Require key, instrument, tuning

app.js

@@ -504,6 +504,7 @@ function openAdd() {
   editingTuneId         = null;
   editingEntryId        = null;
   editingOriginalRefIds = [];
+  setTuneError('');
   $('modal-title').textContent = 'Add tune';
   tuneForm.reset();
   refsList.innerHTML = '';
@@ -659,11 +660,43 @@ function addRefRow(link = '', site = '', refId = null, siteId = null, initialMus
 
 // ── Save ──────────────────────────────────────────────────────
 $('btn-save-tune').addEventListener('click', saveTune);
-$('btn-cancel').addEventListener('click', () => tuneModal.close());
+$('btn-cancel').addEventListener('click', () => { setTuneError(''); tuneModal.close(); });
+
+function setTuneError(msg) {
+  const el = $('tune-error');
+  el.textContent = msg;
+  el.hidden = !msg;
+}
 
 async function saveTune() {
   const f = tuneForm.elements;
 
+  // Validate required fields
+  const keyVal    = f.key.value.trim();
+  const tuningVal = f.inst_tuning.value.trim();
+
+  if (!keyVal) {
+    setTuneError('Key is required.');
+    f.key.focus();
+    return;
+  }
+  if (!instrumentSelect.value) {
+    setTuneError('Instrument is required.');
+    instrumentSelect.focus();
+    return;
+  }
+  if (!tuningVal) {
+    setTuneError('Tuning is required.');
+    f.inst_tuning.focus();
+    return;
+  }
+  if (!resolveTuningId(tuningVal)) {
+    setTuneError(`Tuning "${tuningVal}" not found — use + to add it first.`);
+    f.inst_tuning.focus();
+    return;
+  }
+  setTuneError('');
+
   const tuneBody = {
     name:      f.name.value  || null,
     key:       f.key.value   || null,

index.html

@@ -154,6 +154,7 @@
         <button type="button" id="btn-add-ref">+ reference</button>
       </div>
 
+      <p id="tune-error" class="modal-error" hidden></p>
       <div class="modal-actions">
         <button type="button" id="btn-delete-tune" class="btn-danger" hidden>Delete tune</button>
         <button type="button" id="btn-edit-notes" hidden>📝 Notes</button>

style.css

@@ -305,6 +305,8 @@ fieldset label {
   font-size: .85rem;
 }
 
+fieldset input[type="checkbox"] { justify-self: start; }
+
 fieldset input[type="text"],
 fieldset input[type="date"],
 fieldset select {
@@ -357,6 +359,8 @@ fieldset.active .fs-body { display: contents; }
 
 .btn-danger { background: var(--accent); }
 
+.modal-error { color: #eb5757; font-size: .82rem; margin: .3rem 0 0; }
+
 .note-row {
   display: flex;
   align-items: center;