fix(mobile): bouton mode lecture visible uniquement fichier ouvert (BUG-016)

frontend/js/mobile-editor.js

@@ -603,6 +603,27 @@ function buildReadingControls() {
   document.body.appendChild(exit);
 }
 
+/** True when the BooksLM assistant panel is expanded on screen. */
+function isAssistantOpen() {
+  const panel = document.querySelector('.bookslm-panel');
+  return !!(panel && panel.classList.contains('open') && !panel.classList.contains('hidden'));
+}
+
+/**
+ * Show the floating reading-mode button only while a file is open and the
+ * assistant panel is closed. Without this guard the button floats above the
+ * full-screen mobile assistant and covers its send button.
+ *
+ * Called on init, whenever the content area changes and when the assistant
+ * opens/closes.
+ */
+export function updateReadingButtonVisibility() {
+  const btn = document.getElementById('me-reading-btn');
+  if (!btn) return;
+  const fileOpen = !!state.currentPath;
+  btn.hidden = !fileOpen || isAssistantOpen();
+}
+
 // ── Swipe gestures ─────────────────────────────────────────────────────────
 
 function initSwipeGestures() {
@@ -659,6 +680,19 @@ export function initMobileEditor() {
   buildReadingControls();
   initSwipeGestures();
 
+  // Keep the reading button in sync with the current view: visible only when
+  // a file is open and the assistant is closed.
+  updateReadingButtonVisibility();
+  document.addEventListener('bookslm:opened', updateReadingButtonVisibility);
+  document.addEventListener('bookslm:closed', updateReadingButtonVisibility);
+  const readingArea = document.getElementById('content-area');
+  if (readingArea && typeof MutationObserver !== 'undefined') {
+    new MutationObserver(updateReadingButtonVisibility).observe(readingArea, {
+      childList: true,
+      subtree: true,
+    });
+  }
+
   const bodyEl = document.getElementById('editor-body');
   if (bodyEl) {
     initPinchZoom(bodyEl);

frontend/style.css

@@ -9577,6 +9577,10 @@ body.bookslm-resizing { cursor: ew-resize; user-select: none; }
 .me-reading-exit {
   display: none;
 }
+/* Author `display: flex` would otherwise win over the `[hidden]` attribute. */
+.me-reading-btn[hidden] {
+  display: none;
+}
 
 @media (max-width: 768px) {
   .me-reading-btn {