fix: polish Pi-hole connection states

internal/web/static/app.js

@@ -198,6 +198,18 @@
     syncDirtyState();
   }
 
+  for (const details of document.querySelectorAll('details[data-scroll-page-end]')) {
+    details.addEventListener('toggle', () => {
+      if (!details.open) return;
+      window.requestAnimationFrame(() => {
+        window.scrollTo({
+          top: document.documentElement.scrollHeight,
+          behavior: window.matchMedia('(prefers-reduced-motion: reduce)').matches ? 'auto' : 'smooth',
+        });
+      });
+    });
+  }
+
   const copyButtons = document.querySelectorAll('[data-copy-target]');
   for (const button of copyButtons) {
     button.addEventListener('click', async () => {

internal/web/static/styles.css

@@ -256,10 +256,9 @@ h3 { margin-bottom: 2px; font-size: 14px; line-height: 1.35; }
 .pihole-connection-error { margin-bottom: 18px; padding: 12px; border: 1px solid #efc7ce; border-left: 3px solid #a4121a; border-radius: var(--radius-sm); background: #fff8f9; }
 .pihole-connection-error strong { color: var(--danger); font-size: 11px; }
 .pihole-connection-error p { margin: 3px 0 0; color: #865764; font-size: 10px; overflow-wrap: anywhere; }
-.pihole-connect-panel { max-width: 720px; margin-top: 20px; border-top: 3px solid #a4121a; scroll-margin-top: 18px; }
+.pihole-connect-stage { display: grid; min-height: clamp(390px, calc(100vh - 245px), 640px); place-items: center; }
+.pihole-connect-panel { width: min(560px, 100%); border-top: 3px solid #a4121a; }
 .pihole-api-badge { padding: 4px 7px; border-radius: 4px; background: #fff0f1; color: #98131b; font-family: var(--mono); font-size: 9px; font-weight: 800; }
-.pihole-empty { margin-bottom: 18px; }
-.pihole-empty-icon { border-color: #e4b7ba; background: #fff2f3; color: #9d1018; }
 
 .stacked-form { display: grid; gap: 13px; }
 .wide-form { width: 100%; max-width: 850px; }
@@ -420,6 +419,7 @@ input:focus, textarea:focus, select:focus { border-color: var(--accent); box-sha
   .error-item { grid-template-columns: 26px minmax(0,1fr); }
   .error-item > a { grid-column: 2; }
   .pihole-action-grid { grid-template-columns: 1fr; }
+  .pihole-connect-stage { min-height: 0; }
 }
 
 @media (prefers-reduced-motion: reduce) {