diff --git a/website/public/debug/lang/mix.html b/website/public/debug/lang/mix.html
index ccf158a..18d83c5 100644
--- a/website/public/debug/lang/mix.html
+++ b/website/public/debug/lang/mix.html
@@ -52,19 +52,33 @@
             />
           </div>
 
-          <div class="pt-5 flex gap-2">
-            <button
-              id="shareBtn"
-              class="px-4 py-1.5 text-sm font-medium text-white bg-blue-600 rounded hover:bg-blue-700 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:ring-offset-2 focus:ring-offset-gray-900 transition-all"
-            >
-              Share
-            </button>
-            <button
-              id="resetBtn"
-              class="px-4 py-1.5 text-sm font-medium text-white bg-gray-700 rounded hover:bg-gray-600 focus:outline-none focus:ring-2 focus:ring-gray-500 focus:ring-offset-2 focus:ring-offset-gray-900 transition-all"
-            >
-              Reset
-            </button>
+          <div class="flex flex-col gap-2">
+            <div class="flex items-center gap-2">
+              <label
+                class="flex items-center gap-2 text-xs text-gray-300 cursor-pointer whitespace-nowrap"
+              >
+                <input
+                  type="checkbox"
+                  id="showDifferencesRed"
+                  class="w-4 h-4 text-blue-600 bg-gray-700 border-gray-600 rounded focus:ring-blue-500 focus:ring-2"
+                />
+                <span>Show differences red</span>
+              </label>
+            </div>
+            <div class="flex gap-2">
+              <button
+                id="shareBtn"
+                class="px-4 py-1.5 text-sm font-medium text-white bg-blue-600 rounded hover:bg-blue-700 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:ring-offset-2 focus:ring-offset-gray-900 transition-all"
+              >
+                Share
+              </button>
+              <button
+                id="resetBtn"
+                class="px-4 py-1.5 text-sm font-medium text-white bg-gray-700 rounded hover:bg-gray-600 focus:outline-none focus:ring-2 focus:ring-gray-500 focus:ring-offset-2 focus:ring-offset-gray-900 transition-all"
+              >
+                Reset
+              </button>
+            </div>
           </div>
         </div>
       </div>
diff --git a/website/public/debug/lang/mix.js b/website/public/debug/lang/mix.js
index ed98463..944cbb9 100644
--- a/website/public/debug/lang/mix.js
+++ b/website/public/debug/lang/mix.js
@@ -15,6 +15,7 @@ const line2Input = document.getElementById('line2')
 const langInput = document.getElementById('lang')
 const line1ExprInput = document.getElementById('line1-expr')
 const line2ExprInput = document.getElementById('line2-expr')
+const showDifferencesRedCheckbox = document.getElementById('showDifferencesRed')
 
 map.on('load', () => {
   const params = new URLSearchParams(window.location.search)
@@ -22,7 +23,7 @@ map.on('load', () => {
   // Set defaults if no params present
   if (!params.has('line1') && !params.has('line2') && !params.has('lang')) {
     const url = new URL(window.location)
-    url.searchParams.set('line1', 'colon,underscore,name,latin')
+    url.searchParams.set('line1', 'colon,underscore,latin,name')
     url.searchParams.set('line2', 'nonlatin')
     url.searchParams.set('lang', 'en')
     window.history.replaceState({}, '', url)
@@ -50,6 +51,7 @@ function initializeInputListeners() {
   line1Input.addEventListener('input', handleInput)
   line2Input.addEventListener('input', handleInput)
   langInput.addEventListener('input', handleInput)
+  showDifferencesRedCheckbox.addEventListener('change', handleInput)
 }
 
 function initializeModal() {
@@ -82,7 +84,7 @@ function initializeResetButton() {
 // ============================================
 
 function applyConfiguration() {
-  const { line1, line2, lang } = parseParams()
+  const { line1, line2, lang, showDifferencesRed } = parseParams()
 
   if (!map.getStyle()) return
 
@@ -92,16 +94,18 @@ function applyConfiguration() {
     line1Config: line1 ?? '',
     line2Config: line2 ?? '',
     langCode: lang,
+    showDifferencesRed,
   })
   map.setStyle(style, { diff: true })
   updateExpressionDisplays()
 }
 
 function syncInputsFromParams() {
-  const { line1, line2, lang } = parseParams()
+  const { line1, line2, lang, showDifferencesRed } = parseParams()
   line1Input.value = line1 ?? ''
   line2Input.value = line2 ?? ''
   langInput.value = lang ?? ''
+  showDifferencesRedCheckbox.checked = showDifferencesRed
 }
 
 function updateParamsFromInputs() {
@@ -110,6 +114,12 @@ function updateParamsFromInputs() {
   params.set('line2', line2Input.value)
   params.set('lang', langInput.value)
 
+  if (showDifferencesRedCheckbox.checked) {
+    params.set('showDifferencesRed', '1')
+  } else {
+    params.delete('showDifferencesRed')
+  }
+
   const queryString = params.toString()
   const hash = window.location.hash
   const newUrl = `${window.location.pathname}?${queryString}${hash}`
@@ -132,7 +142,7 @@ function updateExpressionDisplays() {
 // 4. STYLE MODIFICATION
 // ============================================
 
-function modifyStyle({ style, line1Config, line2Config, langCode }) {
+function modifyStyle({ style, line1Config, line2Config, langCode, showDifferencesRed }) {
   for (const layer of style.layers) {
     if (layer.source !== 'openmaptiles') continue
     if (!layer.layout) continue
@@ -157,6 +167,22 @@ function modifyStyle({ style, line1Config, line2Config, langCode }) {
     } else {
       layer.layout['text-field'] = ['get', 'name']
     }
+
+    // Apply red color when differences should be shown
+    if (showDifferencesRed && line1Expr && line2Expr) {
+      if (!layer.paint) layer.paint = {}
+      layer.paint['text-color'] = [
+        'case',
+        ['!=', line1Expr, line2Expr],
+        '#ff0000', // Red when different
+        '#000000', // Black when same
+      ]
+    } else {
+      // Reset to default color if checkbox is unchecked
+      if (layer.paint && layer.paint['text-color']) {
+        delete layer.paint['text-color']
+      }
+    }
   }
 }
 
@@ -181,6 +207,7 @@ function parseParams() {
     line1: params.get('line1'),
     line2: params.get('line2'),
     lang: params.get('lang') || 'en',
+    showDifferencesRed: params.has('showDifferencesRed'),
   }
 }