fix: hide iframe before full load to avoid page flicker

Author: Piotr1215

docs/index.mdx

@@ -154,6 +154,10 @@ export const InlineSearch = () => {
       `;
       iframeDoc.head.appendChild(style);
 
+      // Show iframe now that CSS is injected (eliminates FOUC)
+      iframe.style.visibility = 'visible';
+      iframe.style.opacity = '1';
+
       // Intercept all link clicks and navigate parent window
       const handleLinkClick = (e) => {
         const link = e.target.closest('a');
@@ -187,6 +191,11 @@ export const InlineSearch = () => {
       });
     } catch (e) {
       console.error('Cannot inject styles into iframe:', e);
+      // Show iframe even on error to avoid permanent blank state
+      if (iframe) {
+        iframe.style.visibility = 'visible';
+        iframe.style.opacity = '1';
+      }
     }
   };
 
@@ -298,7 +307,10 @@ export const InlineSearch = () => {
             style={{
               width: '100%',
               height: '100%',
-              border: 'none'
+              border: 'none',
+              visibility: 'hidden',
+              opacity: '0',
+              transition: 'opacity 0.15s ease-in-out'
             }}
             title="Search Documentation"
           />