fix(ui): Harmonize spacing in library sub-pages

- Removed space-y-6 container wrapper
- Added explicit mb-6 margins on breadcrumb, h1, Card, and h2 elements
- Consistent spacing approach across all library pages

apps/backoffice/app/libraries/[id]/books/page.tsx

@@ -0,0 +1,95 @@
+import { fetchLibraries, fetchBooks, getBookCoverUrl, LibraryDto, BookDto } from "../../../../lib/api";
+import { BooksGrid, EmptyState } from "../../../components/BookCard";
+import { Card, Badge, Button, CursorPagination } from "../../../components/ui";
+import Link from "next/link";
+import { notFound } from "next/navigation";
+
+export const dynamic = "force-dynamic";
+
+export default async function LibraryBooksPage({
+  params,
+  searchParams
+}: {
+  params: Promise<{ id: string }>;
+  searchParams: Promise<{ [key: string]: string | string[] | undefined }>;
+}) {
+  const { id } = await params;
+  const searchParamsAwaited = await searchParams;
+  const cursor = typeof searchParamsAwaited.cursor === "string" ? searchParamsAwaited.cursor : undefined;
+  const series = typeof searchParamsAwaited.series === "string" ? searchParamsAwaited.series : undefined;
+  const limit = typeof searchParamsAwaited.limit === "string" ? parseInt(searchParamsAwaited.limit) : 20;
+  
+  const [library, booksPage] = await Promise.all([
+    fetchLibraries().then(libs => libs.find(l => l.id === id)),
+    fetchBooks(id, series, cursor, limit).catch(() => ({ 
+      items: [] as BookDto[], 
+      next_cursor: null 
+    }))
+  ]);
+
+  if (!library) {
+    notFound();
+  }
+
+  const books = booksPage.items.map(book => ({
+    ...book,
+    coverUrl: getBookCoverUrl(book.id)
+  }));
+  const nextCursor = booksPage.next_cursor;
+  
+  const seriesDisplayName = series === "unclassified" ? "Unclassified" : series;
+  const hasNextPage = !!nextCursor;
+  const hasPrevPage = !!cursor;
+
+  return (
+    <>
+      <div className="mb-6">
+        <Link href="/libraries" className="text-sm text-muted hover:text-primary transition-colors">← Back to libraries</Link>
+      </div>
+
+      <h1 className="text-3xl font-bold text-foreground flex items-center gap-3 mb-6">
+        <svg className="w-8 h-8 text-success" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 6.253v13m0-13C10.832 5.477 9.246 5 7.5 5S4.168 5.477 3 6.253v13C4.168 18.477 5.754 18 7.5 18s3.332.477 4.5 1.253m0-13C13.168 5.477 14.754 5 16.5 5c1.747 0 3.332.477 4.5 1.253v13C19.832 18.477 18.247 18 16.5 18c-1.746 0-3.332.477-4.5 1.253" /></svg>
+        {library.name}
+      </h1>
+      
+      <Card className="mb-6">
+        <div className="flex flex-wrap items-center gap-3 text-sm">
+          <code className="text-xs font-mono text-muted bg-muted/10 px-2 py-1 rounded">{library.root_path}</code>
+          <span className="text-muted">|</span>
+          <span className="text-foreground">{library.book_count} book{library.book_count !== 1 ? 's' : ''}</span>
+          <span className="text-muted">|</span>
+          <Badge variant={library.enabled ? "success" : "muted"}>
+            {library.enabled ? "Enabled" : "Disabled"}
+          </Badge>
+        </div>
+      </Card>
+
+      <div className="flex items-center gap-4 mb-6">
+        <h2 className="text-xl font-semibold text-foreground">
+          {series ? `Books in "${seriesDisplayName}"` : "All Books"}
+        </h2>
+        {series && (
+          <Link href={`/libraries/${id}/books`} className="text-sm text-primary hover:text-primary/80">
+            View all
+          </Link>
+        )}
+      </div>
+
+      {books.length > 0 ? (
+        <>
+          <BooksGrid books={books} />
+          
+          <CursorPagination
+            hasNextPage={hasNextPage}
+            hasPrevPage={hasPrevPage}
+            pageSize={limit}
+            currentCount={books.length}
+            nextCursor={nextCursor}
+          />
+        </>
+      ) : (
+        <EmptyState message={series ? `No books in series "${seriesDisplayName}"` : "No books in this library yet"} />
+      )}
+    </>
+  );
+}

apps/backoffice/app/libraries/[id]/series/page.tsx

@@ -0,0 +1,87 @@
+import { fetchLibraries, fetchSeries, getBookCoverUrl, LibraryDto, SeriesDto } from "../../../../lib/api";
+import Image from "next/image";
+import Link from "next/link";
+import { notFound } from "next/navigation";
+import { Card, Badge } from "../../../components/ui";
+
+export const dynamic = "force-dynamic";
+
+export default async function LibrarySeriesPage({
+  params
+}: {
+  params: Promise<{ id: string }>;
+}) {
+  const { id } = await params;
+  
+  const [library, series] = await Promise.all([
+    fetchLibraries().then(libs => libs.find(l => l.id === id)),
+    fetchSeries(id).catch(() => [] as SeriesDto[])
+  ]);
+
+  if (!library) {
+    notFound();
+  }
+
+  return (
+    <>
+      <div className="mb-6">
+        <Link href="/libraries" className="text-sm text-muted hover:text-primary transition-colors">← Back to libraries</Link>
+      </div>
+
+      <h1 className="text-3xl font-bold text-foreground flex items-center gap-3 mb-6">
+        <svg className="w-8 h-8 text-primary" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M19 11H5m14 0a2 2 0 012 2v6a2 2 0 01-2 2H5a2 2 0 01-2-2v-6a2 2 0 012-2m14 0V9a2 2 0 00-2-2M5 11V9a2 2 0 012-2m0 0V5a2 2 0 012-2h6a2 2 0 012 2v2M7 7h10" /></svg>
+        {library.name}
+      </h1>
+      
+      <Card className="mb-6">
+        <div className="flex flex-wrap items-center gap-3 text-sm">
+          <code className="text-xs font-mono text-muted bg-muted/10 px-2 py-1 rounded">{library.root_path}</code>
+          <span className="text-muted">|</span>
+          <span className="text-foreground">{library.book_count} book{library.book_count !== 1 ? 's' : ''}</span>
+          <span className="text-muted">|</span>
+          <Badge variant={library.enabled ? "success" : "muted"}>
+            {library.enabled ? "Enabled" : "Disabled"}
+          </Badge>
+        </div>
+      </Card>
+
+      <h2 className="text-xl font-semibold text-foreground mb-6">Series ({series.length})</h2>
+
+      {series.length > 0 ? (
+        <div className="grid grid-cols-2 sm:grid-cols-3 md:grid-cols-4 lg:grid-cols-5 gap-6">
+          {series.map((s) => (
+            <Link 
+              key={s.name} 
+              href={`/libraries/${id}/books?series=${encodeURIComponent(s.name)}`}
+              className="group"
+            >
+              <div className="bg-card rounded-xl shadow-soft border border-line overflow-hidden hover:shadow-card transition-shadow">
+                <div className="aspect-[2/3] relative bg-muted/10">
+                  <Image
+                    src={getBookCoverUrl(s.first_book_id)}
+                    alt={`Cover of ${s.name}`}
+                    fill
+                    className="object-cover"
+                    unoptimized
+                  />
+                </div>
+                <div className="p-3">
+                  <h3 className="font-medium text-foreground truncate text-sm" title={s.name}>
+                    {s.name === "unclassified" ? "Unclassified" : s.name}
+                  </h3>
+                  <p className="text-xs text-muted mt-1">
+                    {s.book_count} book{s.book_count !== 1 ? 's' : ''}
+                  </p>
+                </div>
+              </div>
+            </Link>
+          ))}
+        </div>
+      ) : (
+        <div className="text-center py-12 text-muted">
+          <p>No series found in this library</p>
+        </div>
+      )}
+    </>
+  );
+}

apps/backoffice/app/libraries/page.tsx

@@ -0,0 +1,181 @@
+import { revalidatePath } from "next/cache";
+import Link from "next/link";
+import { listFolders, createLibrary, deleteLibrary, fetchLibraries, fetchSeries, scanLibrary, LibraryDto, FolderItem } from "../../lib/api";
+import { LibraryActions } from "../components/LibraryActions";
+import { Card, CardHeader, Button, Badge, FormField, FormInput, FormSelect, FormRow } from "../components/ui";
+
+export const dynamic = "force-dynamic";
+
+function formatNextScan(nextScanAt: string | null): string {
+  if (!nextScanAt) return "-";
+  const date = new Date(nextScanAt);
+  const now = new Date();
+  const diff = date.getTime() - now.getTime();
+  
+  if (diff < 0) return "Due now";
+  if (diff < 60000) return "< 1 min";
+  if (diff < 3600000) return `${Math.floor(diff / 60000)}m`;
+  if (diff < 86400000) return `${Math.floor(diff / 3600000)}h`;
+  return `${Math.floor(diff / 86400000)}d`;
+}
+
+export default async function LibrariesPage() {
+  const [libraries, folders] = await Promise.all([
+    fetchLibraries().catch(() => [] as LibraryDto[]),
+    listFolders().catch(() => [] as FolderItem[])
+  ]);
+
+  const seriesCounts = await Promise.all(
+    libraries.map(async (lib) => {
+      try {
+        const series = await fetchSeries(lib.id);
+        return { id: lib.id, count: series.length };
+      } catch {
+        return { id: lib.id, count: 0 };
+      }
+    })
+  );
+  
+  const seriesCountMap = new Map(seriesCounts.map(s => [s.id, s.count]));
+
+  async function addLibrary(formData: FormData) {
+    "use server";
+    const name = formData.get("name") as string;
+    const rootPath = formData.get("root_path") as string;
+    if (name && rootPath) {
+      await createLibrary(name, rootPath);
+      revalidatePath("/libraries");
+    }
+  }
+
+  async function removeLibrary(formData: FormData) {
+    "use server";
+    const id = formData.get("id") as string;
+    await deleteLibrary(id);
+    revalidatePath("/libraries");
+  }
+
+  async function scanLibraryAction(formData: FormData) {
+    "use server";
+    const id = formData.get("id") as string;
+    await scanLibrary(id);
+    revalidatePath("/libraries");
+    revalidatePath("/jobs");
+  }
+
+  async function scanLibraryFullAction(formData: FormData) {
+    "use server";
+    const id = formData.get("id") as string;
+    await scanLibrary(id, true);
+    revalidatePath("/libraries");
+    revalidatePath("/jobs");
+  }
+
+  return (
+    <>
+      <h1 className="text-3xl font-bold text-foreground mb-6 flex items-center gap-3">
+        <svg className="w-8 h-8 text-primary" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M3 7v10a2 2 0 002 2h14a2 2 0 002-2V9a2 2 0 00-2-2h-6l-2-2H5a2 2 0 00-2 2z" /></svg>
+        Libraries
+      </h1>
+      
+      {/* Add Library Form */}
+      <Card className="mb-6">
+        <CardHeader title="Add New Library" />
+        <form action={addLibrary}>
+          <FormRow>
+            <FormField>
+              <FormInput name="name" placeholder="Library name" required />
+            </FormField>
+            <FormField>
+              <FormSelect name="root_path" required defaultValue="">
+                <option value="" disabled>Select folder...</option>
+                {folders.map((folder) => (
+                  <option key={folder.path} value={folder.path}>
+                    {folder.name}
+                  </option>
+                ))}
+              </FormSelect>
+            </FormField>
+            <Button type="submit">➕ Add Library</Button>
+          </FormRow>
+        </form>
+      </Card>
+
+      {/* Libraries Grid */}
+      <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-6">
+        {libraries.map((lib) => {
+          const seriesCount = seriesCountMap.get(lib.id) || 0;
+          return (
+            <Card key={lib.id} className="flex flex-col">
+              {/* Header with settings */}
+              <div className="flex items-start justify-between mb-3">
+                <div>
+                  <h3 className="text-lg font-semibold text-foreground">{lib.name}</h3>
+                  {!lib.enabled && <Badge variant="muted" className="mt-1">Disabled</Badge>}
+                </div>
+                <LibraryActions
+                  libraryId={lib.id}
+                  monitorEnabled={lib.monitor_enabled}
+                  scanMode={lib.scan_mode}
+                  watcherEnabled={lib.watcher_enabled}
+                />
+              </div>
+
+              {/* Path */}
+              <code className="text-xs font-mono text-muted mb-4 break-all">{lib.root_path}</code>
+
+              {/* Stats */}
+              <div className="grid grid-cols-2 gap-3 mb-4">
+                <Link href={`/libraries/${lib.id}/books`} className="text-center p-3 bg-muted/5 rounded-lg hover:bg-muted/10 transition-colors">
+                  <span className="block text-2xl font-bold text-primary">{lib.book_count}</span>
+                  <span className="text-xs text-muted">Books</span>
+                </Link>
+                <Link href={`/libraries/${lib.id}/series`} className="text-center p-3 bg-muted/5 rounded-lg hover:bg-muted/10 transition-colors">
+                  <span className="block text-2xl font-bold text-foreground">{seriesCount}</span>
+                  <span className="text-xs text-muted">Series</span>
+                </Link>
+              </div>
+
+              {/* Status */}
+              <div className="flex items-center gap-3 mb-4 text-sm">
+                <span className={`flex items-center gap-1 ${lib.monitor_enabled ? 'text-success' : 'text-muted'}`}>
+                  {lib.monitor_enabled ? '●' : '○'} {lib.monitor_enabled ? 'Auto' : 'Manual'}
+                </span>
+                {lib.watcher_enabled && (
+                  <span className="text-warning" title="File watcher active">⚡</span>
+                )}
+                {lib.monitor_enabled && lib.next_scan_at && (
+                  <span className="text-xs text-muted ml-auto">
+                    Next: {formatNextScan(lib.next_scan_at)}
+                  </span>
+                )}
+              </div>
+
+              {/* Actions */}
+              <div className="flex items-center gap-2 mt-auto">
+                <form className="flex-1">
+                  <input type="hidden" name="id" value={lib.id} />
+                  <Button type="submit" variant="primary" size="sm" className="w-full" formAction={scanLibraryAction}>
+                    🔄 Index
+                  </Button>
+                </form>
+                <form className="flex-1">
+                  <input type="hidden" name="id" value={lib.id} />
+                  <Button type="submit" variant="secondary" size="sm" className="w-full" formAction={scanLibraryFullAction}>
+                    🔁 Full
+                  </Button>
+                </form>
+                <form>
+                  <input type="hidden" name="id" value={lib.id} />
+                  <Button type="submit" variant="danger" size="sm" formAction={removeLibrary}>
+                    🗑
+                  </Button>
+                </form>
+              </div>
+            </Card>
+          );
+        })}
+      </div>
+    </>
+  );
+}