diff --git a/articles/index.html b/articles/index.html
index 638e8b5..08aca40 100644
--- a/articles/index.html
+++ b/articles/index.html
@@ -4,7 +4,6 @@
 <meta name="viewport" content="width=device-width,initial-scale=1">
 <title>Mini Articles</title>
 <style>
-/* Tiny, readable defaults */
 *{box-sizing:border-box}html,body{height:100%}body{margin:0;font:16px/1.4 system-ui,-apple-system,Segoe UI,Roboto,Ubuntu,Cantarell,'Helvetica Neue',Arial,sans-serif;color:#222;background:#fff}
 header{display:flex;gap:.5rem;align-items:center;justify-content:space-between;padding:.5rem .75rem;border-bottom:1px solid #ddd;position:sticky;top:0;background:#fff}
 header h1{margin:0;font-size:1.1rem}
@@ -12,7 +11,6 @@ header nav{display:flex;gap:.5rem}
 button, input[type=file]{font:inherit}
 main{max-width:960px;margin:0 auto;padding:1rem}
 .hidden{display:none!important}
-section.hidden{display:none!important}
 .grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(180px,1fr));gap:.75rem}
 .card{border:1px solid #ddd;border-radius:.5rem;overflow:hidden;background:#fff;cursor:pointer;display:flex;flex-direction:column}
 .card img{width:100%;height:120px;object-fit:cover;display:block}
@@ -27,11 +25,9 @@ article img, article video{max-width:100%;height:auto;display:block;margin:.5rem
 article h1{margin:.25rem 0 .5rem;font-size:1.6rem}
 .controls{display:flex;gap:.5rem;flex-wrap:wrap;margin:.5rem 0}
 .small{font-size:.85rem;color:#666}
-/* Loading indicator */
 #loading{display:flex;align-items:center;gap:.5rem;margin:0 0 1rem}
 .spinner{width:16px;height:16px;border:2px solid #ccc;border-top-color:#333;border-radius:50%;display:inline-block;animation:spin 1s linear infinite}
 @keyframes spin{to{transform:rotate(360deg)}}
-/* Focused reading mode: keep header headline, hide nav and extras */
 .reading header nav{display:none}
 .reading #delBtn,.reading #dateInfo{display:none}
 </style>
@@ -241,6 +237,8 @@ article h1{margin:.25rem 0 .5rem;font-size:1.6rem}
     show(listV);
     setLoading(false);
   })();
+
+  navigator.serviceWorker&&navigator.serviceWorker.register('/sw.js').catch(()=>{});
 })();
 </script>
 </html>
diff --git a/articles/sw.js b/articles/sw.js
new file mode 100644
index 0000000..7842990
--- /dev/null
+++ b/articles/sw.js
@@ -0,0 +1,18 @@
+// Minimal image cache-first service worker
+const C = 'articles-img-v1';
+self.addEventListener('install', e => self.skipWaiting());
+self.addEventListener('activate', e => e.waitUntil(self.clients.claim()));
+self.addEventListener('fetch', e => {
+  const req = e.request;
+  const u = new URL(req.url);
+  const isImg = req.destination === 'image' || u.pathname.startsWith('/uploads/');
+  if (!isImg || req.method !== 'GET') return;
+  e.respondWith((async () => {
+    const cache = await caches.open(C);
+    const hit = await cache.match(req, { ignoreVary: true, ignoreSearch: false });
+    if (hit) return hit;
+    const res = await fetch(req);
+    if (res && res.ok) cache.put(req, res.clone());
+    return res;
+  })());
+});