fix: reader header auto-hide, keyboard null guard, active thumb box-shadow

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/static/js/reader.js

@@ -2,7 +2,7 @@
 'use strict';
 
 document.addEventListener('DOMContentLoaded', () => {
-  const { startPage, totalPages } = window.readerConfig || { startPage: 1, totalPages: 1 };
+  const { startPage } = window.readerConfig || { startPage: 1 };
 
   // Elements
   // #readerContent is the actual scroll container (overflow-y: auto)
@@ -122,7 +122,10 @@ document.addEventListener('DOMContentLoaded', () => {
   }
 
   // Show header on mouse move
-  document.addEventListener('mousemove', showHeader);
+  document.addEventListener('mousemove', () => {
+    showHeader();
+    scheduleHideHeader();
+  });
 
   // -------------------------
   // Jump to page
@@ -185,6 +188,7 @@ document.addEventListener('DOMContentLoaded', () => {
   // -------------------------
   document.addEventListener('keydown', (e) => {
     if (e.target.tagName === 'INPUT' || e.target.tagName === 'SELECT') return;
+    if (!readerContent) return;
     showHeader();
 
     switch (e.key) {

app/static/style.css

@@ -2542,6 +2542,7 @@ body.select-mode .gallery-infinite-container {
   position: relative;
   border-radius: 6px;
   overflow: hidden;
+  transition: opacity 0.2s ease;
   cursor: pointer;
   border: 2px solid transparent;
   transition: all 0.2s ease;
@@ -2636,12 +2637,11 @@ body.select-mode .gallery-infinite-container {
 
 /* Active nav thumbnail */
 .reader-nav-thumb.active {
-  border-left: 3px solid var(--btn-primary);
+  box-shadow: inset 3px 0 0 var(--btn-primary);
   opacity: 1;
 }
 .reader-nav-thumb:not(.active) {
   opacity: 0.5;
-  transition: opacity 0.2s ease;
 }
 .reader-nav-thumb:hover {
   opacity: 1;