diff --git a/index.html b/index.html
index 35ecef7..813b355 100644
--- a/index.html
+++ b/index.html
@@ -461,7 +461,7 @@
                             <div id="signature-preview" style="display:none;padding:0.5rem 0.75rem;margin-top:0.25rem;border-left:3px solid #d0d5dd;color:#888;font-size:0.82rem;white-space:pre-line;"></div>
                             <div style="display:flex;justify-content:space-between;align-items:center;gap:0.5rem;margin-top:0.5rem;">
                                 <label style="display:flex;align-items:center;gap:0.4rem;font-size:0.82rem;color:#888;cursor:pointer;white-space:nowrap;">
-                                    <input type="checkbox" id="reply-no-signature" checked> Älä käytä allekirjoitusta
+                                    <input type="checkbox" id="reply-use-signature" checked> Käytä allekirjoitusta
                                 </label>
                                 <button class="btn-primary" id="btn-send-reply">Lähetä vastaus</button>
                             </div>
diff --git a/script.js b/script.js
index 79906a1..e9a858d 100644
--- a/script.js
+++ b/script.js
@@ -1601,9 +1601,9 @@ async function showTicketDetail(id, companyId = '') {
         // Allekirjoituksen esikatselu
         function updateSignaturePreview(mbId) {
             const sigPreview = document.getElementById('signature-preview');
-            const noSigCheck = document.getElementById('reply-no-signature');
+            const useSigCheck = document.getElementById('reply-use-signature');
             const sig = currentUserSignatures[mbId] || '';
-            if (sig && !(noSigCheck && noSigCheck.checked)) {
+            if (sig && useSigCheck && useSigCheck.checked) {
                 sigPreview.textContent = '-- \n' + sig;
                 sigPreview.style.display = 'block';
             } else {
@@ -1613,9 +1613,9 @@ async function showTicketDetail(id, companyId = '') {
         updateSignaturePreview(ticket.mailbox_id || '');
 
         // Allekirjoitus-checkbox: päivitä esikatselu vaihdettaessa
-        const noSigCheckbox = document.getElementById('reply-no-signature');
-        if (noSigCheckbox) {
-            noSigCheckbox.addEventListener('change', () => {
+        const useSigCheckbox = document.getElementById('reply-use-signature');
+        if (useSigCheckbox) {
+            useSigCheckbox.addEventListener('change', () => {
                 const mbSelect = document.getElementById('reply-mailbox-select');
                 updateSignaturePreview(mbSelect ? mbSelect.value : '');
             });
@@ -1673,23 +1673,23 @@ document.querySelectorAll('.btn-reply-tab').forEach(btn => {
         const sigPrev = document.getElementById('signature-preview');
         const metaFields = document.getElementById('reply-meta-fields');
         const tplWrap = document.getElementById('reply-template-select-wrap');
-        const noSigLabel = document.getElementById('reply-no-signature') ? document.getElementById('reply-no-signature').closest('label') : null;
+        const useSigEl = document.getElementById('reply-use-signature');
+        const sigLabel = useSigEl ? useSigEl.closest('label') : null;
         if (ticketReplyType === 'note') {
             textarea.placeholder = 'Kirjoita sisäinen muistiinpano...';
             sendBtn.textContent = 'Tallenna muistiinpano';
             sigPrev.style.display = 'none';
             if (metaFields) metaFields.style.display = 'none';
             if (tplWrap) tplWrap.style.display = 'none';
-            if (noSigLabel) noSigLabel.style.display = 'none';
+            if (sigLabel) sigLabel.style.display = 'none';
         } else {
             textarea.placeholder = 'Kirjoita vastaus...';
             sendBtn.textContent = 'Lähetä vastaus';
             if (metaFields) metaFields.style.display = '';
             if (tplWrap) tplWrap.style.display = '';
-            if (noSigLabel) noSigLabel.style.display = '';
-            // Näytä allekirjoitus jos on asetettu ja checkbox sallii
-            const noSigCheck = document.getElementById('reply-no-signature');
-            if (sigPrev.textContent.trim() && !(noSigCheck && noSigCheck.checked)) sigPrev.style.display = 'block';
+            if (sigLabel) sigLabel.style.display = '';
+            // Näytä allekirjoitus jos checkbox päällä
+            if (sigPrev.textContent.trim() && useSigEl && useSigEl.checked) sigPrev.style.display = 'block';
         }
     });
 });
@@ -1710,10 +1710,10 @@ document.getElementById('btn-send-reply').addEventListener('click', async () =>
         if (ticketReplyType !== 'note') {
             const mbSel = document.getElementById('reply-mailbox-select');
             const ccFld = document.getElementById('reply-cc');
-            const noSig = document.getElementById('reply-no-signature');
+            const useSig = document.getElementById('reply-use-signature');
             if (mbSel) payload.mailbox_id = mbSel.value;
             if (ccFld) payload.cc = ccFld.value.trim();
-            if (noSig && noSig.checked) payload.no_signature = true;
+            if (useSig && !useSig.checked) payload.no_signature = true;
         }
         await apiCall(action + ticketCompanyParam(), 'POST', payload);
         // Reload the detail view