diff --git a/gauge-designer.html b/gauge-designer.html
index 6ef5480..9faef17 100644
--- a/gauge-designer.html
+++ b/gauge-designer.html
@@ -291,7 +291,7 @@
     </div>
     <div class="row">
       <label>Number font size</label>
-      <input type="range" id="numFontSize" min="1" max="8" value="3" step="0.5">
+      <input type="range" id="numFontSize" min="1" max="25" value="3" step="0.5">
       <span class="val" id="numFontSizeVal">3%</span>
     </div>
   </div>
@@ -363,7 +363,7 @@
     </div>
     <div class="row">
       <label>Title size %</label>
-      <input type="range" id="titleSize" min="2" max="15" value="6">
+      <input type="range" id="titleSize" min="2" max="30" value="6">
       <span class="val" id="titleSizeVal">6%</span>
     </div>
     <div class="row">
@@ -377,7 +377,7 @@
     </div>
     <div class="row">
       <label>Subtitle size %</label>
-      <input type="range" id="subtitleSize" min="1" max="10" value="3">
+      <input type="range" id="subtitleSize" min="1" max="25" value="3">
       <span class="val" id="subtitleSizeVal">3%</span>
     </div>
     <div class="row">
@@ -484,6 +484,10 @@
     <div class="hint" style="margin-top:6px;text-align:center">
       PDF prints at exact physical size.<br>Print at 100% — no scaling.
     </div>
+    <hr class="divider" style="margin-top:10px">
+    <button id="saveDesignBtn" class="secondary">Save Design (.json)</button>
+    <button id="loadDesignBtn" class="secondary">Load Design (.json)</button>
+    <input type="file" id="loadDesignInput" accept=".json" style="display:none">
   </div>
 </div>
 
@@ -1018,6 +1022,87 @@ $('exportPngBtn').addEventListener('click', () => {
   link.click();
 });
 
+// ── save / load design ────────────────────────────────────────────────────────
+$('saveDesignBtn').addEventListener('click', () => {
+  const data = { version: 1, gaugeMode, sweepDir, zones: JSON.parse(JSON.stringify(zones)) };
+  document.querySelectorAll('#sidebar input, #sidebar select').forEach(el => {
+    if (!el.id || el.type === 'file') return;
+    data[el.id] = el.type === 'checkbox' ? el.checked : el.value;
+  });
+  if (logoImg) {
+    data.logoDataUrl = logoImg.src;
+    data.logoFileName = $('logoFileName').textContent;
+  }
+  const blob = new Blob([JSON.stringify(data, null, 2)], { type: 'application/json' });
+  const a = document.createElement('a');
+  a.href = URL.createObjectURL(blob);
+  a.download = `${$('gaugeTitle').value || 'gauge'}-design.json`;
+  a.click();
+  URL.revokeObjectURL(a.href);
+});
+
+$('loadDesignBtn').addEventListener('click', () => $('loadDesignInput').click());
+
+$('loadDesignInput').addEventListener('change', e => {
+  const file = e.target.files[0];
+  if (!file) return;
+  const reader = new FileReader();
+  reader.onload = ev => {
+    let data;
+    try { data = JSON.parse(ev.target.result); } catch { alert('Invalid design file.'); return; }
+
+    // restore all inputs silently (no events yet)
+    document.querySelectorAll('#sidebar input, #sidebar select').forEach(el => {
+      if (!el.id || el.type === 'file' || !(el.id in data)) return;
+      if (el.type === 'checkbox') el.checked = data[el.id];
+      else el.value = data[el.id];
+    });
+
+    // update range display spans by firing input events on ranges
+    document.querySelectorAll('#sidebar input[type=range]').forEach(el => {
+      el.dispatchEvent(new Event('input'));
+    });
+
+    // restore gauge mode UI
+    gaugeMode = data.gaugeMode || 'standard';
+    if (gaugeMode === 'center') {
+      $('modeCtr').classList.add('active'); $('modeStd').classList.remove('active');
+      $('ctrFields').style.display = ''; $('stdFields').style.display = 'none';
+      $('ctrTickNote').style.display = ''; $('stdTickNote').style.display = 'none';
+      $('stdMajorInterval').style.display = 'none';
+    } else {
+      $('modeStd').classList.add('active'); $('modeCtr').classList.remove('active');
+      $('stdFields').style.display = ''; $('ctrFields').style.display = 'none';
+      $('stdTickNote').style.display = ''; $('ctrTickNote').style.display = 'none';
+      $('stdMajorInterval').style.display = '';
+    }
+
+    // restore sweep direction UI
+    sweepDir = data.sweepDir || 'cw';
+    if (sweepDir === 'ccw') {
+      $('dirCCW').classList.add('active'); $('dirCW').classList.remove('active');
+    } else {
+      $('dirCW').classList.add('active'); $('dirCCW').classList.remove('active');
+    }
+
+    // restore zones
+    zones = data.zones || [];
+    renderZones();
+
+    // restore logo
+    if (data.logoDataUrl) {
+      const img = new Image();
+      img.onload = () => { setLogo(img, data.logoFileName || 'logo'); drawGauge(); };
+      img.src = data.logoDataUrl;
+    } else {
+      clearLogo();
+      drawGauge();
+    }
+  };
+  reader.readAsText(file);
+  e.target.value = '';
+});
+
 // ── preview background toggle ─────────────────────────────────────────────────
 const previewArea = $('preview-area');