Hide the sidebar when collapsed to prevent browser search to find text from it

src/front-end/css/chrome.css

@@ -530,7 +530,6 @@ html:not(.sidebar-resizing) .sidebar {
 /* sidebar-hidden */
 #sidebar-toggle-anchor:not(:checked) ~ .sidebar {
     transform: translateX(calc(0px - var(--sidebar-width) - var(--sidebar-resize-indicator-width)));
-    z-index: -1;
 }
 [dir=rtl] #sidebar-toggle-anchor:not(:checked) ~ .sidebar {
     transform: translateX(calc(var(--sidebar-width) + var(--sidebar-resize-indicator-width)));

src/front-end/js/book.js

@@ -519,10 +519,30 @@ aria-label="Show hidden lines"></button>';
     const sidebar = document.getElementById('sidebar');
     const sidebarLinks = document.querySelectorAll('#sidebar a');
     const sidebarToggleButton = document.getElementById('sidebar-toggle');
-    const sidebarToggleAnchor = document.getElementById('sidebar-toggle-anchor');
     const sidebarResizeHandle = document.getElementById('sidebar-resize-handle');
+    const sidebarCheckbox = document.getElementById('sidebar-toggle-anchor');
     let firstContact = null;
 
+
+    /* Because we cannot change the `display` using only CSS after/before the transition, we
+       need JS to do it. We change the display to prevent the browsers search to find text inside
+       the collapsed sidebar. */
+    if (!document.documentElement.classList.contains('sidebar-visible')) {
+        sidebar.style.display = 'none';
+    }
+    sidebar.addEventListener('transitionend', () => {
+        /* We only change the display to "none" if we're collapsing the sidebar. */
+        if (!sidebarCheckbox.checked) {
+            sidebar.style.display = 'none';
+        }
+    });
+    sidebarToggleButton.addEventListener('click', () => {
+        /* To allow the sidebar expansion animation, we first need to put back the display. */
+        if (!sidebarCheckbox.checked) {
+            sidebar.style.display = '';
+        }
+    });
+
     function showSidebar() {
         body.classList.add('sidebar-visible');
         Array.from(sidebarLinks).forEach(function(link) {
@@ -552,8 +572,8 @@ aria-label="Show hidden lines"></button>';
     }
 
     // Toggle sidebar
-    sidebarToggleAnchor.addEventListener('change', function sidebarToggle() {
+    sidebarCheckbox.addEventListener('change', function sidebarToggle() {
-        if (sidebarToggleAnchor.checked) {
+        if (sidebarCheckbox.checked) {
             const current_width = parseInt(
                 document.documentElement.style.getPropertyValue('--sidebar-target-width'), 10);
             if (current_width < 150) {
@@ -577,7 +597,7 @@ aria-label="Show hidden lines"></button>';
         if (pos < 20) {
             hideSidebar();
         } else {
-            if (body.classList.contains('sidebar-hidden')) {
+            if (!body.classList.contains('sidebar-visible')) {
                 showSidebar();
             }
             pos = Math.min(pos, window.innerWidth - 100);

src/front-end/templates/index.hbs

@@ -116,10 +116,13 @@
                 sidebar = sidebar || 'visible';
             } else {
                 sidebar = 'hidden';
+                sidebar_toggle.checked = false;
+            }
+            if (sidebar === 'visible') {
+                sidebar_toggle.checked = true;
+            } else {
+                html.classList.remove('sidebar-visible');
             }
-            sidebar_toggle.checked = sidebar === 'visible';
-            html.classList.remove('sidebar-visible');
-            html.classList.add("sidebar-" + sidebar);
         </script>
 
         <nav id="sidebar" class="sidebar" aria-label="Table of contents">