Improve mobile reading layout and typography

Make classic text chapters easier to read on phones with responsive styles, collapsed sidebar groups, and less intrusive install prompts on doc pages.

Co-authored-by: Cursor <cursoragent@cursor.com>

.vitepress/sidebar.mts

@@ -85,7 +85,7 @@ export function generateSidebar(): Record<string, SidebarItem[]> {
   if (rootFiles.length > 0) {
     groups.push({
       text: '典籍',
-      collapsed: false,
+      collapsed: true,
       items: rootFiles.map((file) => ({
         text: titleFromFilename(file.name),
         link: toLink(file.name),
@@ -103,7 +103,7 @@ export function generateSidebar(): Record<string, SidebarItem[]> {
     if (items.length === 0) continue
     groups.push({
       text: dir.name,
-      collapsed: false,
+      collapsed: true,
       items,
     })
   }