diff --git a/index.html b/index.html
index 993b72b..a2ccb7f 100644
--- a/index.html
+++ b/index.html
@@ -52,7 +52,7 @@
         <br>
         <button type="button" class="inline-flex pure-button pure-button-primary" id="send">
             <span class="text">Open</span>
-            <span class="icon spin hidden">
+            <span class="icon spin" hidden>
                 <svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="icon icon-tabler icons-tabler-outline icon-tabler-loader">
                     <path stroke="none" d="M0 0h24v24H0z" fill="none"/>
                     <path d="M12 6l0 -3" />
@@ -231,13 +231,13 @@ $$$('#send', 'click', async (e) => {
         case 'STANDBY':
             Connection.send('RESUME');
             $('#send > span.text').innerText = 'Pause';
-            $('#send > span.icon').classList.remove('hidden');
+            $('#send > span.icon').removeAttribute('hidden');
             $('#send').disabled = true;
             break;
         case 'RUNNING':
             Connection.send('ONHOLD');
             $('#send > span.text').innerText = 'Resume';
-            $('#send > span.icon').classList.add('hidden');
+            $('#send > span.icon').setAttribute('hidden', '');
             $('#send').disabled = true;
             break;
         case 'READY':
@@ -268,7 +268,7 @@ $$$('#send', 'click', async (e) => {
             Timer.setTimestamp(true);
 
             $('#send > span.text').innerText = 'Pause';
-            $('#send > span.icon').classList.remove('hidden');
+            $('#send > span.icon').removeAttribute('hidden');
             $('#skip').disabled = false;
             break;
         default:
@@ -283,7 +283,7 @@ $$$('#send', 'click', async (e) => {
                         }
                     ]
                 };
-                $('#send > span.icon').classList.remove('hidden');
+                $('#send > span.icon').removeAttribute('hidden');
                 let [handle] = await showOpenFilePicker(PickerOptions);
                 let file = await handle.getFile();
 
@@ -303,7 +303,7 @@ $$$('#send', 'click', async (e) => {
                 $('#cancel').disabled = false;
                 $('#send').disabled = true;
             } finally {
-                $('#send > span.icon').classList.add('hidden');
+                $('#send > span.icon').setAttribute('hidden', '');
             }
     }
 });
@@ -490,7 +490,7 @@ function main(url, parameters, locales) {
                     case 'FAILED':
                         Status = 'STANDBY';
                         $('#send > span.text').innerText = 'Resume';
-                        $('#send > span.icon').classList.add('hidden');
+                        $('#send > span.icon').setAttribute('hidden', '');
                         Timer.setTimedelta();
                         break;
                     case 'FINISH':
@@ -499,7 +499,7 @@ function main(url, parameters, locales) {
                     case 'CANCEL':
                         Status = null;
                         $('#send > span.text').innerText = 'Open';
-                        $('#send > span.icon').classList.add('hidden');
+                        $('#send > span.icon').setAttribute('hidden', '');
                         $('#cancel').disabled = true;
                         $('#skip').disabled = true;
 
@@ -590,10 +590,6 @@ label {
     color: orangered;
 }
 
-.hidden {
-    display: none;
-}
-
 .gaps {
     row-gap: 0.4em;
 }