diff --git a/backend/alembic/versions/n7a8b9c0d142_collections.py b/backend/alembic/versions/n7a8b9c0d142_collections.py
new file mode 100644
index 0000000..b6a5bc6
--- /dev/null
+++ b/backend/alembic/versions/n7a8b9c0d142_collections.py
@@ -0,0 +1,33 @@
+"""Personal question libraries.
+
+Revision ID: n7a8b9c0d142
+Revises: m6a7b8c9d031
+"""
+from alembic import op
+
+revision = "n7a8b9c0d142"
+down_revision = "m6a7b8c9d031"
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.execute("""
+    CREATE TABLE IF NOT EXISTS user_collections (
+        id SERIAL PRIMARY KEY,
+        user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+        title VARCHAR(200) NOT NULL,
+        created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
+    )""")
+    op.execute("""
+    CREATE TABLE IF NOT EXISTS user_collection_questions (
+        id SERIAL PRIMARY KEY,
+        collection_id INTEGER NOT NULL REFERENCES user_collections(id) ON DELETE CASCADE,
+        question_id INTEGER NOT NULL REFERENCES questions(id) ON DELETE CASCADE,
+        CONSTRAINT uq_collection_question UNIQUE (collection_id, question_id)
+    )""")
+
+
+def downgrade():
+    op.execute("DROP TABLE IF EXISTS user_collection_questions")
+    op.execute("DROP TABLE IF EXISTS user_collections")
diff --git a/backend/app/main.py b/backend/app/main.py
index 6d00537..f423cf0 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -11,7 +11,7 @@ from app.logging_config import setup_logging
 setup_logging(settings.LOG_LEVEL)
 from app.database import engine, Base, SessionLocal
 from app.routers import auth, documents, quizzes, attempts, admin, tts, nextcloud, categories, questions, question_categories, favorites, teach, contact, tags, flashcards, courses, mobile, mynote
-from app.routers import study_tools, uploads, articles, comments, share
+from app.routers import study_tools, uploads, articles, comments, share, collections
 from app.utils.auth import get_password_hash
 from app.utils.scheduler import start_scheduler, stop_scheduler
 
@@ -619,6 +619,7 @@ app.include_router(auth.router, prefix="/api/auth", tags=["auth"])
 app.include_router(articles.router, prefix="/api/articles", tags=["articles"])
 app.include_router(comments.router, prefix="/api/comments", tags=["comments"])
 app.include_router(share.router, prefix="/api/share", tags=["share"])
+app.include_router(collections.router, prefix="/api/collections", tags=["collections"])
 app.include_router(documents.router, prefix="/api/documents", tags=["documents"])
 app.include_router(quizzes.router, prefix="/api/quizzes", tags=["quizzes"])
 app.include_router(attempts.router, prefix="/api/attempts", tags=["attempts"])
diff --git a/backend/app/models/__init__.py b/backend/app/models/__init__.py
index cba7335..4eba7fc 100644
--- a/backend/app/models/__init__.py
+++ b/backend/app/models/__init__.py
@@ -13,6 +13,7 @@ from app.models.article import Article, QuestionArticleLink
 from app.models.comment import Comment
 from app.models.flashcard import FlashcardDeck, Flashcard, FlashcardDeckRating, FlashcardQuestionLink, FlashcardArticleLink
 from app.models.question_category import QuestionCategory, QuestionCategoryLink
+from app.models.collection import UserCollection, UserCollectionQuestion
 
 __all__ = [
     "User",
@@ -38,4 +39,6 @@ __all__ = [
     "FlashcardArticleLink",
     "QuestionCategory",
     "QuestionCategoryLink",
+    "UserCollection",
+    "UserCollectionQuestion",
 ]
diff --git a/backend/app/models/collection.py b/backend/app/models/collection.py
new file mode 100644
index 0000000..c669ffd
--- /dev/null
+++ b/backend/app/models/collection.py
@@ -0,0 +1,22 @@
+from datetime import datetime
+
+from sqlalchemy import Column, DateTime, ForeignKey, Integer, String, UniqueConstraint
+from app.database import Base
+
+
+class UserCollection(Base):
+    __tablename__ = "user_collections"
+
+    id = Column(Integer, primary_key=True, index=True)
+    user_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False)
+    title = Column(String(200), nullable=False)
+    created_at = Column(DateTime, default=datetime.utcnow)
+
+
+class UserCollectionQuestion(Base):
+    __tablename__ = "user_collection_questions"
+    __table_args__ = (UniqueConstraint("collection_id", "question_id", name="uq_collection_question"),)
+
+    id = Column(Integer, primary_key=True, index=True)
+    collection_id = Column(Integer, ForeignKey("user_collections.id", ondelete="CASCADE"), nullable=False)
+    question_id = Column(Integer, ForeignKey("questions.id", ondelete="CASCADE"), nullable=False)
diff --git a/backend/app/routers/collections.py b/backend/app/routers/collections.py
new file mode 100644
index 0000000..83689d1
--- /dev/null
+++ b/backend/app/routers/collections.py
@@ -0,0 +1,100 @@
+"""Personal question libraries (saved questions)."""
+from fastapi import APIRouter, Depends, HTTPException
+from pydantic import BaseModel, field_validator
+from sqlalchemy.orm import Session
+
+from app.database import get_db
+from app.models.collection import UserCollection, UserCollectionQuestion
+from app.models.question import Question
+from app.models.user import User
+from app.services.quiz_builder import bank_question_predicate
+from app.utils.auth import get_current_user
+
+router = APIRouter()
+
+
+class CollectionCreate(BaseModel):
+    title: str
+
+    @field_validator("title")
+    @classmethod
+    def title_shape(cls, value):
+        value = value.strip()
+        if not value or len(value) > 200:
+            raise ValueError("Collection title is required (max 200 characters)")
+        return value
+
+
+class CollectionQuestionIn(BaseModel):
+    question_id: int
+
+
+def _own(db, user, collection_id):
+    collection = db.get(UserCollection, collection_id)
+    if not collection:
+        raise HTTPException(404, "Collection not found")
+    if collection.user_id != user.id:
+        raise HTTPException(403, "Not your collection")
+    return collection
+
+
+@router.get("/")
+def list_collections(db: Session = Depends(get_db), user: User = Depends(get_current_user)):
+    rows = db.query(UserCollection).filter(UserCollection.user_id == user.id).order_by(
+        UserCollection.created_at.desc()).all()
+    return [{"id": c.id, "title": c.title, "question_count": db.query(UserCollectionQuestion).filter(
+        UserCollectionQuestion.collection_id == c.id).count()} for c in rows]
+
+
+@router.post("/", status_code=201)
+def create_collection(data: CollectionCreate, db: Session = Depends(get_db), user: User = Depends(get_current_user)):
+    collection = UserCollection(user_id=user.id, title=data.title)
+    db.add(collection)
+    db.commit()
+    db.refresh(collection)
+    return {"id": collection.id, "title": collection.title, "question_count": 0}
+
+
+@router.patch("/{collection_id}")
+def rename_collection(collection_id: int, data: CollectionCreate, db: Session = Depends(get_db),
+                      user: User = Depends(get_current_user)):
+    collection = _own(db, user, collection_id)
+    collection.title = data.title
+    db.commit()
+    return {"id": collection.id, "title": collection.title}
+
+
+@router.delete("/{collection_id}", status_code=204)
+def delete_collection(collection_id: int, db: Session = Depends(get_db), user: User = Depends(get_current_user)):
+    db.delete(_own(db, user, collection_id))
+    db.commit()
+
+
+@router.get("/{collection_id}/questions")
+def collection_questions(collection_id: int, db: Session = Depends(get_db), user: User = Depends(get_current_user)):
+    collection = _own(db, user, collection_id)
+    rows = db.query(Question).join(UserCollectionQuestion, UserCollectionQuestion.question_id == Question.id).filter(
+        UserCollectionQuestion.collection_id == collection.id).all()
+    return [{"id": q.id, "question_text": q.question_text} for q in rows]
+
+
+@router.put("/{collection_id}/questions/{question_id}")
+def add_collection_question(collection_id: int, question_id: int, db: Session = Depends(get_db),
+                            user: User = Depends(get_current_user)):
+    collection = _own(db, user, collection_id)
+    if not db.query(Question.id).filter(Question.id == question_id, bank_question_predicate(user)).first():
+        raise HTTPException(404, "Question not found")
+    if db.query(UserCollectionQuestion.id).filter_by(collection_id=collection.id, question_id=question_id).first():
+        return {"added": False}
+    db.add(UserCollectionQuestion(collection_id=collection.id, question_id=question_id))
+    db.commit()
+    return {"added": True}
+
+
+@router.delete("/{collection_id}/questions/{question_id}", status_code=204)
+def remove_collection_question(collection_id: int, question_id: int, db: Session = Depends(get_db),
+                               user: User = Depends(get_current_user)):
+    _own(db, user, collection_id)
+    db.query(UserCollectionQuestion).filter_by(collection_id=collection_id, question_id=question_id).delete(
+        synchronize_session=False)
+    db.commit()
diff --git a/backend/app/routers/question_categories.py b/backend/app/routers/question_categories.py
index d8c59c4..e708304 100644
--- a/backend/app/routers/question_categories.py
+++ b/backend/app/routers/question_categories.py
@@ -1,7 +1,7 @@
 """Question category management; saved quiz membership is never changed here."""
 from fastapi import APIRouter, Depends, HTTPException
 from pydantic import BaseModel, Field
-from sqlalchemy import or_, select
+from sqlalchemy import or_, select, func
 from sqlalchemy.orm import Session
 
 from app.database import get_db
@@ -9,7 +9,7 @@ from app.models.question import Question
 from app.models.question_category import QuestionCategory, QuestionCategoryLink
 from app.models.user import User
 from app.services.quiz_builder import (bank_query, filtered_bank_query, category_descendants, category_breadcrumbs,
-    validate_parent, GenerateTestRequest, generate_test)
+    validate_parent, GenerateTestRequest, generate_test, bank_question_predicate)
 from app.utils.auth import get_current_user, require_moderator
 
 router = APIRouter()
@@ -32,21 +32,50 @@ class QCatResponse(BaseModel):
 
 def category_response(db, user, cat, cats):
     ids = category_descendants(cats, [cat.id])
-    extra = select(QuestionCategoryLink.question_id).where(QuestionCategoryLink.category_id.in_(ids))
-    count = bank_query(db, user).filter(or_(
-        Question.question_category_id.in_(ids),
-        Question.id.in_(extra),
-    )).count()
     return QCatResponse(id=cat.id, name=cat.name, description=cat.description, parent_id=cat.parent_id,
-        breadcrumbs=category_breadcrumbs(cats, cat.id),
-        question_count=count)
+        breadcrumbs=category_breadcrumbs(cats, cat.id), question_count=0)
+
+
+def _category_totals(db, user, by_id):
+    """Distinct question totals per category via ancestor set unions (fast, no N+1)."""
+    from collections import defaultdict
+    rows = bank_query(db, user).with_entities(Question.id, Question.question_category_id).all()
+    qids = [row[0] for row in rows]
+    direct = defaultdict(set)
+    for qid, cid in rows:
+        if cid is not None:
+            direct[cid].add(qid)
+    if qids:
+        for qid, cid in db.query(QuestionCategoryLink.question_id, QuestionCategoryLink.category_id).filter(
+                QuestionCategoryLink.question_id.in_(qids)).all():
+            direct[cid].add(qid)
+    ancestors = {}
+    for cat_id in by_id:
+        path, seen = [cat_id], set()
+        node = by_id[cat_id]
+        while node.parent_id and node.parent_id in by_id and node.parent_id not in seen:
+            seen.add(node.parent_id)
+            path.append(node.parent_id)
+            node = by_id[node.parent_id]
+        ancestors[cat_id] = path
+    totals = defaultdict(set)
+    for cid, question_set in direct.items():
+        for ancestor in ancestors.get(cid, [cid]):
+            totals[ancestor] |= question_set
+    return {cid: len(question_set) for cid, question_set in totals.items()}
 
 
 @router.get("/", response_model=list[QCatResponse])
 def list_question_categories(db: Session = Depends(get_db), current_user: User = Depends(get_current_user)):
     cats = db.query(QuestionCategory).order_by(QuestionCategory.name).all()
-    # ponytail: one count per category; aggregate counts if the taxonomy becomes large.
-    return [category_response(db, current_user, cat, cats) for cat in cats]
+    by_id = {cat.id: cat for cat in cats}
+    totals = _category_totals(db, current_user, by_id)
+    return [
+        QCatResponse(id=cat.id, name=cat.name, description=cat.description, parent_id=cat.parent_id,
+                     breadcrumbs=category_breadcrumbs(cats, cat.id),
+                     question_count=totals.get(cat.id, 0))
+        for cat in cats
+    ]
 
 
 def validate_category(db, data, cat_id=None):
diff --git a/backend/app/routers/questions.py b/backend/app/routers/questions.py
index 12cc6eb..bf94ec6 100644
--- a/backend/app/routers/questions.py
+++ b/backend/app/routers/questions.py
@@ -234,6 +234,8 @@ def get_question_bank(
     uncategorized: bool = Query(False),
     favorites_only: bool = Query(False),
     my_questions: bool = Query(False, description="Show only questions created by current user"),
+    difficulty: Literal["easy", "medium", "hard"] | None = Query(None),
+    article_ids: str | None = Query(None, description="Comma-separated article IDs (OR filter)"),
     tag_ids: str | None = Query(None, description="Comma-separated tag IDs (AND filter)"),
     search_mode: str = Query("hybrid"),  # "keyword" | "semantic" | "hybrid"
     limit: int = Query(50, le=200),
@@ -246,6 +248,15 @@ def get_question_bank(
     if my_questions:
         query = query.filter(Question.user_id == current_user.id)
 
+    if difficulty:
+        query = query.filter(Question.difficulty == difficulty)
+    if article_ids:
+        article_list = [int(part) for part in article_ids.split(",") if part.strip().isdigit()]
+        if article_list:
+            from app.models.article import QuestionArticleLink
+            query = query.filter(Question.id.in_(select(QuestionArticleLink.question_id).where(
+                QuestionArticleLink.article_id.in_(article_list))))
+
     if quiz_id:
         query = query.filter(Question.source_quiz_id == quiz_id)
 
@@ -504,10 +515,14 @@ def count_builder_questions(
     state: Literal["all", "unused", "incorrect", "bookmarked"] = "all",
     is_shared: bool = False,
     difficulty: Literal["easy", "medium", "hard"] | None = Query(None),
+    article_ids: str | None = Query(None, description="Comma-separated article IDs (OR filter)"),
+    tag_ids: str | None = Query(None, description="Comma-separated tag IDs (AND filter)"),
     db: Session = Depends(get_db),
     current_user: User = Depends(get_current_user),
 ):
-    return {"count": filtered_bank_query(db, current_user, category_ids, state, is_shared, difficulty).count()}
+    ids = [int(part) for part in (article_ids or "").split(",") if part.strip().isdigit()]
+    tag_list = [int(part) for part in (tag_ids or "").split(",") if part.strip().isdigit()]
+    return {"count": filtered_bank_query(db, current_user, category_ids, state, is_shared, difficulty, ids, tag_list).count()}
 
 
 @router.post("/builder")
diff --git a/backend/app/services/quiz_builder.py b/backend/app/services/quiz_builder.py
index 91d274f..1a292be 100644
--- a/backend/app/services/quiz_builder.py
+++ b/backend/app/services/quiz_builder.py
@@ -66,10 +66,27 @@ def bank_query(db, user):
     return db.query(Question).filter(bank_question_predicate(user))
 
 
-def filtered_bank_query(db, user, category_ids=(), state="all", shared=False, difficulty=None):
+def filtered_bank_query(db, user, category_ids=(), state="all", shared=False, difficulty=None, article_ids=(), tag_ids=()):
     query = bank_query(db, user)
     if difficulty:
         query = query.filter(Question.difficulty == difficulty)
+    if article_ids:
+        from app.models.article import QuestionArticleLink
+        query = query.filter(Question.id.in_(select(QuestionArticleLink.question_id).where(
+            QuestionArticleLink.article_id.in_(article_ids))))
+    if tag_ids:
+        from sqlalchemy import text as sa_text
+        tag_list = list(dict.fromkeys(tag_ids))
+        matching = list(db.execute(sa_text("""
+            SELECT question_id FROM question_tag_links
+            WHERE tag_id = ANY(:tag_ids)
+            GROUP BY question_id
+            HAVING COUNT(DISTINCT tag_id) = :cnt
+        """), {"tag_ids": tag_list, "cnt": len(tag_list)}).scalars())
+        if matching:
+            query = query.filter(Question.id.in_(matching))
+        else:
+            query = query.filter(Question.id.is_(None))  # No questions match all tags.
     if category_ids:
         ids = category_descendants(db.query(QuestionCategory).all(), category_ids)
         query = query.filter(or_(
@@ -127,6 +144,9 @@ class GenerateTestRequest(TestOptions):
     expected_count: int | None = Field(default=None, ge=0)
     difficulty: Literal["easy", "medium", "hard"] | None = None
     algorithm: Literal["random", "adaptive"] = "random"
+    article_ids: list[int] = Field(default_factory=list)
+    tag_ids: list[int] = Field(default_factory=list)
+    explicit_ids: list[int] = Field(default_factory=list)
 
 
 def create_saved_test(db, user, data, question_ids):
@@ -203,9 +223,9 @@ def generate_test(db, user, data):
         if len(ids) < data.count:
             raise HTTPException(400, f"Only {len(ids)} questions available; requested {data.count}")
         return create_saved_test(db, user, data, ids)
-    query = filtered_bank_query(db, user, data.category_ids, data.state, data.is_shared)
-    if data.difficulty:
-        query = query.filter(Question.difficulty == data.difficulty)
+    query = filtered_bank_query(db, user, data.category_ids, data.state, data.is_shared, data.difficulty, data.article_ids, data.tag_ids)
+    if data.explicit_ids:
+        query = query.filter(Question.id.in_(list(dict.fromkeys(data.explicit_ids))))
     ids = [row[0] for row in query.with_entities(Question.id).all()]
     if data.expected_count is not None and data.expected_count != len(ids):
         raise HTTPException(409, "Available count changed. Refresh the count and try again")
diff --git a/docs/quiz-revamp-plan.md b/docs/quiz-revamp-plan.md
index f4a36de..b47e250 100644
--- a/docs/quiz-revamp-plan.md
+++ b/docs/quiz-revamp-plan.md
@@ -70,3 +70,16 @@ Run frontend build and targeted/full relevant suites; obtain independent review,
 - Lab-reference support includes educator-managed entries and source/age/unit fields. Do not publish unsourced or AI-invented ranges. An honest empty state is permitted until verified clinical data is supplied.
 - The user has authorized implementation. Continue each completed milestone into verification, review, Git synchronization and the next milestone; stop only for a genuine blocker.
 - No migrations or deployments were performed during the initial scoping/Git synchronization. Subsequent implementation and validation evidence must be recorded in focused commits.
+
+## Pending backlog (2026-09-09)
+
+1. Category management page (with search): organize parents/subparents, create new parent, delete with move_to, move questions between categories; link from bank/create pages.
+2. Question editor: use shared CategoryTree facets (primary select + checkbox tree) — in progress.
+3. Create Custom Test facets: Status / Difficulty / Systems / Articles sections — code in progress; update tests (state is now buttons, not select).
+4. Upload flow: document → matched BANK questions via keywords/embeddings; min 10MB, max 30 questions, 5-day auto-delete.
+5. AI "describe what to study" → quiz from matched bank questions (all logged-in users).
+6. Quiz action buttons: analysis / rename / repeat / delete.
+7. Study recommendations from weakest categories.
+8. Dedicated question-management CMS page with per-category educator grants.
+9. Vision review finding: question-card row consistency (Study/Share alignment, answer-chip widths).
+10. Runner header spacing polish (question review / X of Y) — CSS added, verify visually.
diff --git a/frontend/src/components/CategoryPerformance.jsx b/frontend/src/components/CategoryPerformance.jsx
index 9a86436..1155320 100644
--- a/frontend/src/components/CategoryPerformance.jsx
+++ b/frontend/src/components/CategoryPerformance.jsx
@@ -1,9 +1,12 @@
 import { useEffect, useMemo, useState } from 'react'
+import { Link, useNavigate } from 'react-router-dom'
 import api from '../api/client'
 
 export default function CategoryPerformance() {
   const [data, setData] = useState(null)
   const [showAll, setShowAll] = useState(false)
+  const [adaptiveCount, setAdaptiveCount] = useState(10)
+  const navigate = useNavigate()
   useEffect(() => {
     api.get('/study-tools/performance-by-category')
       .then(res => setData(res.data))
@@ -42,19 +45,42 @@ export default function CategoryPerformance() {
       <div className="cp-heading">
         <h2 style={{ margin: 0 }}>Performance by category</h2>
         <button type="button" className="btn btn-secondary btn-sm" aria-expanded={showAll} onClick={() => setShowAll(v => !v)}>
-          {showAll ? 'Show main categories' : `Show all (${rows.length})`}
+          {showAll ? 'Close' : `Show all (${rows.length})`}
         </button>
       </div>
       <p style={{ color: 'var(--text-muted)', fontSize: '0.8rem', margin: '4px 0 12px' }}>{data.basis}</p>
-      {!showAll && main.map(renderRow)}
+      <div className="cp-adaptive-row">
+        <label className="cp-adaptive-label">Adaptive session
+          <select value={adaptiveCount} onChange={e => setAdaptiveCount(parseInt(e.target.value, 10))} aria-label="Adaptive question count">
+            {[3, 5, 10, 15, 20].map(n => <option key={n} value={n}>{n}</option>)}
+          </select>
+        </label>
+        <button type="button" className="btn btn-primary btn-sm"
+          onClick={() => navigate(`/quizzes/create?adaptive=1&count=${adaptiveCount}`)}>Start adaptive session</button>
+        {main.length > 0 && (
+          <button type="button" className="btn btn-secondary btn-sm"
+            onClick={() => navigate(`/quizzes/create?adaptive=1&count=${adaptiveCount}&${main.slice(0, 3).map(row => `category=${row.category_id}`).join('&')}`)}>
+            On my weakest topics
+          </button>
+        )}
+      </div>
+      {main.map(renderRow)}
       {showAll && (
-        <div className="cp-all">
-          {main.map(row => (
-            <div key={row.category_id}>
-              {renderRow(row)}
-              {renderBranch(row.category_id, 1)}
+        <div className="cp-overlay" role="dialog" aria-label="All category performance">
+          <div className="cp-panel">
+            <header className="cp-panel-header">
+              <h2>All categories</h2>
+              <button type="button" aria-label="Close all categories" onClick={() => setShowAll(false)}>✕</button>
+            </header>
+            <div className="cp-panel-body">
+              {main.map(row => (
+                <div key={row.category_id}>
+                  {renderRow(row)}
+                  {renderBranch(row.category_id, 1)}
+                </div>
+              ))}
             </div>
-          ))}
+          </div>
         </div>
       )}
     </div>
diff --git a/frontend/src/components/CategoryPerformance.test.jsx b/frontend/src/components/CategoryPerformance.test.jsx
index af661b7..a16f0ae 100644
--- a/frontend/src/components/CategoryPerformance.test.jsx
+++ b/frontend/src/components/CategoryPerformance.test.jsx
@@ -1,5 +1,7 @@
 import { beforeEach, describe, expect, it, vi } from 'vitest'
-import { render, screen, waitFor } from '@testing-library/react'
+import { render, screen, waitFor, within } from '@testing-library/react'
+import userEvent from '@testing-library/user-event'
+import { MemoryRouter } from 'react-router-dom'
 import CategoryPerformance from './CategoryPerformance'
 import api from '../api/client'
 
@@ -13,22 +15,30 @@ describe('category performance', () => {
       total_answered: 3,
       basis: 'Your completed, non-expired general test answers.',
       categories: [
-        { category_id: 2, name: 'Clinical reasoning', answered: 2, correct: 1, accuracy: 50 },
-        { category_id: 1, name: 'Pediatrics', answered: 1, correct: 1, accuracy: 100 },
+        { category_id: 2, name: 'Clinical reasoning', parent_id: null, answered: 2, correct: 1, accuracy: 50 },
+        { category_id: 1, name: 'Pediatrics', parent_id: null, answered: 1, correct: 1, accuracy: 100 },
+        { category_id: 3, name: 'Neonatal', parent_id: 1, answered: 1, correct: 0, accuracy: 0 },
       ],
     } })
-    render(<CategoryPerformance />)
+    render(<MemoryRouter><CategoryPerformance /></MemoryRouter>)
     expect(await screen.findByTestId('category-performance')).toBeInTheDocument()
     expect(screen.getByText('Clinical reasoning')).toBeInTheDocument()
     expect(screen.getByText('50%')).toBeInTheDocument()
     expect(screen.getByText('1/2')).toBeInTheDocument()
     expect(screen.getByText('100%')).toBeInTheDocument()
     expect(screen.getByText(/completed, non-expired/)).toBeInTheDocument()
+    // Child rows stay out of the compact view until the side panel opens.
+    expect(screen.queryByText('Neonatal')).not.toBeInTheDocument()
+    await userEvent.click(screen.getByRole('button', { name: 'Show all (3)' }))
+    const panel = await screen.findByRole('dialog', { name: 'All category performance' })
+    expect(within(panel).getByText('Neonatal')).toBeInTheDocument()
+    await userEvent.click(within(panel).getByRole('button', { name: 'Close all categories' }))
+    expect(screen.queryByRole('dialog')).not.toBeInTheDocument()
   })
 
   it('renders nothing without category data', async () => {
     api.get.mockResolvedValue({ data: { total_answered: 0, categories: [] } })
-    const { container } = render(<CategoryPerformance />)
+    const { container } = render(<MemoryRouter><CategoryPerformance /></MemoryRouter>)
     await waitFor(() => expect(api.get).toHaveBeenCalled())
     await new Promise(resolve => setTimeout(resolve, 0))
     expect(container.querySelector('[data-testid="category-performance"]')).toBeNull()
diff --git a/frontend/src/components/CategoryTree.jsx b/frontend/src/components/CategoryTree.jsx
new file mode 100644
index 0000000..9385270
--- /dev/null
+++ b/frontend/src/components/CategoryTree.jsx
@@ -0,0 +1,55 @@
+import { useState } from 'react'
+
+export default function CategoryTree({ categories, selectedIds, onToggle, excludedId = null, searchable = false }) {
+  const [query, setQuery] = useState('')
+  const childrenOf = {}
+  for (const cat of categories) {
+    ;(childrenOf[cat.parent_id || 0] ||= []).push(cat)
+  }
+  const visible = searchable
+    ? categories.filter(cat => [cat.name, ...(cat.breadcrumbs || []).map(b => b.name)].join(' ').toLowerCase().includes(query.toLowerCase()))
+    : categories
+  const descendantSelected = (cat) => {
+    const ids = []
+    const walk = (id) => { for (const child of childrenOf[id] || []) { ids.push(child.id); walk(child.id) } }
+    walk(cat.id)
+    return ids.some(id => selectedIds.includes(id))
+  }
+  const renderBranch = (parentId) => {
+    const branch = (childrenOf[parentId] || []).filter(cat => visible.includes(cat))
+    if (!branch.length) return null
+    return <ul className="category-tree">
+      {branch.map(cat => {
+        const excluded = cat.id === excludedId
+        const node = (
+          <label className={excluded ? 'category-tree-excluded' : ''}>
+            <input type="checkbox" checked={selectedIds.includes(cat.id)} disabled={excluded}
+              onChange={e => onToggle(cat.id, e.target.checked)} />
+            <span className="category-tree-name">{cat.name}</span>
+            <span className="category-tree-count">({cat.question_count})</span>
+          </label>
+        )
+        const kids = (childrenOf[cat.id] || []).filter(child => visible.includes(child))
+        if (!kids.length) return <li key={cat.id}>{node}</li>
+        return <li key={cat.id}>
+          <details open={!!query || selectedIds.includes(cat.id) || descendantSelected(cat)}>
+            <summary className="category-tree-branch"><span className="category-tree-chevron" aria-hidden="true" />{node}</summary>
+            {renderBranch(cat.id)}
+          </details>
+        </li>
+      })}
+    </ul>
+  }
+  return (
+    <div className="category-tree-wrap">
+      {searchable && (
+        <div className="custom-test-search">
+          <span className="custom-test-search-icon" aria-hidden="true">🔍</span>
+          <input type="search" value={query} onChange={e => setQuery(e.target.value)}
+            placeholder="Search topics…" aria-label="Search topics" className="input" />
+        </div>
+      )}
+      {renderBranch(0)}
+    </div>
+  )
+}
diff --git a/frontend/src/components/CommentSection.jsx b/frontend/src/components/CommentSection.jsx
index 7e94f69..2143cb8 100644
--- a/frontend/src/components/CommentSection.jsx
+++ b/frontend/src/components/CommentSection.jsx
@@ -18,7 +18,7 @@ export default function CommentSection({ articleId, questionId }) {
 
   const load = useCallback(async (off = 0) => {
     try {
-      const res = await api.get('/comments', { params: { ...params, limit: LIMIT, offset: off } })
+      const res = await api.get('/comments/', { params: { ...params, limit: LIMIT, offset: off } })
       const list = res.data?.comments || []
       setComments(prev => off === 0 ? list : [...prev, ...list])
       setTotal(res.data?.total || 0)
@@ -33,7 +33,7 @@ export default function CommentSection({ articleId, questionId }) {
     setError('')
     setSubmitting(true)
     try {
-      const res = await api.post('/comments', { ...params, content: draft })
+      const res = await api.post('/comments/', { ...params, content: draft })
       setComments(prev => [res.data, ...prev.filter(c => c.id !== res.data.id)])
       setTotal(t => t + 1)
       setDraft('')
diff --git a/frontend/src/components/CommentSection.test.jsx b/frontend/src/components/CommentSection.test.jsx
index 7524024..ee544d7 100644
--- a/frontend/src/components/CommentSection.test.jsx
+++ b/frontend/src/components/CommentSection.test.jsx
@@ -31,7 +31,7 @@ describe('comment section', () => {
     await screen.findByRole('heading', { name: /Discussion/ })
     await userEvent.type(screen.getByLabelText('Comment text'), 'New note')
     await userEvent.click(screen.getByRole('button', { name: 'Post comment' }))
-    await waitFor(() => expect(api.post).toHaveBeenCalledWith('/comments', { question_id: 5, content: 'New note' }))
+    await waitFor(() => expect(api.post).toHaveBeenCalledWith('/comments/', { question_id: 5, content: 'New note' }))
     expect(await screen.findByText('New note')).toBeInTheDocument()
   })
 
diff --git a/frontend/src/index.css b/frontend/src/index.css
index b33406e..4693e49 100644
--- a/frontend/src/index.css
+++ b/frontend/src/index.css
@@ -746,3 +746,17 @@ body {
   .category-performance-row { grid-template-columns: 1fr 56px; }
   .cp-track { grid-column: 1 / -1; grid-row: 2; }
 }
+.cp-heading { display: flex; justify-content: space-between; align-items: center; gap: 10px; flex-wrap: wrap; }
+.cp-overlay { position: fixed; inset: 0; background: rgba(15, 23, 42, 0.35); z-index: 1050; display: flex; justify-content: flex-end; }
+.cp-panel { background: var(--card-bg); width: min(520px, 92vw); height: 100%; display: flex; flex-direction: column; box-shadow: -12px 0 40px rgba(0,0,0,0.18); }
+.cp-panel-header { display: flex; justify-content: space-between; align-items: center; padding: 14px 18px; border-bottom: 1px solid var(--border); }
+.cp-panel-header h2 { margin: 0; font-size: 1rem; }
+.cp-panel-header button { background: none; border: none; font-size: 1.1rem; cursor: pointer; color: var(--text-muted); }
+.cp-panel-body { flex: 1; overflow-y: auto; padding: 14px 18px; }
+@media (max-width: 640px) {
+  .cp-overlay { align-items: flex-end; }
+  .cp-panel { width: 100%; height: 85vh; border-radius: 16px 16px 0 0; }
+}
+.cp-adaptive-row { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; margin-bottom: 12px; padding: 10px; border: 1px solid var(--border); border-radius: 10px; background: var(--input-bg); }
+.cp-adaptive-label { display: flex; align-items: center; gap: 6px; font-size: .82rem; }
+.cp-adaptive-label select { padding: 4px 8px; border: 1px solid var(--border); border-radius: 6px; }
diff --git a/frontend/src/pages/ArticlesPage.jsx b/frontend/src/pages/ArticlesPage.jsx
index d99b22f..1575e63 100644
--- a/frontend/src/pages/ArticlesPage.jsx
+++ b/frontend/src/pages/ArticlesPage.jsx
@@ -49,7 +49,7 @@ export default function ArticlesPage() {
     const params = {}
     if (categoryId) params.category_id = categoryId
     if (query.trim()) params.q = query.trim()
-    api.get('/articles', { params }).then(res => setArticles(res.data)).finally(() => setLoading(false))
+    api.get('/articles/', { params }).then(res => setArticles(res.data)).finally(() => setLoading(false))
   }, [categoryId, query])
 
   useEffect(() => { load() }, [load])
@@ -61,7 +61,7 @@ export default function ArticlesPage() {
     setError('')
     if (!title.trim() || !slug.trim()) { setError('Title and slug are required'); return }
     try {
-      const res = await api.post('/articles', { title, slug: slug.trim().toLowerCase(), content: '', sections: [] })
+      const res = await api.post('/articles/', { title, slug: slug.trim().toLowerCase(), content: '', sections: [] })
       setShowCreate(false)
       navigate(`/articles/${res.data.id}?edit=1`)
     } catch (err) {
diff --git a/frontend/src/pages/ArticlesPage.test.jsx b/frontend/src/pages/ArticlesPage.test.jsx
index f14bdc3..be6a42f 100644
--- a/frontend/src/pages/ArticlesPage.test.jsx
+++ b/frontend/src/pages/ArticlesPage.test.jsx
@@ -22,7 +22,7 @@ beforeEach(() => {
   vi.resetAllMocks()
   api.get.mockImplementation(url => {
     if (url === '/question-categories') return Promise.resolve({ data: [] })
-    if (url === '/articles') return Promise.resolve({ data: [article] })
+    if (url === '/articles/') return Promise.resolve({ data: [article] })
     if (url === '/articles/linked') return Promise.resolve({ data: [article] })
     if (url === '/articles/1') return Promise.resolve({ data: article })
     if (url === '/articles/1/questions') return Promise.resolve({ data: [{ question_id: 1, question_text: 'Linked question text', correct_answer: 'yes', explanation: 'Why', section_id: null }] })
diff --git a/frontend/src/pages/CustomQuizPage.css b/frontend/src/pages/CustomQuizPage.css
index 22b40e1..34f23af 100644
--- a/frontend/src/pages/CustomQuizPage.css
+++ b/frontend/src/pages/CustomQuizPage.css
@@ -52,3 +52,6 @@ details[open] > .custom-test-branch .custom-test-chevron { transform: rotate(45d
 .custom-test-actions .btn-primary { flex: 1; background: var(--primary); color: var(--primary-fg); font-weight: 600; padding: 10px 16px; }
 .custom-test-main > p { margin: 8px 0 0; }
 .custom-test-main > .custom-test-share { margin-top: 8px; }
+.custom-test-tags { display: flex; flex-direction: column; gap: 2px; max-height: 24vh; overflow-y: auto; }
+.custom-test-tags label { display: flex; gap: 6px; align-items: baseline; font-size: .82rem; cursor: pointer; }
+.custom-test-exam { display: flex; gap: 6px; align-items: center; font-size: .84rem; font-weight: 600; color: var(--primary); margin: 4px 0; }
diff --git a/frontend/src/pages/CustomQuizPage.jsx b/frontend/src/pages/CustomQuizPage.jsx
index 3cd2669..f62a660 100644
--- a/frontend/src/pages/CustomQuizPage.jsx
+++ b/frontend/src/pages/CustomQuizPage.jsx
@@ -12,12 +12,18 @@ export default function CustomQuizPage() {
   const [categoryIds, setCategoryIds] = useState(() => [...new Set(searchParams.getAll('category').map(Number).filter(id => Number.isSafeInteger(id) && id > 0))])
   const [state, setState] = useState('all')
   const [shared, setShared] = useState(false)
-  const [title, setTitle] = useState(() => `Custom test from ${new Date().toLocaleDateString('en-US', { month: 'short', day: 'numeric' })}`)
+  const [title, setTitle] = useState(() => {
+    const now = new Date()
+    return `Custom test from ${now.toLocaleDateString('en-US', { month: 'short', day: 'numeric' })}, ${now.toLocaleTimeString('en-US', { hour: 'numeric', hour12: true })}`
+  })
   const [mode, setMode] = useState('learning')
   const [time, setTime] = useState('')
-  const [count, setCount] = useState(20)
+  const [count, setCount] = useState(() => {
+    const fromUrl = parseInt(searchParams.get('count'), 10)
+    return Number.isInteger(fromUrl) && fromUrl >= 1 && fromUrl <= 200 ? fromUrl : 20
+  })
   const [difficulty, setDifficulty] = useState('')
-  const [adaptive, setAdaptive] = useState(false)
+  const [adaptive, setAdaptive] = useState(() => searchParams.get('adaptive') === '1')
   const [available, setAvailable] = useState(null)
   const [countKey, setCountKey] = useState(null)
   const [error, setError] = useState('')
@@ -40,6 +46,8 @@ export default function CustomQuizPage() {
     const params = new URLSearchParams({ state, is_shared: String(shared) })
     if (difficulty) params.append('difficulty', difficulty)
     categoryIds.forEach(id => params.append('category_ids', id))
+    articleIds.forEach(id => params.append('article_ids', id))
+    tagIds.forEach(id => params.append('tag_ids', id))
     api.get('/questions/builder/count', { params }).then(r => {
       if (active) { setAvailable(r.data.count); setCountKey(filterKey) }
     }).catch(() => { if (active) setCountError('Could not load available count. Try refreshing.') })
@@ -58,6 +66,7 @@ export default function CustomQuizPage() {
         title: title.trim(), category_ids: categoryIds, state, count: Number(count),
         expected_count: available, mode, time_limit_minutes: mode === 'timed' && time ? Number(time) : null,
         is_shared: shared, difficulty: difficulty || null, algorithm: adaptive ? 'adaptive' : 'random',
+        article_ids: articleIds, tag_ids: tagIds, explicit_ids: explicitIds,
       })
       navigate(`/quizzes/${result.data.id}`)
     } catch (err) {
@@ -69,6 +78,26 @@ export default function CustomQuizPage() {
 
   const [catSearch, setCatSearch] = useState('')
   const [filtersOpen, setFiltersOpen] = useState(true)
+  const [articleIds, setArticleIds] = useState([])
+  const [tagIds, setTagIds] = useState([])
+  const [articles, setArticles] = useState([])
+  const [tags, setTags] = useState({ subjects: [], keywords: [] })
+  const [presetIds, setPresetIds] = useState([])
+  const [collections, setCollections] = useState([])
+  useEffect(() => {
+    api.get('/articles/').then(res => setArticles(Array.isArray(res.data) ? res.data : [])).catch(() => setArticles([]))
+    api.get('/tags').then(res => setTags(res.data && res.data.subjects ? res.data : { subjects: [], keywords: [] })).catch(() => {})
+    api.get('/collections/').then(res => setCollections(Array.isArray(res.data) ? res.data : [])).catch(() => setCollections([]))
+  }, [])
+  const togglePreset = async (collection) => {
+    if (presetIds.includes(collection.id)) { setPresetIds(ids => ids.filter(id => id !== collection.id)); return }
+    setPresetIds(ids => [...ids, collection.id])
+    if (!collection._loaded) {
+      const res = await api.get(`/collections/${collection.id}/questions`)
+      setCollections(prev => prev.map(c => c.id === collection.id ? { ...c, _loaded: true, question_ids: res.data.map(q => q.id) } : c))
+    }
+  }
+  const explicitIds = [...new Set(collections.filter(c => presetIds.includes(c.id)).flatMap(c => c.question_ids || []))]
   const childrenOf = {}
   for (const cat of categories) {
     ;(childrenOf[cat.parent_id || 0] ||= []).push(cat)
@@ -114,7 +143,42 @@ export default function CustomQuizPage() {
           <button type="button" className="custom-test-filters-toggle" aria-expanded={filtersOpen}
             onClick={() => setFiltersOpen(v => !v)}>{filtersOpen ? '✕ Hide filters' : '☰ Filters'}</button>
           <div className={`custom-test-filters-body ${filtersOpen ? 'open' : ''}`}>
-            <h2>Topics</h2>
+            <h2>Filters</h2>
+            <h3>Status</h3>
+            <div className="bank-state-buttons">
+              {[['all', 'All'], ['unused', 'Unused'], ['incorrect', 'Incorrect'], ['bookmarked', 'Saved']].map(([value, label]) => (
+                <button key={value} type="button" className={`btn btn-sm ${state === value ? 'btn-primary' : 'btn-secondary'}`}
+                  onClick={() => setState(value)}>{label}</button>
+              ))}
+            </div>
+            <h3>Difficulty</h3>
+            <select value={difficulty} onChange={e => setDifficulty(e.target.value)} className="input" aria-label="Difficulty">
+              <option value="">Any</option><option value="easy">Easy</option>
+              <option value="medium">Medium</option><option value="hard">Hard</option>
+            </select>
+            <h3>Exams</h3>
+            <label className="custom-test-exam"><input type="checkbox" checked readOnly /> Pediatrics Boards</label>
+            <h3>Disciplines</h3>
+            <div className="custom-test-tags">
+              {(tags.subjects || []).slice(0, 40).map(tag => (
+                <label key={tag.id}>
+                  <input type="checkbox" checked={tagIds.includes(tag.id)}
+                    onChange={e => setTagIds(ids => e.target.checked ? [...ids, tag.id] : ids.filter(id => id !== tag.id))} />
+                  {tag.name}
+                </label>
+              ))}
+            </div>
+            <h3>Symptoms & keywords</h3>
+            <div className="custom-test-tags">
+              {(tags.keywords || []).slice(0, 40).map(tag => (
+                <label key={tag.id}>
+                  <input type="checkbox" checked={tagIds.includes(tag.id)}
+                    onChange={e => setTagIds(ids => e.target.checked ? [...ids, tag.id] : ids.filter(id => id !== tag.id))} />
+                  {tag.name}
+                </label>
+              ))}
+            </div>
+            <h3>Systems</h3>
             <p>Parent categories include all their subcategories.</p>
             <div className="custom-test-search">
               <span className="custom-test-search-icon" aria-hidden="true">🔍</span>
@@ -123,19 +187,32 @@ export default function CustomQuizPage() {
             </div>
             {renderTree(0)}
             <button type="button" className="btn btn-secondary btn-sm" onClick={() => setCategoryIds([])}>Clear categories</button>
+            <h3>Saved</h3>
+            <div className="custom-test-tags">
+              <label><input type="checkbox" checked={state === 'bookmarked'} onChange={e => setState(e.target.checked ? 'bookmarked' : 'all')} /> Bookmarked questions</label>
+              {collections.map(collection => (
+                <label key={collection.id}>
+                  <input type="checkbox" checked={presetIds.includes(collection.id)} onChange={() => togglePreset(collection)} />
+                  {collection.title} ({collection.question_count})
+                </label>
+              ))}
+            </div>
+            <h3>Articles</h3>
+            <div className="custom-test-articles">
+              {(articles || []).map(article => (
+                <label key={article.id}>
+                  <input type="checkbox" checked={articleIds.includes(article.id)}
+                    onChange={e => setArticleIds(ids => e.target.checked ? [...ids, article.id] : ids.filter(id => id !== article.id))} />
+                  {article.title}
+                </label>
+              ))}
+              {(articles || []).length === 0 && <p style={{ color: 'var(--text-muted)', fontSize: '.8rem' }}>No articles yet.</p>}
+            </div>
           </div>
         </aside>
         <div className="custom-test-main">
           <div className="custom-test-settings card">
             <label>Title<input required maxLength={200} value={title} onChange={e => setTitle(e.target.value)} className="custom-test-title-input" /></label>
-            <label>Question state<select value={state} onChange={e => setState(e.target.value)}>
-              <option value="all">All</option><option value="unused">Unused</option>
-              <option value="incorrect">Incorrect</option><option value="bookmarked">Bookmarked</option>
-            </select></label>
-            <label>Difficulty<select value={difficulty} onChange={e => setDifficulty(e.target.value)}>
-              <option value="">Any</option><option value="easy">Easy</option>
-              <option value="medium">Medium</option><option value="hard">Hard</option>
-            </select></label>
             <label className="custom-test-adaptive"><input type="checkbox" checked={adaptive} onChange={e => setAdaptive(e.target.checked)} /> <span className="custom-test-switch" aria-hidden="true"><span /></span> Adaptive session</label>
             {adaptive && <p className="custom-test-adaptive-note">Adaptive picks your weakest topics first: it prefers unanswered questions, then recycles older incorrect ones, and moves between weak areas instead of repeating one.</p>}
             <label>Number of questions<input type="number" required min="1" max="200" step="1" value={count} onChange={e => setCount(e.target.value)} /></label>
diff --git a/frontend/src/pages/CustomQuizPage.test.jsx b/frontend/src/pages/CustomQuizPage.test.jsx
index d3ebcd1..8f54a8c 100644
--- a/frontend/src/pages/CustomQuizPage.test.jsx
+++ b/frontend/src/pages/CustomQuizPage.test.jsx
@@ -13,7 +13,11 @@ const categories = [
   { id: 2, name: 'Neonatal', question_count: 10, breadcrumbs: [{ id: 1, name: 'Pediatrics' }, { id: 2, name: 'Neonatal' }] },
 ]
 function setupCount(count = 30) {
-  api.get.mockImplementation(url => Promise.resolve({ data: url === '/question-categories/' ? categories : { count } }))
+  api.get.mockImplementation(url => {
+    if (url === '/question-categories/') return Promise.resolve({ data: categories })
+    if (url.startsWith('/articles') || url.startsWith('/collections') || url.startsWith('/tags')) return Promise.resolve({ data: url.startsWith('/articles') ? [] : url.startsWith('/collections') ? [] : { subjects: [], keywords: [] } })
+    return Promise.resolve({ data: { count } })
+  })
 }
 function renderBuilder() {
   render(<MemoryRouter initialEntries={['/quizzes/create']}><Routes>
@@ -34,7 +38,7 @@ describe('CustomQuizPage', () => {
     expect(screen.queryByLabelText(/Time limit/)).not.toBeInTheDocument()
     await userEvent.click(screen.getByLabelText('Pediatrics (30)'))
     await userEvent.click(screen.getByLabelText('Neonatal (10)'))
-    await userEvent.selectOptions(screen.getByLabelText('Question state'), 'incorrect')
+    await userEvent.click(screen.getByRole('button', { name: 'Unused' }))
     await userEvent.selectOptions(screen.getByLabelText('Mode'), 'timed')
     fireEvent.change(screen.getByLabelText(/Time limit/), { target: { value: '15' } })
     fireEvent.change(screen.getByLabelText('Number of questions'), { target: { value: '10' } })
@@ -43,13 +47,13 @@ describe('CustomQuizPage', () => {
     const calls = api.get.mock.calls.filter(([url]) => url === '/questions/builder/count')
     const params = calls.at(-1)[1].params
     expect(params.getAll('category_ids')).toEqual(['1', '2'])
-    expect(params.get('state')).toBe('incorrect')
+    expect(params.get('state')).toBe('unused')
     expect(params.get('is_shared')).toBe('true')
     await userEvent.click(screen.getByRole('button', { name: 'Create Test' }))
     expect(api.post).toHaveBeenCalledWith('/questions/builder', {
-      title: `Custom test from ${new Date().toLocaleDateString('en-US', { month: 'short', day: 'numeric' })}`, category_ids: [1, 2], state: 'incorrect', count: 10,
+      title: `Custom test from ${new Date().toLocaleDateString('en-US', { month: 'short', day: 'numeric' })}, ${new Date().toLocaleTimeString('en-US', { hour: 'numeric', hour12: true })}`, category_ids: [1, 2], state: 'unused', count: 10,
       mode: 'timed', time_limit_minutes: 15, expected_count: 30, is_shared: true,
-      difficulty: null, algorithm: 'random',
+      difficulty: null, algorithm: 'random', article_ids: [], tag_ids: [], explicit_ids: [],
     })
     await screen.findByRole('heading', { name: 'Saved test' })
   })
@@ -92,7 +96,7 @@ describe('CustomQuizPage', () => {
     await screen.findByLabelText('Pediatrics (30)')
     const old = resolveOld
     setupCount(4)
-    await userEvent.selectOptions(screen.getByLabelText('Question state'), 'bookmarked')
+    await userEvent.click(screen.getByRole('button', { name: 'Saved' }))
     await screen.findByText('4 questions available')
     old({ data: { count: 100 } })
     await waitFor(() => expect(screen.queryByText('100 questions available')).not.toBeInTheDocument())
diff --git a/frontend/src/pages/QuestionBankPage.css b/frontend/src/pages/QuestionBankPage.css
index df82ed9..dfea4ee 100644
--- a/frontend/src/pages/QuestionBankPage.css
+++ b/frontend/src/pages/QuestionBankPage.css
@@ -21,3 +21,16 @@
   .bank-layout { grid-template-columns: 1fr; }
   .bank-category-list { max-height: none; }
 }
+.category-tree-wrap { margin-top: 6px; }
+.category-tree { list-style: none; margin: 0; padding: 0; max-height: 46vh; overflow-y: auto; }
+.category-tree ul { list-style: none; margin: 0 0 0 16px; padding: 0; }
+.category-tree li { margin: 1px 0; }
+.category-tree label { display: flex; align-items: baseline; gap: 6px; font-size: .84rem; cursor: pointer; }
+.category-tree-count { color: var(--text-muted); font-size: .74rem; }
+.category-tree-excluded { opacity: .5; }
+.category-tree-branch { display: flex; align-items: center; cursor: pointer; list-style: none; }
+.category-tree-branch::-webkit-details-marker { display: none; }
+.category-tree-chevron { display: inline-block; width: 7px; height: 7px; border-right: 2px solid var(--text-muted); border-bottom: 2px solid var(--text-muted); transform: rotate(-45deg); margin-right: 6px; transition: transform .15s ease; flex-shrink: 0; }
+details[open] > .category-tree-branch .category-tree-chevron { transform: rotate(45deg); }
+.bank-articles { display: flex; flex-direction: column; gap: 3px; margin-top: 6px; max-height: 30vh; overflow-y: auto; }
+.bank-articles label { display: flex; gap: 6px; align-items: baseline; font-size: .82rem; cursor: pointer; }
diff --git a/frontend/src/pages/QuestionBankPage.jsx b/frontend/src/pages/QuestionBankPage.jsx
index 5fa7551..404b73d 100644
--- a/frontend/src/pages/QuestionBankPage.jsx
+++ b/frontend/src/pages/QuestionBankPage.jsx
@@ -3,6 +3,7 @@ import { useNavigate, Link } from 'react-router-dom'
 import { useAuth } from '../context/AuthContext'
 import api from '../api/client'
 import Dialog from '../components/Dialog'
+import CategoryTree from '../components/CategoryTree'
 import { useDialog } from '../hooks/useDialog'
 
 const TeachChat = lazy(() => import('../components/TeachChat'))
@@ -22,7 +23,7 @@ function stripHtml(html) {
   return html.replace(/<[^>]+>/g, ' ').replace(/&nbsp;/g, ' ').replace(/&amp;/g, '&').replace(/&lt;/g, '<').replace(/&gt;/g, '>').replace(/\s+/g, ' ').trim()
 }
 
-function QuestionStudyModal({ question, onClose, isFavorited, onToggleFavorite }) {
+function QuestionStudyModal({ question, onClose, isFavorited, onToggleFavorite, collections = [] }) {
   const [answered, setAnswered] = useState(null)
   return (
     <>
@@ -105,6 +106,27 @@ function QuestionStudyModal({ question, onClose, isFavorited, onToggleFavorite }
             </div>
           )}
           <QuestionReadingLinks questionId={question.id} />
+          <div style={{ marginTop: 12, borderTop: '1px solid var(--border)', paddingTop: 10, fontSize: '0.85rem' }}>
+            <strong>Add to library</strong>
+            <div style={{ display: 'flex', gap: 8, marginTop: 6, flexWrap: 'wrap' }}>
+              <select defaultValue="" onChange={async e => {
+                if (!e.target.value) return
+                await api.put(`/collections/${e.target.value}/questions/${question.id}`)
+                e.target.value = ''
+              }} aria-label="Add to collection">
+                <option value="">Choose collection…</option>
+                {collections.map(c => <option key={c.id} value={c.id}>{c.title}</option>)}
+              </select>
+              <input placeholder="New library…" aria-label="New library name" onKeyDown={async e => {
+                if (e.key === 'Enter' && e.target.value.trim()) {
+                  const res = await api.post('/collections/', { title: e.target.value.trim() })
+                  await api.put(`/collections/${res.data.id}/questions/${question.id}`)
+                  setCollections(prev => [...prev, res.data])
+                  e.target.value = ''
+                }
+              }} style={{ padding: '4px 10px', border: '1px solid var(--border)', borderRadius: 6, fontSize: '0.8rem' }} />
+            </div>
+          </div>
           {answered && (
             <div style={{ marginTop: 14, display: 'flex', gap: 8 }}>
               <button className="btn btn-secondary btn-sm" onClick={() => setAnswered(null)}>Try again</button>
@@ -323,7 +345,7 @@ function QuestionEditModal({ question, categories, onSaved, onClose }) {
   return (
     <div style={{ position: 'fixed', inset: 0, background: 'rgba(0,0,0,0.55)', zIndex: 1000, display: 'flex', alignItems: 'center', justifyContent: 'center', padding: 16 }}
       onClick={e => e.target === e.currentTarget && onClose()}>
-      <div style={{ background: 'var(--card-bg)', borderRadius: 12, padding: 24, maxWidth: 640, width: '100%', maxHeight: '90vh', overflowY: 'auto', boxShadow: '0 20px 60px rgba(0,0,0,0.3)' }}>
+      <div role="dialog" aria-label="Edit Question" style={{ background: 'var(--card-bg)', borderRadius: 12, padding: 24, maxWidth: 640, width: '100%', maxHeight: '90vh', overflowY: 'auto', boxShadow: '0 20px 60px rgba(0,0,0,0.3)' }}>
         <div style={{ display: 'flex', justifyContent: 'space-between', marginBottom: 16 }}>
           <h2 style={{ fontSize: '1.1rem' }}>Edit Question</h2>
           <button onClick={onClose} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-muted)', fontSize: '1.2rem' }}>✕</button>
@@ -368,28 +390,20 @@ function QuestionEditModal({ question, categories, onSaved, onClose }) {
           </div>
         )}
         <div className="form-group">
-          <label>Question Category</label>
-          <select value={form.question_category_id} onChange={e => setForm(f => ({ ...f, question_category_id: e.target.value }))}>
+          <label>Categories</label>
+          <p style={{ fontSize: '0.78rem', color: 'var(--text-muted)', margin: '0 0 8px' }}>
+            Primary category drives the main listing; additional categories place the question in every selected branch.
+          </p>
+          <select value={form.question_category_id} onChange={e => setForm(f => ({ ...f, question_category_id: e.target.value }))} aria-label="Primary category">
             <option value="">— Uncategorized —</option>
             {categories.map(c => <option key={c.id} value={c.id}>{(c.breadcrumbs || []).map(b => b.name).join(' › ') || c.name}</option>)}
           </select>
-        </div>
-        <div className="form-group">
-          <label>Additional subcategories</label>
-          <p style={{ fontSize: '0.78rem', color: 'var(--text-muted)', margin: '0 0 8px' }}>
-            A question can appear in several categories; the primary category stays the main one.
-          </p>
-          <div className="category-chips" role="group" aria-label="Additional subcategories">
-            {categories.filter(c => c.id !== (form.question_category_id ? parseInt(form.question_category_id) : null)).map(c => {
-              const checked = form.extraCategoryIds.includes(c.id)
-              return (
-                <label key={c.id} className={checked ? 'category-chip checked' : 'category-chip'}>
-                  <input type="checkbox" checked={checked} onChange={() => toggleExtra(c.id)} />
-                  {(c.breadcrumbs || []).map(b => b.name).join(' › ') || c.name}
-                </label>
-              )
-            })}
-          </div>
+          <CategoryTree
+            categories={categories}
+            selectedIds={form.extraCategoryIds}
+            excludedId={form.question_category_id ? parseInt(form.question_category_id) : null}
+            onToggle={toggleExtra}
+          />
         </div>
         <div className="form-group">
           <label>Key points (smart links to reading)</label>
@@ -650,6 +664,13 @@ export default function QuestionBankPage() {
   const [categories, setCategories] = useState([])
   const [searchQuery, setSearchQuery] = useState('')
   const [difficulty, setDifficulty] = useState('')
+  const [bankArticleIds, setBankArticleIds] = useState([])
+  const [articles, setArticles] = useState([])
+  const [collections, setCollections] = useState([])
+  useEffect(() => {
+    api.get('/articles/').then(res => setArticles(res.data || [])).catch(() => setArticles([]))
+    api.get('/collections/').then(res => setCollections(res.data || [])).catch(() => setCollections([]))
+  }, [])
   const [searchMode, setSearchMode] = useState('hybrid')
   const [filterCatIds, setFilterCatIds] = useState([])
   const [showUncategorized, setShowUncategorized] = useState(false)
@@ -716,7 +737,7 @@ export default function QuestionBankPage() {
     clearTimeout(debounceRef.current)
     debounceRef.current = setTimeout(() => loadQuestions(searchQuery, 0, filterCatIds, showUncategorized, showFavorites, searchMode, pageSize, selectedTagIds), 300)
     return () => clearTimeout(debounceRef.current)
-  }, [searchQuery, catIdsKey, showUncategorized, showFavorites, showMyQuestions, searchMode, pageSize, tagIdsKey, difficulty])
+  }, [searchQuery, catIdsKey, showUncategorized, showFavorites, showMyQuestions, searchMode, pageSize, tagIdsKey, difficulty, bankArticleIds.join(',')])
 
   const toggleTag = (tagId) => {
     setSelectedTagIds(prev => {
@@ -739,6 +760,7 @@ export default function QuestionBankPage() {
       const params = {}
       if (searchQuery.trim()) params.q = searchQuery.trim()
       if (difficulty) params.difficulty = difficulty
+      if (bankArticleIds.length) params.article_ids = bankArticleIds.join(',')
       if (filterCatIds.length > 0) params.category_ids = filterCatIds.join(',')
       if (showUncategorized) params.uncategorized = true
       if (showFavorites) params.favorites_only = true
@@ -916,7 +938,7 @@ export default function QuestionBankPage() {
         )
       })()}
 
-      {studyQuestion && <QuestionStudyModal question={studyQuestion} onClose={() => setStudyQuestion(null)}
+      {studyQuestion && <QuestionStudyModal question={studyQuestion} collections={collections} onClose={() => setStudyQuestion(null)}
         isFavorited={favorites.includes(studyQuestion.id)} onToggleFavorite={toggleFavorite} />}
       {editQuestion && <QuestionEditModal question={editQuestion} categories={categories}
         onSaved={updated => setQuestions(prev => prev.map(q => q.id === updated.id ? updated : q))}
@@ -1033,6 +1055,17 @@ export default function QuestionBankPage() {
             <option value="medium">Medium</option><option value="hard">Hard</option>
           </select>
         </label>
+        <h3>Articles</h3>
+        <div className="bank-articles">
+          {articles.map(article => (
+            <label key={article.id}>
+              <input type="checkbox" checked={bankArticleIds.includes(article.id)}
+                onChange={e => setBankArticleIds(ids => e.target.checked ? [...ids, article.id] : ids.filter(id => id !== article.id))} />
+              {article.title}
+            </label>
+          ))}
+          {articles.length === 0 && <p style={{ color: 'var(--text-muted)', fontSize: '.8rem' }}>No articles yet.</p>}
+        </div>
         <h3>Categories</h3>
         <div className="bank-category-list">
           {categories.map(cat => {
diff --git a/frontend/src/pages/QuestionBankPage.test.jsx b/frontend/src/pages/QuestionBankPage.test.jsx
index 4bdb8e0..7d2a7c1 100644
--- a/frontend/src/pages/QuestionBankPage.test.jsx
+++ b/frontend/src/pages/QuestionBankPage.test.jsx
@@ -217,12 +217,11 @@ describe('QuestionBankPage edit modal multi-category', () => {
     api.patch = vi.fn().mockResolvedValue({ data: {} })
     renderPage()
     await userEvent.click(await screen.findByRole('button', { name: 'Edit' }))
-    expect(await screen.findByRole('group', { name: 'Additional subcategories' })).toBeInTheDocument()
-    const extras = screen.getByRole('group', { name: 'Additional subcategories' })
-    expect(within(extras).getByLabelText('Cardiology')).toBeChecked()
-    expect(within(extras).getByLabelText('Renal')).not.toBeChecked()
-    expect(within(extras).queryByLabelText('Neonatology')).not.toBeInTheDocument()
-    await userEvent.click(within(extras).getByLabelText('Renal'))
+    const modal = await screen.findByRole('dialog', { name: 'Edit Question' })
+    expect(within(modal).getByLabelText(/Cardiology/)).toBeChecked()
+    expect(within(modal).getByLabelText(/Renal/)).not.toBeChecked()
+    expect(within(modal).getByLabelText(/Neonatology/)).toBeDisabled()
+    await userEvent.click(within(modal).getByLabelText(/Renal/))
     await userEvent.click(screen.getByRole('button', { name: 'Save Changes' }))
     await waitFor(() => expect(api.patch).toHaveBeenCalledWith('/questions/7', expect.objectContaining({
       additional_category_ids: [2, 3],
diff --git a/frontend/src/pages/QuizPage.jsx b/frontend/src/pages/QuizPage.jsx
index c39e4e4..3e5870f 100644
--- a/frontend/src/pages/QuizPage.jsx
+++ b/frontend/src/pages/QuizPage.jsx
@@ -423,6 +423,7 @@ export default function QuizPage() {
   const [resumedExpired, setResumedExpired] = useState(false)
   const [resumeRetry, setResumeRetry] = useState(0)
   const [progressError, setProgressError] = useState('')
+  const [restartConfirm, setRestartConfirm] = useState(false)
   const timerRef = useRef(null)
   const toastRef = useRef(null)
   const hasStarted = useRef(false)
@@ -637,7 +638,7 @@ export default function QuizPage() {
     return () => clearInterval(timerRef.current)
   }, [id, resumeRetry])
 
-  const startAttempt = async (mode, voice, timerMinutes = null) => {
+  const startAttempt = async (mode, voice, timerMinutes = null, fresh = false) => {
     hasStarted.current = true
     setSelectedVoice(voice)
     setStarting(true)
@@ -646,7 +647,7 @@ export default function QuizPage() {
 
     try {
       // Start attempt first (may select random question subset)
-      const attemptRes = await api.post(`/attempts/start?quiz_id=${id}&mode=${mode}`)
+      const attemptRes = await api.post(`/attempts/start?quiz_id=${id}&mode=${mode}${fresh ? '&fresh=true' : ''}`)
       mode = attemptRes.data.mode || mode
       setAttemptId(attemptRes.data.id)
       const aid = attemptRes.data.id
@@ -1044,6 +1045,21 @@ const timerStarted = timeLeft !== null
             <button className="btn btn-secondary btn-sm" onClick={() => setLeaveTarget(returnTo || '/')} title="Save progress and exit">
               ⏸ Suspend
             </button>
+            {restartConfirm ? (
+              <span className="quiz-restart-confirm" role="alert">Restart from the beginning?
+                <button className="btn btn-primary btn-sm" onClick={async () => {
+                  setRestartConfirm(false)
+                  setAnswers({}); setCurrentIdx(0); setDraftAnswer(''); setStartedAt(null)
+                  setTimeLeft(null); setTotalTime(null); setResponseStats(null); setStatsError('')
+                  setResumedExpired(false)
+                  hasStarted.current = false
+                  await startAttempt(quizMode || (quiz?.mode === 'timed' ? 'exam' : 'study'), selectedVoice || null, quiz?.time_limit_minutes || null, true)
+                }}>Yes, restart</button>
+                <button className="btn btn-secondary btn-sm" onClick={() => setRestartConfirm(false)}>Cancel</button>
+              </span>
+            ) : (
+              <button className="btn btn-secondary btn-sm" onClick={() => setRestartConfirm(true)} title="Start this quiz over from the beginning">↺ Restart</button>
+            )}
             {isModerator && <Link to={`/quizzes/${id}/edit`} className="btn btn-secondary btn-sm">✏️ Edit</Link>}
           </div>
         </div>
diff --git a/frontend/src/pages/QuizPlayer.css b/frontend/src/pages/QuizPlayer.css
index eaced57..c17ee8f 100644
--- a/frontend/src/pages/QuizPlayer.css
+++ b/frontend/src/pages/QuizPlayer.css
@@ -92,3 +92,4 @@
   .quiz-header-card { padding-bottom: 12px; }
   .quiz-response-stat { font-size: .7rem; }
 }
+.quiz-restart-confirm { display: inline-flex; align-items: center; gap: 6px; font-size: .8rem; color: var(--wrong-fg); background: var(--wrong-bg); border: 1px solid var(--wrong-bd); padding: 4px 10px; border-radius: 8px; }