="' + inputName + '"]');
+        if (existing) {
+          existing.value = val;
+        } else {
+          var input = document.createElement('input');
+          input.type = 'hidden';
+          input.name = inputName;
+          input.value = val;
+          form.appendChild(input);
+        }
+      });
+    });
+  }
+
+  function injectWhatsAppLinks(attr) {
+    if (!attr.click_id && !attr.source) return;
+    var links = document.querySelectorAll('a[href*="wa.me"], a[href*="api.whatsapp.com"]');
+    var tag = ' [ref:' + (attr.source || 'web') + (attr.click_id ? '-' + attr.click_id.substring(0, 8) : '') + ']';
+    links.forEach(function(link) {
+      var href = link.getAttribute('href');
+      if (href && href.indexOf('[ref:') === -1) {
+        if (href.indexOf('text=') !== -1) {
+          link.setAttribute('href', href + encodeURIComponent(tag));
+        } else {
+          var sep = href.indexOf('?') !== -1 ? '&' : '?';
+          link.setAttribute('href', href + sep + 'text=' + encodeURIComponent('Hola,' + tag));
+        }
+      }
+    });
+  }
+
+  // Inicialización inmediata y en DOMContentLoaded
+  var currentAttr = captureAttribution();
+
+  function init() {
+    injectHiddenFields(currentAttr);
+    injectWhatsAppLinks(currentAttr);
+  }
+
+  if (document.readyState === 'loading') {
+    document.addEventListener('DOMContentLoaded', init);
+  } else {
+    init();
+  }
+
+  // Exponer API global
+  window._4v = {
+    getAttribution: function() { return currentAttr; },
+    refresh: captureAttribution,
+    inject: init
+  };
+})();