diff --git a/src/content/content.js b/src/content/content.js
index 35b4915..0641d10 100644
--- a/src/content/content.js
+++ b/src/content/content.js
@@ -10,6 +10,13 @@
 (function () {
   'use strict';
 
+  // --- Safe innerHTML replacement (AMO-compliant, page world) ---
+  function safeHTML(el, html) {
+    const template = document.createElement('template');
+    template.innerHTML = html;
+    el.replaceChildren(...template.content.childNodes);
+  }
+
   // ============================================================
   // Load config from the injector script's data attribute
   // ============================================================
@@ -514,7 +521,7 @@
 
     const more = warnings.length > 5 ? `<div class="ss-ad-more">+${warnings.length - 5} more</div>` : '';
 
-    warningEl.innerHTML = `
+    safeHTML(warningEl, `
       <div class="ss-ad-header">
         <strong>Silent Send detected potential PPI that may not be substituted:</strong>
         <button class="ss-ad-close">&times;</button>
@@ -522,7 +529,7 @@
       ${items}
       ${more}
       <div class="ss-ad-footer">${settings.autoRedactDetected !== false ? 'Auto-redacted before sending.' : 'These were sent as-is.'} Consider adding them to your identity or mappings.</div>
-    `;
+    `);
 
     warningEl.classList.add('visible');
 
@@ -1165,7 +1172,7 @@
         </div>`
       ).join('');
 
-      docPreviewEl.innerHTML = `
+      safeHTML(docPreviewEl, `
         <div class="ss-dp-header">
           <strong>PPI found in ${esc(filename)}</strong>
           <span class="ss-dp-count">${preview.replacementCount} item(s)</span>
@@ -1176,7 +1183,7 @@
           <button class="ss-dp-btn ss-dp-confirm">Substitute & Upload</button>
           <button class="ss-dp-btn ss-dp-cancel">Upload Original</button>
         </div>
-      `;
+      `);
       docPreviewEl.classList.add('visible');
       const confirm = docPreviewEl.querySelector('.ss-dp-confirm');
       const cancel = docPreviewEl.querySelector('.ss-dp-cancel');
@@ -1657,7 +1664,7 @@
 
     const more = warnings.length > 8 ? `<div class="ss-ad-more">+${warnings.length - 8} more</div>` : '';
 
-    preSendWarningEl.innerHTML = `
+    safeHTML(preSendWarningEl, `
       <div class="ss-ad-header">
         <strong>Potential PPI detected — not yet configured:</strong>
         <button class="ss-ad-close">&times;</button>
@@ -1668,7 +1675,7 @@
         ${settings.autoRedactDetected !== false ? 'Auto-redacted with standard placeholders.' : 'These were sent as-is.'}
         ${settings.autoAddDetected !== false ? ' Click + to add a permanent mapping.' : ''}
       </div>
-    `;
+    `);
 
     preSendWarningEl.classList.add('visible');
 
diff --git a/src/options/options.js b/src/options/options.js
index 3e5d010..5f6eaa6 100644
--- a/src/options/options.js
+++ b/src/options/options.js
@@ -14,6 +14,12 @@ let passwordsRevealed = false;
 
 const $ = (sel) => document.querySelector(sel);
 
+// --- Safe innerHTML replacement (AMO-compliant) ---
+function safeHTML(el, html) {
+  const doc = new DOMParser().parseFromString(html, 'text/html');
+  el.replaceChildren(...doc.body.childNodes);
+}
+
 document.addEventListener('DOMContentLoaded', async () => {
   mappings = await Storage.getMappings();
   settings = await Storage.getSettings();
@@ -405,11 +411,11 @@ function renderMappings() {
   const nonPasswordMappings = mappings.filter(m => m.category !== 'password');
 
   if (nonPasswordMappings.length === 0) {
-    tbody.innerHTML = '<tr><td colspan="6" style="text-align:center;color:#9ca3af;padding:24px">No mappings configured</td></tr>';
+    safeHTML(tbody, '<tr><td colspan="6" style="text-align:center;color:#9ca3af;padding:24px">No mappings configured</td></tr>');
     return;
   }
 
-  tbody.innerHTML = nonPasswordMappings
+  safeHTML(tbody, nonPasswordMappings
     .map(
       (m) => `
     <tr data-id="${m.id}">
@@ -427,7 +433,7 @@ function renderMappings() {
     </tr>
   `
     )
-    .join('');
+    .join(''));
 
   // Bind
   tbody.querySelectorAll('.btn-delete').forEach((btn) => {
@@ -457,14 +463,14 @@ function renderPasswords() {
   const noMsg = $('#noPasswordsMsg');
 
   if (passwordMappings.length === 0) {
-    tbody.innerHTML = '';
+    tbody.replaceChildren();
     noMsg.style.display = 'block';
     return;
   }
 
   noMsg.style.display = 'none';
 
-  tbody.innerHTML = passwordMappings.map(m => {
+  safeHTML(tbody, passwordMappings.map(m => {
     const displayReal = passwordsRevealed
       ? escapeHtml(m.real)
       : '&bull;&bull;&bull;&bull;&bull;&bull;&bull;&bull;';
@@ -481,7 +487,7 @@ function renderPasswords() {
       </td>
       <td><button class="btn btn-sm btn-danger btn-delete-pw">&times;</button></td>
     </tr>`;
-  }).join('');
+  }).join(''));
 
   // Bind delete
   tbody.querySelectorAll('.btn-delete-pw').forEach(btn => {
@@ -518,11 +524,11 @@ async function renderLog() {
 
   const list = $('#logList');
   if (log.length === 0) {
-    list.innerHTML = '<div style="text-align:center;color:#9ca3af;padding:24px">No activity logged</div>';
+    safeHTML(list, '<div style="text-align:center;color:#9ca3af;padding:24px">No activity logged</div>');
     return;
   }
 
-  list.innerHTML = log
+  safeHTML(list, log
     .slice(0, 100)
     .map((entry) => {
       const time = new Date(entry.timestamp).toLocaleString();
@@ -535,7 +541,7 @@ async function renderLog() {
       </div>
     `;
     })
-    .join('');
+    .join(''));
 }
 
 // --- Custom Domains ---
@@ -582,18 +588,18 @@ function renderDomains() {
   const domains = settings.customDomains || [];
 
   if (domains.length === 0) {
-    list.innerHTML = '<div style="text-align:center;color:#9ca3af;padding:12px;font-size:13px">No custom domains. Built-in sites (Claude, ChatGPT, Grok, Gemini, localhost) are always active.</div>';
+    safeHTML(list, '<div style="text-align:center;color:#9ca3af;padding:12px;font-size:13px">No custom domains. Built-in sites (Claude, ChatGPT, Grok, Gemini, localhost) are always active.</div>');
     return;
   }
 
-  list.innerHTML = domains
+  safeHTML(list, domains
     .map((d, i) => `
       <div class="domain-item" style="display:flex;align-items:center;justify-content:space-between;padding:8px;background:#f9fafb;border-radius:6px;margin-bottom:4px">
         <span style="font-size:13px;font-family:monospace">${escapeHtml(d)}</span>
         <button class="btn btn-sm btn-danger btn-remove-domain" data-index="${i}">&times;</button>
       </div>
     `)
-    .join('');
+    .join(''));
 
   list.querySelectorAll('.btn-remove-domain').forEach((btn) => {
     btn.addEventListener('click', async () => {
@@ -1239,11 +1245,11 @@ async function renderVersionHistory() {
   const snapshots = await VersionHistory.getSnapshots();
 
   if (snapshots.length === 0) {
-    list.innerHTML = '<div style="text-align:center;color:#9ca3af;padding:12px">No snapshots yet. Snapshots are created on each sync.</div>';
+    safeHTML(list, '<div style="text-align:center;color:#9ca3af;padding:12px">No snapshots yet. Snapshots are created on each sync.</div>');
     return;
   }
 
-  list.innerHTML = snapshots.map(s => {
+  safeHTML(list, snapshots.map(s => {
     const time = new Date(s.timestamp).toLocaleString();
     const mappingCount = (s.data?.mappings || []).length;
     return `<div style="display:flex;align-items:center;justify-content:space-between;padding:8px;background:#f9fafb;border-radius:6px;margin-bottom:4px">
@@ -1254,7 +1260,7 @@ async function renderVersionHistory() {
       </div>
       <button class="btn btn-sm btn-restore-snapshot" data-id="${s.id}">Restore</button>
     </div>`;
-  }).join('');
+  }).join(''));
 
   list.querySelectorAll('.btn-restore-snapshot').forEach(btn => {
     btn.addEventListener('click', async () => {
@@ -1299,13 +1305,13 @@ async function renderDevices() {
   const entries = Object.values(devices);
 
   if (entries.length === 0) {
-    list.innerHTML = '<div style="text-align:center;color:#9ca3af;padding:12px">No devices synced yet. Push or pull to register this device.</div>';
+    safeHTML(list, '<div style="text-align:center;color:#9ca3af;padding:12px">No devices synced yet. Push or pull to register this device.</div>');
     return;
   }
 
   entries.sort((a, b) => (b.lastSync || 0) - (a.lastSync || 0));
 
-  list.innerHTML = `<table style="width:100%;font-size:12px;border-collapse:collapse">
+  safeHTML(list, `<table style="width:100%;font-size:12px;border-collapse:collapse">
     <thead><tr style="text-align:left;border-bottom:1px solid #e5e7eb">
       <th style="padding:6px">Device</th>
       <th style="padding:6px">Browser</th>
@@ -1322,7 +1328,7 @@ async function renderDevices() {
         <td style="padding:6px">${!isCurrent ? `<button class="btn btn-sm btn-danger btn-remove-device" data-id="${d.id}">&times;</button>` : ''}</td>
       </tr>`;
     }).join('')}</tbody>
-  </table>`;
+  </table>`);
 
   list.querySelectorAll('.btn-remove-device').forEach(btn => {
     btn.addEventListener('click', async () => {
@@ -1399,9 +1405,9 @@ async function showOrgJoined() {
   const compliance = await OrgPolicy.checkCompliance();
   const statusEl = $('#orgComplianceStatus');
   if (compliance.compliant) {
-    statusEl.innerHTML = '<span style="color:#10b981">&#10003; Compliant — all required fields configured</span>';
+    safeHTML(statusEl, '<span style="color:#10b981">&#10003; Compliant — all required fields configured</span>');
   } else {
-    statusEl.innerHTML = `<span style="color:#b45309">Missing: ${compliance.missing.join(', ')}</span>`;
+    safeHTML(statusEl, `<span style="color:#b45309">Missing: ${compliance.missing.join(', ')}</span>`);
   }
 
   const reqMappings = policy?.requiredMappings || [];
@@ -1553,7 +1559,7 @@ async function checkConflicts() {
 
 function renderConflicts(conflicts) {
   const list = $('#conflictList');
-  list.innerHTML = conflicts.map(c => `
+  safeHTML(list, conflicts.map(c => `
     <div style="padding:10px;background:#fffbeb;border:1px solid #fde68a;border-radius:6px;margin-bottom:8px" data-conflict-id="${c.id}">
       <div style="font-size:12px;font-weight:500;margin-bottom:6px">${escapeHtml(c.path)}</div>
       <div style="display:flex;gap:12px;flex-wrap:wrap;margin-bottom:8px">
@@ -1571,7 +1577,7 @@ function renderConflicts(conflicts) {
         <button class="btn btn-sm btn-resolve" data-id="${c.id}" data-choice="remote">Keep Remote</button>
       </div>
     </div>
-  `).join('');
+  `).join(''));
 
   list.querySelectorAll('.btn-resolve').forEach(btn => {
     btn.addEventListener('click', async () => {
@@ -1632,10 +1638,10 @@ async function handleBulkImport(e) {
       result.identity.usernames.filter(u => !u.substitute).length +
       result.identity.phones.filter(p => !p.substitute).length;
 
-    $('#bulkImportSummary').innerHTML = `
+    safeHTML($('#bulkImportSummary'), `
       Found: ${parts.join(', ')}.
       ${needsMapping > 0 ? `<span style="color:#b45309">${needsMapping} item(s) need substitutes — you can add them after import.</span>` : ''}
-    `;
+    `);
 
     // Build preview list
     const items = [];
@@ -1655,8 +1661,8 @@ async function handleBulkImport(e) {
       items.push(`<div><span style="color:#6b7280">${escapeHtml(m.category)}:</span> <strong>${escapeHtml(m.real)}</strong>${m.substitute ? ' → ' + escapeHtml(m.substitute) : ' <span style="color:#b45309">needs substitute</span>'}</div>`);
     }
 
-    $('#bulkImportItems').innerHTML = items.slice(0, 50).join('') +
-      (items.length > 50 ? `<div style="color:#6b7280;margin-top:4px">+${items.length - 50} more...</div>` : '');
+    safeHTML($('#bulkImportItems'), items.slice(0, 50).join('') +
+      (items.length > 50 ? `<div style="color:#6b7280;margin-top:4px">+${items.length - 50} more...</div>` : ''));
 
     $('#bulkImportPreview').style.display = 'block';
 
diff --git a/src/popup/popup.js b/src/popup/popup.js
index 4fdcf25..76de432 100644
--- a/src/popup/popup.js
+++ b/src/popup/popup.js
@@ -18,6 +18,12 @@ let settings = {};
 const $ = (sel) => document.querySelector(sel);
 const $$ = (sel) => document.querySelectorAll(sel);
 
+// --- Safe innerHTML replacement (AMO-compliant) ---
+function safeHTML(el, html) {
+  const doc = new DOMParser().parseFromString(html, 'text/html');
+  el.replaceChildren(...doc.body.childNodes);
+}
+
 // --- Init ---
 document.addEventListener('DOMContentLoaded', async () => {
   // Check if locked BEFORE trying to read sensitive data
@@ -302,11 +308,11 @@ async function showLockedUI() {
 // --- Profiles ---
 function renderProfileSelector() {
   const select = $('#profileSelect');
-  select.innerHTML = profiles.map(p =>
+  safeHTML(select, profiles.map(p =>
     `<option value="${p.id}" ${p.id === currentProfileId ? 'selected' : ''}>` +
     `${escapeHtml(p.name)}${p.active ? '' : ' (off)'}` +
     `</option>`
-  ).join('');
+  ).join(''));
 
   const profile = profiles.find(p => p.id === currentProfileId);
   $('#profileActive').checked = profile?.active ?? true;
@@ -355,7 +361,7 @@ function renderFieldList(fieldName, items) {
     items = [{ real: '', substitute: '', type: config.defaultType || '' }];
   }
 
-  container.innerHTML = items.map((item, i) => {
+  safeHTML(container, items.map((item, i) => {
     let typeHtml = '';
     if (config.typeOptions) {
       typeHtml = `<select class="id-type-select" data-index="${i}" style="padding:3px 2px;font-size:10px;border:1px solid #e5e7eb;border-radius:3px;width:42px">` +
@@ -371,7 +377,7 @@ function renderFieldList(fieldName, items) {
       <input type="text" class="input input-sm id-sub" value="${escapeAttr(item.substitute || '')}" placeholder="${config.placeholderSub}">
       <button class="btn-remove" title="Remove">&times;</button>
     </div>`;
-  }).join('');
+  }).join(''));
 
   // Bind remove buttons
   container.querySelectorAll('.btn-remove').forEach(btn => {
@@ -420,13 +426,13 @@ function loadIdentityForm() {
           ).join('') +
           `</select>`;
       }
-      tempDiv.innerHTML = `<div class="id-entry-row" data-index="${count}">
+      safeHTML(tempDiv, `<div class="id-entry-row" data-index="${count}">
         ${typeHtml}
         <input type="text" class="input input-sm id-real" placeholder="${config.placeholderReal}">
         <span class="arrow" style="font-size:12px">&rarr;</span>
         <input type="text" class="input input-sm id-sub" placeholder="${config.placeholderSub}">
         <button class="btn-remove" title="Remove">&times;</button>
-      </div>`;
+      </div>`);
       const row = tempDiv.firstElementChild;
       container.appendChild(row);
       row.querySelector('.btn-remove').addEventListener('click', () => {
@@ -576,11 +582,11 @@ function renderMappings() {
   const list = $('#mappingList');
 
   if (mappings.length === 0) {
-    list.innerHTML = '<div class="empty-state">No mappings yet. Add your first one above.</div>';
+    safeHTML(list, '<div class="empty-state">No mappings yet. Add your first one above.</div>');
     return;
   }
 
-  list.innerHTML = mappings
+  safeHTML(list, mappings
     .map(
       (m) => `
     <div class="mapping-item" data-id="${m.id}">
@@ -597,7 +603,7 @@ function renderMappings() {
     </div>
   `
     )
-    .join('');
+    .join(''));
 
   // Bind actions
   list.querySelectorAll('.btn-delete').forEach((btn) => {
@@ -631,11 +637,11 @@ async function renderActivity() {
   countEl.textContent = `${log.length} substitution${log.length !== 1 ? 's' : ''} logged`;
 
   if (log.length === 0) {
-    list.innerHTML = '<div class="empty-state">No activity yet.</div>';
+    safeHTML(list, '<div class="empty-state">No activity yet.</div>');
     return;
   }
 
-  list.innerHTML = log
+  safeHTML(list, log
     .slice(0, 50)
     .map((entry) => {
       const time = new Date(entry.timestamp).toLocaleTimeString([], {
@@ -653,7 +659,7 @@ async function renderActivity() {
       </div>
     `;
     })
-    .join('');
+    .join(''));
 }
 
 // --- Test Diff (Strip: real → fake) ---
@@ -663,7 +669,7 @@ function renderTestDiff() {
   const stats = $('#diffStats');
 
   if (!input) {
-    output.innerHTML = '';
+    output.replaceChildren();
     stats.textContent = '';
     return;
   }
@@ -703,7 +709,7 @@ function renderTestDiff() {
       `<span class="sub-highlight" style="background:#fee2e2;color:#dc2626" title="${escapeHtml(r.pattern)}">${escapedReplaced}</span>`
     );
   }
-  output.innerHTML = html;
+  safeHTML(output, html);
 
   const smartCount = smartResult.replacements.length;
   const explicitCount = explicitResult.replacements.length;
@@ -723,10 +729,12 @@ function renderTestDiff() {
 
   // Show PPI warnings below stats
   if (ppiWarnings.length > 0) {
-    stats.innerHTML += `<div style="margin-top:6px;padding:6px 8px;background:#fef3c7;border-radius:4px;color:#92400e;font-size:11px">
+    const ppiDiv = document.createElement('div');
+    safeHTML(ppiDiv, `<div style="margin-top:6px;padding:6px 8px;background:#fef3c7;border-radius:4px;color:#92400e;font-size:11px">
       <strong>Unconfigured PPI detected:</strong>
       ${ppiWarnings.map(w => `<div style="margin-top:3px"><code style="background:#fff;padding:1px 4px;border-radius:2px;color:#b45309">${escapeHtml(w.value)}</code> — ${w.hint}</div>`).join('')}
-    </div>`;
+    </div>`);
+    stats.appendChild(ppiDiv);
   }
 }
 
@@ -737,7 +745,7 @@ function renderRevealDiff() {
   const stats = $('#revealStats');
 
   if (!input) {
-    output.innerHTML = '';
+    output.replaceChildren();
     stats.textContent = '';
     return;
   }
@@ -783,7 +791,7 @@ function renderRevealDiff() {
       `<span class="sub-highlight" title="Was: ${escapeHtml(pair.substitute)}" style="background:#dbeafe;color:#1d4ed8">${escapedReal}</span>`
     );
   }
-  output.innerHTML = html;
+  safeHTML(output, html);
   stats.textContent = `${totalCount} value${totalCount !== 1 ? 's' : ''} revealed`;
 }