diff --git a/iframe.html b/iframe.html
index c171ab3..0cef0e3 100644
--- a/iframe.html
+++ b/iframe.html
@@ -1659,6 +1659,11 @@
             color: white;
         }
 
+        /* Hidden unit select for compatibility */
+        .dog-calculator-unit-select-hidden {
+            display: none;
+        }
+
         /* Mobile responsive adjustments for inline unit selector */
         @media (max-width: 576px) {
             .dog-calculator-result-item {
@@ -1920,7 +1925,7 @@
                     </div>
 
                     <!-- Hidden select for compatibility -->
-                    <select id="unit" style="display: none;" aria-describedby="unitHelp">
+                    <select id="unit" class="dog-calculator-unit-select-hidden" aria-describedby="unitHelp">
                         <option value="g">grams (g)</option>
                         <option value="kg">kilograms (kg)</option>
                         <option value="oz">ounces (oz)</option>