diff --git a/backend/src/controllers/fileController.js b/backend/src/controllers/fileController.js
index cb644f0..74b35da 100644
--- a/backend/src/controllers/fileController.js
+++ b/backend/src/controllers/fileController.js
@@ -182,6 +182,15 @@ function uploadPersonalFile(req, res) {
     return res.status(400).json({ error: 'Содержимое файла не соответствует его расширению' });
   }
 
+  // Per-user storage quota: reject before the file becomes usable. Accounting
+  // is by student_materials.bytes (the uploaded file is not a material yet).
+  const used = db.prepare('SELECT COALESCE(SUM(bytes),0) AS b FROM student_materials WHERE user_id = ?').get(req.user.id);
+  const maxBytes = Number(process.env.MATERIALS_MAX_BYTES) || 300 * 1024 * 1024; // 300 MB
+  if (used.b + (req.file.size || 0) > maxBytes) {
+    try { fs.unlinkSync(filePath); } catch {}
+    return res.status(413).json({ error: 'Превышен лимит хранилища материалов' });
+  }
+
   res.status(201).json({ url: '/uploads/materials/' + req.file.filename });
 }
 
diff --git a/backend/src/controllers/studentMaterialsController.js b/backend/src/controllers/studentMaterialsController.js
index 0f7f6ca..60446c2 100644
--- a/backend/src/controllers/studentMaterialsController.js
+++ b/backend/src/controllers/studentMaterialsController.js
@@ -2,16 +2,64 @@
 /* Student-owned personal materials ("Мои материалы").
  * A user keeps copies of items saved from live lessons; the copies are
  * independent of the session lifecycle. */
+const fs = require('fs');
+const path = require('path');
 const db = require('../db/db');
 const { emit } = require('../sse');
 
 const KINDS = ['board', 'note', 'link', 'image'];
 
+// Personal uploads live here (mirrors fileController MATERIALS_DIR). Used for
+// reference-counted file cleanup when the material(s) pointing at a file go away.
+const MATERIALS_DIR = path.resolve(__dirname, '..', '..', 'uploads', 'materials');
+
+// Soft per-user cap on the number of materials. Read at call time so tests can
+// lower it via env. Byte quota is enforced separately at the upload endpoint.
+function maxItems() { return Number(process.env.MATERIALS_MAX_ITEMS) || 2000; }
+
+// Storable URLs are app-relative ("/…", not protocol-relative "//host") or
+// http(s). Everything else (javascript:, data:, mailto:, …) is rejected: a saved
+// link is rendered as <a href> on the owner's page AND can be handed out to a
+// whole class via /share, so a bad scheme would be stored XSS.
+// Returns the (length-capped) url, '' for empty, or undefined when invalid.
+function safeUrl(raw) {
+  const u = String(raw == null ? '' : raw).trim();
+  if (!u) return '';
+  if (/^https?:\/\//i.test(u)) return u.slice(0, 2000);
+  if (u[0] === '/' && u[1] !== '/') return u.slice(0, 2000);
+  return undefined;
+}
+
+// Bytes attributed to a material for quota accounting (server-measured).
+function measureBytes(kind, url, body) {
+  if (kind === 'note') return Buffer.byteLength(String(body || ''), 'utf8');
+  if ((kind === 'image' || kind === 'board') && typeof url === 'string' && url.startsWith('/uploads/materials/')) {
+    try { return fs.statSync(path.join(MATERIALS_DIR, path.basename(url))).size; } catch (e) { return 0; }
+  }
+  return 0;
+}
+
+// Reference-counted cleanup: unlink the file backing `url` only when NO material
+// row references it any more (share/annotate can alias one physical file across
+// rows). Call AFTER the delete/url-update so the freed row no longer counts.
+// No-op for non-local urls. Exported for tests.
+function releaseFileForUrl(url) {
+  if (typeof url !== 'string' || !url.startsWith('/uploads/materials/')) return;
+  if (db.prepare('SELECT 1 FROM student_materials WHERE url = ? LIMIT 1').get(url)) return;
+  const fp = path.join(MATERIALS_DIR, path.basename(url));
+  if (fp.startsWith(MATERIALS_DIR + path.sep)) { try { fs.unlinkSync(fp); } catch (e) { /* already gone */ } }
+}
+
 /* GET /api/materials — list the current user's saved materials + their collections */
 function list(req, res) {
   const uid = req.user.id;
+  // Return only a body PREVIEW (first 1000 chars) to keep the payload small for
+  // note-heavy users; the full text is fetched on demand via GET /:id. body_trunc
+  // tells the client a lazy fetch is needed before viewing/editing the note.
   const materials = db.prepare(`
-    SELECT id, kind, title, body, url, source_session_id, source_title, collection_id, tags, created_at
+    SELECT id, kind, title, substr(body, 1, 1000) AS body,
+           (CASE WHEN body IS NOT NULL AND length(body) > 1000 THEN 1 ELSE 0 END) AS body_trunc,
+           url, source_session_id, source_title, collection_id, tags, created_at
       FROM student_materials
      WHERE user_id = ?
      ORDER BY created_at DESC, id DESC
@@ -26,6 +74,19 @@ function list(req, res) {
   res.json({ materials, collections });
 }
 
+/* GET /api/materials/:id — one material with its FULL body (lazy-loaded by the
+   client when a note's preview was truncated). Owner-only. */
+function getOne(req, res) {
+  const row = db.prepare(`
+    SELECT id, user_id, kind, title, body, url, source_session_id, source_title, collection_id, tags, created_at
+      FROM student_materials WHERE id = ?
+  `).get(req.params.id);
+  if (!row) return res.status(404).json({ error: 'not found' });
+  if (row.user_id !== req.user.id) return res.status(403).json({ error: 'forbidden' });
+  delete row.user_id;
+  res.json(row);
+}
+
 /* Validate that a collection id belongs to the user; returns null if unset/invalid. */
 function ownCollectionId(raw, uid) {
   if (raw === null || raw === '' || raw === undefined) return null;
@@ -42,9 +103,16 @@ function create(req, res) {
   const kind = String(b.kind || '');
   if (!KINDS.includes(kind)) return res.status(400).json({ error: 'invalid kind' });
 
+  if (db.prepare('SELECT COUNT(*) AS n FROM student_materials WHERE user_id = ?').get(req.user.id).n >= maxItems())
+    return res.status(413).json({ error: 'Достигнут лимит числа материалов' });
+
   const title = String(b.title || '').slice(0, 300);
   const body  = b.body != null ? String(b.body).slice(0, 60000) : null;
-  const url   = b.url != null ? String(b.url).slice(0, 2000) : null;
+  let url = null;
+  if (b.url != null && b.url !== '') {
+    url = safeUrl(b.url);
+    if (url === undefined) return res.status(400).json({ error: 'Недопустимый адрес ссылки' });
+  }
   if ((kind === 'note') && !body) return res.status(400).json({ error: 'body required for note' });
   if ((kind === 'board' || kind === 'image' || kind === 'link') && !url)
     return res.status(400).json({ error: 'url required' });
@@ -58,38 +126,49 @@ function create(req, res) {
   const collectionId = ownCollectionId(b.collection_id, req.user.id);
   const tags = b.tags != null ? String(b.tags).slice(0, 500) : null;
 
+  const bytes = measureBytes(kind, url, body);
   const r = db.prepare(`
-    INSERT INTO student_materials (user_id, kind, title, body, url, source_session_id, source_title, collection_id, tags)
-    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
-  `).run(req.user.id, kind, title, body, url, sourceSessionId, sourceTitle, collectionId, tags);
+    INSERT INTO student_materials (user_id, kind, title, body, url, source_session_id, source_title, collection_id, tags, bytes)
+    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+  `).run(req.user.id, kind, title, body, url, sourceSessionId, sourceTitle, collectionId, tags, bytes);
   res.status(201).json({ id: Number(r.lastInsertRowid) });
 }
 
 /* PATCH /api/materials/:id — rename / edit one of the current user's items.
    Editable: title, body, url (e.g. re-saving an annotated image), collection_id, tags. */
 function update(req, res) {
-  const row = db.prepare('SELECT user_id FROM student_materials WHERE id = ?').get(req.params.id);
+  const row = db.prepare('SELECT user_id, url FROM student_materials WHERE id = ?').get(req.params.id);
   if (!row) return res.status(404).json({ error: 'not found' });
   if (row.user_id !== req.user.id) return res.status(403).json({ error: 'forbidden' });
   const b = req.body || {};
   const fields = [], args = [];
   if (b.title !== undefined) { fields.push('title = ?'); args.push(String(b.title || '').slice(0, 300)); }
   if (b.body  !== undefined) { fields.push('body = ?');  args.push(b.body != null ? String(b.body).slice(0, 60000) : null); }
-  if (b.url   !== undefined) { fields.push('url = ?');   args.push(b.url != null ? String(b.url).slice(0, 2000) : null); }
+  if (b.url   !== undefined) {
+    let nu = null;
+    if (b.url != null && b.url !== '') { nu = safeUrl(b.url); if (nu === undefined) return res.status(400).json({ error: 'Недопустимый адрес ссылки' }); }
+    fields.push('url = ?'); args.push(nu);
+  }
   if (b.collection_id !== undefined) { fields.push('collection_id = ?'); args.push(ownCollectionId(b.collection_id, req.user.id)); }
   if (b.tags !== undefined) { fields.push('tags = ?'); args.push(b.tags != null ? String(b.tags).slice(0, 500) : null); }
   if (!fields.length) return res.json({ ok: true });
   args.push(req.params.id);
   db.prepare(`UPDATE student_materials SET ${fields.join(', ')} WHERE id = ?`).run(...args);
+  // Recompute quota bytes from the persisted row; free the old file if the url
+  // changed (annotate overwrites url) and nothing else references it.
+  const cur = db.prepare('SELECT kind, url, body FROM student_materials WHERE id = ?').get(req.params.id);
+  db.prepare('UPDATE student_materials SET bytes = ? WHERE id = ?').run(measureBytes(cur.kind, cur.url, cur.body), req.params.id);
+  if (b.url !== undefined && row.url && row.url !== cur.url) releaseFileForUrl(row.url);
   res.json({ ok: true });
 }
 
 /* DELETE /api/materials/:id — remove one of the current user's items */
 function remove(req, res) {
-  const row = db.prepare('SELECT user_id FROM student_materials WHERE id = ?').get(req.params.id);
+  const row = db.prepare('SELECT user_id, url FROM student_materials WHERE id = ?').get(req.params.id);
   if (!row) return res.status(404).json({ error: 'not found' });
   if (row.user_id !== req.user.id) return res.status(403).json({ error: 'forbidden' });
   db.prepare('DELETE FROM student_materials WHERE id = ?').run(req.params.id);
+  releaseFileForUrl(row.url); // unlink the backing file if no other material aliases it
   res.json({ ok: true });
 }
 
@@ -164,12 +243,13 @@ function share(req, res) {
 
   const teacherName = (db.prepare('SELECT name FROM users WHERE id = ?').get(req.user.id) || {}).name || 'Учитель';
   const srcTitle = 'Раздатка: ' + teacherName;
-  const ins = db.prepare(`INSERT INTO student_materials (user_id, kind, title, body, url, source_session_id, source_title) VALUES (?,?,?,?,?,NULL,?)`);
+  const bytes = measureBytes(mat.kind, mat.url, mat.body); // each copy counts toward the recipient's quota
+  const ins = db.prepare(`INSERT INTO student_materials (user_id, kind, title, body, url, source_session_id, source_title, bytes) VALUES (?,?,?,?,?,NULL,?,?)`);
   let sent = 0;
   db.transaction(() => {
     for (const uid of recipients) {
       if (!uid || uid === req.user.id) continue;
-      ins.run(uid, mat.kind, mat.title, mat.body, mat.url, srcTitle);
+      ins.run(uid, mat.kind, mat.title, mat.body, mat.url, srcTitle, bytes);
       try {
         emit(uid, { type: 'notification', notif_type: 'material_shared',
           message: `Новый материал от ${teacherName}: «${mat.title || 'материал'}»`, link: '/my-materials' });
@@ -180,4 +260,6 @@ function share(req, res) {
   res.json({ ok: true, sent });
 }
 
-module.exports = { list, create, update, remove, createCollection, updateCollection, deleteCollection, share };
+module.exports = { list, getOne, create, update, remove, createCollection, updateCollection, deleteCollection, share,
+  // exported for tests / reuse
+  safeUrl, measureBytes, releaseFileForUrl };
diff --git a/backend/src/db/migrations/073_material_bytes.sql b/backend/src/db/migrations/073_material_bytes.sql
new file mode 100644
index 0000000..a18a2fd
--- /dev/null
+++ b/backend/src/db/migrations/073_material_bytes.sql
@@ -0,0 +1,12 @@
+-- ═══════════════════════════════════════════════════════════════
+-- 073: Storage accounting for «Мои материалы»
+--
+-- Per-material byte size, used to enforce a per-user storage quota and to free
+-- orphaned files. Populated on create/update:
+--   image|board → size of the file on disk (server-measured)
+--   note        → text length
+--   link        → 0
+-- Existing rows default to 0 (the next edit recomputes them; quota is a soft cap).
+-- ═══════════════════════════════════════════════════════════════
+
+ALTER TABLE student_materials ADD COLUMN bytes INTEGER NOT NULL DEFAULT 0;
diff --git a/backend/src/routes/materials.js b/backend/src/routes/materials.js
index 2090da4..d02d353 100644
--- a/backend/src/routes/materials.js
+++ b/backend/src/routes/materials.js
@@ -19,6 +19,8 @@ router.patch('/collections/:id',  c.updateCollection);
 // @public-by-design: router-level authMiddleware (above) + per-row ownership check in handler
 router.delete('/collections/:id', c.deleteCollection);
 
+// @public-by-design: router-level authMiddleware (above) + per-row ownership check in handler
+router.get('/:id',    c.getOne);
 // @public-by-design: router-level authMiddleware (above) + per-row ownership check in handler
 router.patch('/:id',  c.update);
 // @public-by-design: router-level authMiddleware (above) + per-row ownership check in handler
diff --git a/backend/tests/materials.test.js b/backend/tests/materials.test.js
new file mode 100644
index 0000000..8db988d
--- /dev/null
+++ b/backend/tests/materials.test.js
@@ -0,0 +1,197 @@
+'use strict';
+/**
+ * Integration tests: /api/materials — «Мои материалы» (v2 hardening).
+ * Covers: auth, CRUD happy-path, ownership (чужой PATCH/DELETE → 403, 404),
+ * collections (create / move / delete keeps material), share-копия (роль + owner
+ * + привязка ученика), URL-allowlist (javascript: → 400), лимит числа материалов,
+ * и ссылочно-подсчётную чистку файла (releaseFileForUrl на временном файле).
+ */
+const { describe, it, before, after } = require('node:test');
+const assert = require('node:assert/strict');
+const fs   = require('fs');
+const path = require('path');
+const { app, db, inject, getToken, cleanup } = require('./setup');
+
+// setup.js не монтирует /api/materials — монтируем на общий тест-app.
+app.use('/api/materials', require('../src/routes/materials'));
+const ctrl = require('../src/controllers/studentMaterialsController');
+
+after(() => cleanup());
+
+describe('/api/materials', () => {
+  let studentToken, studentId, otherToken, teacherToken, teacherId;
+
+  before(async () => {
+    const s = await getToken('student'); studentToken = s.token; studentId = s.userId;
+    otherToken = (await getToken('student')).token;
+    const t = await getToken('teacher'); teacherToken = t.token; teacherId = t.userId;
+  });
+
+  it('GET requires auth (401 without token)', async () => {
+    const res = await inject('GET', '/api/materials', null, null);
+    assert.equal(res.status, 401, `got ${res.status}`);
+  });
+
+  let noteId;
+  it('student can create a note (201) and list it back', async () => {
+    const c = await inject('POST', '/api/materials', { kind: 'note', title: 'Закон Ома', body: 'U=IR' }, studentToken);
+    assert.equal(c.status, 201, JSON.stringify(c.body));
+    noteId = c.body.id;
+    const l = await inject('GET', '/api/materials', null, studentToken);
+    assert.equal(l.status, 200);
+    assert.ok(l.body.materials.some(m => m.id === noteId && m.title === 'Закон Ома'));
+  });
+
+  it('accepts http(s) and app-relative link urls', async () => {
+    const a = await inject('POST', '/api/materials', { kind: 'link', url: 'https://example.com/x' }, studentToken);
+    assert.equal(a.status, 201, JSON.stringify(a.body));
+    const b = await inject('POST', '/api/materials', { kind: 'link', url: '/textbook/phys7#sec-1' }, studentToken);
+    assert.equal(b.status, 201, JSON.stringify(b.body));
+  });
+
+  it('rejects a link with javascript: scheme (400) — stored-XSS guard', async () => {
+    const res = await inject('POST', '/api/materials', { kind: 'link', url: 'javascript:alert(1)' }, studentToken);
+    assert.equal(res.status, 400, JSON.stringify(res.body));
+  });
+
+  it('rejects a protocol-relative url (400)', async () => {
+    const res = await inject('POST', '/api/materials', { kind: 'link', url: '//evil.example.com' }, studentToken);
+    assert.equal(res.status, 400, JSON.stringify(res.body));
+  });
+
+  it('PATCH cannot smuggle a javascript: url (400)', async () => {
+    const res = await inject('PATCH', `/api/materials/${noteId}`, { url: 'javascript:alert(1)' }, studentToken);
+    assert.equal(res.status, 400, JSON.stringify(res.body));
+  });
+
+  it('owner can rename; others get 403; missing → 404', async () => {
+    const ok = await inject('PATCH', `/api/materials/${noteId}`, { title: 'Ом' }, studentToken);
+    assert.equal(ok.status, 200);
+    const forbidden = await inject('PATCH', `/api/materials/${noteId}`, { title: 'hack' }, otherToken);
+    assert.equal(forbidden.status, 403);
+    const missing = await inject('PATCH', '/api/materials/999999', { title: 'x' }, studentToken);
+    assert.equal(missing.status, 404);
+  });
+
+  it('list returns a 1000-char body preview; GET /:id returns the full body (owner only)', async () => {
+    const big = 'x'.repeat(1500);
+    const c = await inject('POST', '/api/materials', { kind: 'note', body: big }, studentToken);
+    const id = c.body.id;
+    const l = await inject('GET', '/api/materials', null, studentToken);
+    const row = l.body.materials.find(m => m.id === id);
+    assert.equal(row.body.length, 1000, 'preview trimmed');
+    assert.equal(row.body_trunc, 1, 'truncation flagged');
+    const one = await inject('GET', `/api/materials/${id}`, null, studentToken);
+    assert.equal(one.status, 200);
+    assert.equal(one.body.body.length, 1500, 'full body returned');
+    assert.equal(one.body.user_id, undefined, 'user_id not leaked');
+    const forbidden = await inject('GET', `/api/materials/${id}`, null, otherToken);
+    assert.equal(forbidden.status, 403);
+    const missing = await inject('GET', '/api/materials/999999', null, studentToken);
+    assert.equal(missing.status, 404);
+  });
+
+  it('collections: create, move material in, delete keeps material (uncategorised)', async () => {
+    const col = await inject('POST', '/api/materials/collections', { name: 'Физика' }, studentToken);
+    assert.equal(col.status, 201, JSON.stringify(col.body));
+    const cid = col.body.id;
+    const mv = await inject('PATCH', `/api/materials/${noteId}`, { collection_id: cid }, studentToken);
+    assert.equal(mv.status, 200);
+    let l = await inject('GET', '/api/materials', null, studentToken);
+    assert.equal(l.body.materials.find(m => m.id === noteId).collection_id, cid);
+    assert.equal(l.body.collections.find(c => c.id === cid).count, 1);
+    const del = await inject('DELETE', `/api/materials/collections/${cid}`, null, studentToken);
+    assert.equal(del.status, 200);
+    l = await inject('GET', '/api/materials', null, studentToken);
+    assert.equal(l.body.materials.find(m => m.id === noteId).collection_id, null, 'material survives folder delete');
+  });
+
+  it('moving into another user\'s collection is ignored (collection_id stays null)', async () => {
+    const col = await inject('POST', '/api/materials/collections', { name: 'Чужая' }, otherToken);
+    const foreignCid = col.body.id;
+    const mv = await inject('PATCH', `/api/materials/${noteId}`, { collection_id: foreignCid }, studentToken);
+    assert.equal(mv.status, 200);
+    const l = await inject('GET', '/api/materials', null, studentToken);
+    assert.equal(l.body.materials.find(m => m.id === noteId).collection_id, null);
+  });
+
+  it('share: student is role-gated (403)', async () => {
+    const res = await inject('POST', `/api/materials/${noteId}/share`, { userId: studentId }, studentToken);
+    assert.equal(res.status, 403, JSON.stringify(res.body));
+  });
+
+  it('share: teacher → linked student copies the material; unlinked → 403', async () => {
+    const tNote = await inject('POST', '/api/materials', { kind: 'note', title: 'Раздатка', body: 'привет' }, teacherToken);
+    const tId = tNote.body.id;
+    // not linked yet
+    const denied = await inject('POST', `/api/materials/${tId}/share`, { userId: studentId }, teacherToken);
+    assert.equal(denied.status, 403, JSON.stringify(denied.body));
+    // link teacher → student, then share
+    db.prepare('INSERT INTO teacher_students (teacher_id, student_id) VALUES (?, ?)').run(teacherId, studentId);
+    const ok = await inject('POST', `/api/materials/${tId}/share`, { userId: studentId }, teacherToken);
+    assert.equal(ok.status, 200, JSON.stringify(ok.body));
+    assert.equal(ok.body.sent, 1);
+    const l = await inject('GET', '/api/materials', null, studentToken);
+    assert.ok(l.body.materials.some(m => m.title === 'Раздатка' && /Раздатка:/.test(m.source_title || '')), 'student received a copy');
+  });
+
+  it('enforces the per-user item cap (413)', async () => {
+    const q = await getToken('student');
+    const prev = process.env.MATERIALS_MAX_ITEMS;
+    process.env.MATERIALS_MAX_ITEMS = '3';
+    try {
+      for (let i = 0; i < 3; i++) {
+        const r = await inject('POST', '/api/materials', { kind: 'note', body: 'n' + i }, q.token);
+        assert.equal(r.status, 201, `create #${i}: ${JSON.stringify(r.body)}`);
+      }
+      const over = await inject('POST', '/api/materials', { kind: 'note', body: 'overflow' }, q.token);
+      assert.equal(over.status, 413, JSON.stringify(over.body));
+    } finally {
+      if (prev === undefined) delete process.env.MATERIALS_MAX_ITEMS; else process.env.MATERIALS_MAX_ITEMS = prev;
+    }
+  });
+
+  it('delete removes the row; owner only', async () => {
+    const m = await inject('POST', '/api/materials', { kind: 'note', body: 'temp' }, studentToken);
+    const id = m.body.id;
+    const forbidden = await inject('DELETE', `/api/materials/${id}`, null, otherToken);
+    assert.equal(forbidden.status, 403);
+    const ok = await inject('DELETE', `/api/materials/${id}`, null, studentToken);
+    assert.equal(ok.status, 200);
+    const l = await inject('GET', '/api/materials', null, studentToken);
+    assert.ok(!l.body.materials.some(x => x.id === id));
+  });
+
+  it('releaseFileForUrl: unlinks the file only when no material references it', () => {
+    const dir = path.join(__dirname, '..', 'uploads', 'materials');
+    fs.mkdirSync(dir, { recursive: true });
+    const fname = 'test_' + Date.now() + '.png';
+    const fpath = path.join(dir, fname);
+    const url = '/uploads/materials/' + fname;
+    fs.writeFileSync(fpath, Buffer.from([0x89, 0x50, 0x4e, 0x47]));
+    const ins = db.prepare('INSERT INTO student_materials (user_id, kind, url) VALUES (?, ?, ?)');
+    const r1 = ins.run(studentId, 'image', url).lastInsertRowid;
+    const r2 = ins.run(studentId, 'image', url).lastInsertRowid; // aliasing copy (как при share)
+
+    ctrl.releaseFileForUrl(url);
+    assert.ok(fs.existsSync(fpath), 'file kept while two rows reference it');
+
+    db.prepare('DELETE FROM student_materials WHERE id = ?').run(r1);
+    ctrl.releaseFileForUrl(url);
+    assert.ok(fs.existsSync(fpath), 'file kept while one row still references it');
+
+    db.prepare('DELETE FROM student_materials WHERE id = ?').run(r2);
+    ctrl.releaseFileForUrl(url);
+    assert.ok(!fs.existsSync(fpath), 'file unlinked once orphaned');
+  });
+
+  it('safeUrl / measureBytes behave as documented', () => {
+    assert.equal(ctrl.safeUrl('https://a.b/c'), 'https://a.b/c');
+    assert.equal(ctrl.safeUrl('/textbook/x'), '/textbook/x');
+    assert.equal(ctrl.safeUrl(''), '');
+    assert.equal(ctrl.safeUrl('javascript:x'), undefined);
+    assert.equal(ctrl.safeUrl('//host'), undefined);
+    assert.equal(ctrl.measureBytes('note', null, 'abc'), 3);
+    assert.equal(ctrl.measureBytes('link', 'https://x', null), 0);
+  });
+});
diff --git a/frontend/my-materials.html b/frontend/my-materials.html
index ceb3c4c..a0f04d1 100644
--- a/frontend/my-materials.html
+++ b/frontend/my-materials.html
@@ -70,6 +70,26 @@
     .mm-viewer-note { white-space: pre-wrap; word-break: break-word; line-height: 1.6; font-size: 0.9rem; color: var(--text-2); }
     .mm-empty { padding: 60px 20px; text-align: center; color: var(--text-3); }
     .mm-empty svg { width: 38px; height: 38px; opacity: 0.4; margin-bottom: 12px; }
+    .mm-tags { display: flex; flex-wrap: wrap; gap: 5px; margin-top: 8px; }
+    .mm-tag { font-size: .68rem; font-weight: 600; padding: 2px 8px; border-radius: 99px; background: rgba(6,182,212,0.12); color: #0891b2; cursor: pointer; transition: background .12s; }
+    .mm-tag:hover { background: rgba(6,182,212,0.24); }
+    .mm-src { color: var(--text-3); text-decoration: none; border-bottom: 1px dotted var(--text-3); }
+    .mm-src:hover { color: var(--violet); border-bottom-color: var(--violet); }
+    .mm-tagpill { display: inline-flex; align-items: center; gap: 4px; font-size: .76rem; font-weight: 600; padding: 6px 10px; border-radius: 9px; background: rgba(155,93,229,0.12); color: var(--violet); }
+    .mm-tagpill-x { display: inline-flex; cursor: pointer; }
+    .mm-tagpill-x svg { width: 13px; height: 13px; }
+    .mm-check { position: absolute; top: 10px; left: 10px; z-index: 3; width: 18px; height: 18px; cursor: pointer; accent-color: var(--violet); opacity: 0; transition: opacity .12s; }
+    .mm-card:hover .mm-check, .mm-check:checked { opacity: 1; }
+    .mm-card.mm-selected { border-color: var(--violet); box-shadow: 0 0 0 2px rgba(155,93,229,0.35); }
+    .mm-bulk { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin-bottom: 14px; padding: 10px 12px; border: 1px solid var(--violet); border-radius: 10px; background: rgba(155,93,229,0.06); }
+    .mm-bulk-count { font-weight: 700; font-size: .84rem; color: var(--violet); margin-right: auto; }
+    .mm-swatches { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 4px; }
+    .mm-swatch { width: 26px; height: 26px; border-radius: 8px; cursor: pointer; border: 2px solid transparent; box-shadow: inset 0 0 0 1px rgba(0,0,0,.08); }
+    .mm-swatch.on { border-color: var(--text); }
+    .mm-swatch-none { background: repeating-linear-gradient(45deg,#fff,#fff 4px,#e2e8f0 4px,#e2e8f0 8px); }
+    .mm-preview { min-height: 22px; padding: 8px 10px; border: 1px dashed var(--border); border-radius: 8px; font-size: .86rem; color: var(--text-2); background: rgba(148,163,184,0.06); white-space: pre-wrap; word-break: break-word; line-height: 1.5; }
+    .mm-preview:empty::before { content: 'Превью формул появится здесь…'; color: var(--text-3); }
+    @media (max-width: 768px) { .mm-check { opacity: .85; } }
     @media (max-width: 768px) {
       .mm-body { flex-direction: column; }
       .mm-rail { width: auto; position: static; flex-direction: row; overflow-x: auto; gap: 6px; padding-bottom: 4px; }
@@ -109,7 +129,15 @@
               <option value="note">Заметки</option>
               <option value="link">Ссылки</option>
             </select>
+            <select class="mm-kind" id="mm-sort" onchange="onSort(this.value)" title="Сортировка">
+              <option value="new">Сначала новые</option>
+              <option value="old">Сначала старые</option>
+              <option value="title">По названию</option>
+              <option value="kind">По типу</option>
+            </select>
+            <span id="mm-tagfilter"></span>
           </div>
+          <div id="mm-bulk" class="mm-bulk" style="display:none"></div>
           <div class="mm-grid" id="mm-grid"><div class="mm-empty">Загрузка…</div></div>
         </div>
       </div>
@@ -149,6 +177,9 @@
     }
     return tmp.innerHTML;
   }
+  /* Live formula preview for the note editor (renders $…$ as you type). */
+  function mmPreview(ta, prevId) { const p = document.getElementById(prevId); if (p) p.innerHTML = mathHtml(ta.value); }
+  window.mmPreview = mmPreview;
   function fmtDate(s) {
     if (!s) return '';
     try { const d = new Date(s.replace(' ', 'T') + (s.includes('Z') ? '' : 'Z'));
@@ -170,9 +201,39 @@
     if (u.startsWith('/lab'))      return 'Лаборатория';
     return 'Ссылка';
   }
+  function parseTags(s) { return String(s || '').split(',').map(t => t.trim()).filter(Boolean); }
+  /* Only trust folder colors that look like a hex value (guards inline-style injection). */
+  function safeColor(c) { return /^#[0-9a-fA-F]{3,8}$/.test(String(c || '')) ? c : ''; }
+
+  /* Meta line: source title links back to the originating lesson when known. */
+  function metaHtml(m) {
+    const date = fmtDate(m.created_at);
+    let src = '';
+    if (m.source_title) {
+      src = m.source_session_id
+        ? `<a class="mm-src" href="/my-lessons?session=${Number(m.source_session_id)}" title="Открыть исходный урок">${esc(m.source_title)}</a>`
+        : esc(m.source_title);
+      src += ' · ';
+    }
+    return src + esc(date);
+  }
+  /* Tag chips (click → filter). data-t carries the raw value, dodging JS-string injection. */
+  function tagsHtml(m) {
+    const tg = parseTags(m.tags);
+    if (!tg.length) return '';
+    return `<div class="mm-tags">${tg.map(t => `<span class="mm-tag" data-t="${esc(t)}" onclick="filterTag(this.dataset.t)">${esc(t)}</span>`).join('')}</div>`;
+  }
+  /* Lazy-load the full note body — the list endpoint returns only a 1000-char preview. */
+  async function ensureFullBody(m) {
+    if (!m || !m.body_trunc) return m;
+    try { const full = await LS.getMaterial(m.id); if (full && typeof full.body === 'string') { m.body = full.body; m.body_trunc = 0; } } catch (e) {}
+    return m;
+  }
+
   let _mats = [];
   let _cols = [];
-  const _filter = { col: 'all', kind: 'all', q: '' };
+  const _filter = { col: 'all', kind: 'all', q: '', sort: 'new', tag: '' };
+  const _sel = new Set();   // ids selected for bulk actions
 
   /* ── Move-to-collection select ── */
   function moveSelect(m) {
@@ -183,7 +244,10 @@
 
   function card(m) {
     const kind = KIND_LABEL[m.kind] || m.kind;
-    const meta = `${esc(m.source_title || '')}${m.source_title ? ' · ' : ''}${fmtDate(m.created_at)}`;
+    const meta = metaHtml(m);
+    const tags = tagsHtml(m);
+    const selCls = _sel.has(m.id) ? ' mm-selected' : '';
+    const cb = `<input type="checkbox" class="mm-check" ${_sel.has(m.id) ? 'checked' : ''} onclick="toggleSel(event,${m.id})" title="Выбрать" />`;
     const chip = `<span class="mm-kind-chip"><i data-lucide="${KIND_ICON[m.kind] || 'tag'}"></i>${kind}</span>`;
     const del  = `<button class="mm-btn danger" onclick="delMaterial(${m.id})" title="Удалить"><i data-lucide="trash-2"></i></button>`;
     const edit = `<button class="mm-btn" onclick="editMaterial(${m.id})" title="Изменить"><i data-lucide="pencil"></i></button>`;
@@ -196,12 +260,12 @@
     const mv   = moveSelect(m);
 
     if (m.kind === 'board' || m.kind === 'image') {
-      return `<div class="mm-card" draggable="true" ondragstart="mmDragStart(event,${m.id})" ondragend="mmDragEnd(event)">
+      return `<div class="mm-card${selCls}" draggable="true" ondragstart="mmDragStart(event,${m.id})" ondragend="mmDragEnd(event)">${cb}
         <a class="mm-card-media" href="${esc(m.url)}" onclick="openViewer(${m.id});return false;"><img src="${esc(m.url)}" alt="" loading="lazy" draggable="false"/></a>
         <div class="mm-card-body">
           ${chip}
           <div class="mm-card-title">${esc(m.title || kind)}</div>
-          <div class="mm-card-meta">${meta}</div>
+          <div class="mm-card-meta">${meta}</div>${tags}
           <div class="mm-card-actions">
             ${mv}
             <button class="mm-btn" onclick="openViewer(${m.id})" title="Просмотр"><i data-lucide="eye"></i></button>
@@ -213,7 +277,7 @@
     }
 
     if (m.kind === 'link') {
-      return `<div class="mm-card" draggable="true" ondragstart="mmDragStart(event,${m.id})" ondragend="mmDragEnd(event)">
+      return `<div class="mm-card${selCls}" draggable="true" ondragstart="mmDragStart(event,${m.id})" ondragend="mmDragEnd(event)">${cb}
         <a class="mm-card-link" href="${esc(m.url)}" target="_blank" rel="noopener" title="${esc(m.url)}">
           <span class="mm-card-link-ic"><i data-lucide="link"></i></span>
           <span class="mm-card-link-meta">
@@ -224,7 +288,7 @@
         <div class="mm-card-body">
           ${chip}
           <div class="mm-card-title">${esc(m.title || kind)}</div>
-          <div class="mm-card-meta">${meta}</div>
+          <div class="mm-card-meta">${meta}</div>${tags}
           <div class="mm-card-actions">
             ${mv}
             <a class="mm-btn primary" href="${esc(m.url)}" target="_blank" rel="noopener"><i data-lucide="external-link"></i> Открыть</a>
@@ -235,29 +299,31 @@
     }
 
     // note
-    return `<div class="mm-card" draggable="true" ondragstart="mmDragStart(event,${m.id})" ondragend="mmDragEnd(event)">
+    return `<div class="mm-card${selCls}" draggable="true" ondragstart="mmDragStart(event,${m.id})" ondragend="mmDragEnd(event)">${cb}
       <div class="mm-card-note">${mathHtml(m.body || '')}</div>
       <div class="mm-card-body">
         ${chip}
         <div class="mm-card-title">${esc(m.title || kind)}</div>
-        <div class="mm-card-meta">${meta}</div>
+        <div class="mm-card-meta">${meta}</div>${tags}
         <div class="mm-card-actions">${mv}${fc}${sh}${edit}${del}</div>
       </div>
     </div>`;
   }
 
   /* ── Folder rail (вертикальный список папок слева) ── */
-  function railItem(key, label, count, editId, droppable) {
+  function railItem(key, label, count, editId, droppable, color) {
     const active = _filter.col === key ? ' active' : '';
     const ed = editId
       ? `<span class="mm-rail-edit" onclick="event.stopPropagation();editCollection(${editId})" title="Изменить папку">${PENCIL}</span>`
       : '';
     const ic = key === 'all' ? 'inbox' : (key === 'none' ? 'folder-minus' : 'folder');
+    const tint = safeColor(color);
+    const icStyle = (tint && !active) ? ` style="color:${tint}"` : '';
     const drop = droppable
       ? ` ondragover="mmDragOver(event,this)" ondragleave="mmDragLeave(this)" ondrop="mmDrop(event,'${key}')"`
       : '';
     return `<div class="mm-rail-item${active}" onclick="setCol('${key}')"${drop}>
-      <i data-lucide="${ic}"></i>
+      <i data-lucide="${ic}"${icStyle}></i>
       <span class="mm-rail-label">${esc(label)}</span>
       <span class="mm-rail-count">${count}</span>${ed}
     </div>`;
@@ -266,7 +332,7 @@
     const bar = document.getElementById('mm-cols');
     const noneCount = _mats.filter(m => !m.collection_id).length;
     let html = railItem('all', 'Все', _mats.length, null, false);
-    _cols.forEach(c => { html += railItem(String(c.id), c.name, c.count, c.id, true); });
+    _cols.forEach(c => { html += railItem(String(c.id), c.name, c.count, c.id, true, c.color); });
     html += railItem('none', 'Без папки', noneCount, null, true);
     bar.innerHTML = html;
   }
@@ -299,17 +365,28 @@
   window.mmDragStart = mmDragStart; window.mmDragEnd = mmDragEnd;
   window.mmDragOver = mmDragOver;   window.mmDragLeave = mmDragLeave; window.mmDrop = mmDrop;
 
+  function sortRows(rows) {
+    const s = _filter.sort || 'new';
+    if (s === 'new') return rows;             // server already returns newest-first
+    const a = rows.slice();
+    if (s === 'old') a.reverse();
+    else if (s === 'title') a.sort((x, y) => (x.title || x.body || '').localeCompare(y.title || y.body || '', 'ru'));
+    else if (s === 'kind') a.sort((x, y) => (x.kind || '').localeCompare(y.kind || ''));
+    return a;
+  }
   function filtered() {
-    return _mats.filter(m => {
+    const rows = _mats.filter(m => {
       if (_filter.col === 'none' && m.collection_id) return false;
       if (_filter.col !== 'all' && _filter.col !== 'none' && String(m.collection_id) !== _filter.col) return false;
       if (_filter.kind !== 'all' && m.kind !== _filter.kind) return false;
+      if (_filter.tag && !parseTags(m.tags).includes(_filter.tag)) return false;
       if (_filter.q) {
         const hay = ((m.title || '') + ' ' + (m.body || '') + ' ' + (m.source_title || '') + ' ' + (m.url || '') + ' ' + (m.tags || '')).toLowerCase();
         if (!hay.includes(_filter.q)) return false;
       }
       return true;
     });
+    return sortRows(rows);
   }
 
   function renderGrid() {
@@ -327,6 +404,7 @@
       ? rows.map(card).join('')
       : `<div class="mm-empty" style="grid-column:1/-1"><i data-lucide="search-x"></i><p>Ничего не найдено</p></div>`;
     lucide.createIcons();
+    renderBulk();
   }
 
   async function load() {
@@ -336,6 +414,7 @@
       _cols = data.collections || [];
       renderCols();
       renderGrid();
+      renderTagFilter();
     } catch (e) {
       document.getElementById('mm-grid').innerHTML = `<div class="mm-empty" style="grid-column:1/-1">Ошибка загрузки</div>`;
     }
@@ -345,7 +424,63 @@
   function setCol(key) { _filter.col = key; renderCols(); renderGrid(); }
   function onKind(v)   { _filter.kind = v; renderGrid(); }
   function onSearch(v) { _filter.q = (v || '').trim().toLowerCase(); renderGrid(); }
+  function onSort(v)   { _filter.sort = v; renderGrid(); }
+  function filterTag(t) { _filter.tag = String(t || ''); renderTagFilter(); renderGrid(); }
+  function clearTag()  { _filter.tag = ''; renderTagFilter(); renderGrid(); }
+  function renderTagFilter() {
+    const el = document.getElementById('mm-tagfilter');
+    if (!el) return;
+    el.innerHTML = _filter.tag
+      ? `<span class="mm-tagpill">#${esc(_filter.tag)} <span class="mm-tagpill-x" onclick="clearTag()" title="Сбросить фильтр по тегу"><i data-lucide="x"></i></span></span>`
+      : '';
+    if (window.lucide) lucide.createIcons();
+  }
   window.setCol = setCol; window.onKind = onKind; window.onSearch = onSearch;
+  window.onSort = onSort; window.filterTag = filterTag; window.clearTag = clearTag;
+
+  /* ── Multi-select + bulk actions (reuse per-item endpoints) ── */
+  function renderBulk() {
+    const bar = document.getElementById('mm-bulk');
+    if (!bar) return;
+    const n = _sel.size;
+    if (!n) { bar.style.display = 'none'; bar.innerHTML = ''; return; }
+    const opts = ['<option value="__none">Без папки</option>']
+      .concat(_cols.map(c => `<option value="${c.id}">${esc(c.name)}</option>`)).join('');
+    bar.style.display = 'flex';
+    bar.innerHTML = `<span class="mm-bulk-count">Выбрано: ${n}</span>
+      <select class="mm-move" onchange="bulkMove(this.value)" title="Переместить выбранные"><option value="">Переместить в…</option>${opts}</select>
+      <button class="mm-btn danger" onclick="bulkDelete()"><i data-lucide="trash-2"></i> Удалить</button>
+      <button class="mm-btn" onclick="clearSel()"><i data-lucide="x"></i> Снять</button>`;
+    if (window.lucide) lucide.createIcons();
+  }
+  function toggleSel(e, id) {
+    e.stopPropagation();
+    const cb = e.target;
+    if (cb.checked) _sel.add(id); else _sel.delete(id);
+    const cardEl = cb.closest('.mm-card');
+    if (cardEl) cardEl.classList.toggle('mm-selected', cb.checked);
+    renderBulk();
+  }
+  function clearSel() { _sel.clear(); renderGrid(); }
+  async function bulkMove(v) {
+    if (v === '') return;
+    const cid = v === '__none' ? null : Number(v);
+    const ids = [..._sel];
+    try {
+      for (const id of ids) await LS.updateMaterial(id, { collection_id: cid });
+      _sel.clear(); load(); LS.toast('Перемещено: ' + ids.length, 'success');
+    } catch (e) { LS.toast(e.message || 'Ошибка', 'error'); }
+  }
+  async function bulkDelete() {
+    const ids = [..._sel];
+    if (!ids.length) return;
+    if (!await LS.confirm(`Будет удалено материалов: ${ids.length}. Действие необратимо.`, { title: 'Удалить выбранные?', confirmText: 'Удалить' })) return;
+    try {
+      for (const id of ids) await LS.deleteMaterial(id);
+      _sel.clear(); load(); LS.toast('Удалено: ' + ids.length, 'success');
+    } catch (e) { LS.toast(e.message || 'Ошибка', 'error'); }
+  }
+  window.toggleSel = toggleSel; window.clearSel = clearSel; window.bulkMove = bulkMove; window.bulkDelete = bulkDelete;
 
   /* ── Material actions ── */
   async function moveMaterial(id, cid) {
@@ -365,46 +500,56 @@
   function createNote() {
     const content = `<div style="display:flex;flex-direction:column;gap:10px">
       <input id="mm-nt-title" placeholder="Заголовок (необязательно)" style="${FLD}" />
-      <textarea id="mm-nt-body" rows="7" placeholder="Текст заметки…" style="${FLD};resize:vertical"></textarea>
+      <textarea id="mm-nt-body" rows="7" placeholder="Текст заметки… (поддерживается $формула$)" style="${FLD};resize:vertical" oninput="mmPreview(this,'mm-nt-prev')"></textarea>
+      <div id="mm-nt-prev" class="mm-preview"></div>
+      <input id="mm-nt-tags" placeholder="Теги через запятую (необязательно)" style="${FLD}" />
     </div>`;
     const m = LS.modal({ title: 'Новая заметка', content, size: 'sm', actions: [
       { label: 'Отмена', onClick: () => m.close() },
       { label: 'Создать', primary: true, onClick: async () => {
         const title = m.body.querySelector('#mm-nt-title').value.trim();
         const text  = m.body.querySelector('#mm-nt-body').value.trim();
+        const tags  = m.body.querySelector('#mm-nt-tags').value.trim() || null;
         if (!text && !title) { LS.toast('Введите текст заметки', 'warn'); return; }
         const col = _filter.col !== 'all' && _filter.col !== 'none' ? Number(_filter.col) : null;
-        try { await LS.saveMaterial({ kind: 'note', title, body: text, collection_id: col }); m.close(); load(); }
+        try { await LS.saveMaterial({ kind: 'note', title, body: text, collection_id: col, tags }); m.close(); load(); }
         catch (e) { LS.toast(e.message || 'Ошибка', 'error'); }
       } },
     ] });
   }
   window.createNote = createNote;
 
-  function editMaterial(id) {
+  async function editMaterial(id) {
     const mt = _mats.find(x => x.id === id);
     if (!mt) return;
     const isNote = mt.kind === 'note';
+    if (isNote) await ensureFullBody(mt);
     const content = `<div style="display:flex;flex-direction:column;gap:10px">
       <input id="mm-ed-title" value="${esc(mt.title || '')}" placeholder="Заголовок" style="${FLD}" />
-      ${isNote ? `<textarea id="mm-ed-body" rows="7" style="${FLD};resize:vertical">${esc(mt.body || '')}</textarea>` : ''}
+      ${isNote ? `<textarea id="mm-ed-body" rows="7" style="${FLD};resize:vertical" oninput="mmPreview(this,'mm-ed-prev')">${esc(mt.body || '')}</textarea><div id="mm-ed-prev" class="mm-preview"></div>` : ''}
+      <input id="mm-ed-tags" value="${esc(mt.tags || '')}" placeholder="Теги через запятую" style="${FLD}" />
     </div>`;
     const m = LS.modal({ title: 'Изменить', content, size: 'sm', actions: [
       { label: 'Отмена', onClick: () => m.close() },
       { label: 'Сохранить', primary: true, onClick: async () => {
-        const data = { title: m.body.querySelector('#mm-ed-title').value.trim() };
+        const data = {
+          title: m.body.querySelector('#mm-ed-title').value.trim(),
+          tags: m.body.querySelector('#mm-ed-tags').value.trim() || null,
+        };
         if (isNote) data.body = m.body.querySelector('#mm-ed-body').value;
         try { await LS.updateMaterial(id, data); m.close(); load(); }
         catch (e) { LS.toast(e.message || 'Ошибка', 'error'); }
       } },
     ] });
+    if (isNote) { const ta = m.body.querySelector('#mm-ed-body'); if (ta) mmPreview(ta, 'mm-ed-prev'); }
   }
   window.editMaterial = editMaterial;
 
   /* ── Просмотр материала в модалке (лайтбокс) ── */
-  function openViewer(id) {
+  async function openViewer(id) {
     const mt = _mats.find(x => x.id === id);
     if (!mt) return false;
+    if (mt.kind === 'note') await ensureFullBody(mt);
     const kind = KIND_LABEL[mt.kind] || mt.kind;
     let body;
     if (mt.kind === 'image' || mt.kind === 'board') {
@@ -431,24 +576,61 @@
   window.openViewer = openViewer;
 
   /* ── Collection CRUD ── */
+  const COL_PALETTE = ['#9b5de5', '#06b6d4', '#f97316', '#10b981', '#ef4444', '#eab308', '#3b82f6', '#ec4899'];
+  function colorPalette(sel) {
+    sel = safeColor(sel);
+    return `<div style="font-size:.78rem;color:var(--text-3)">Цвет</div>
+      <div class="mm-swatches">
+        <span class="mm-swatch mm-swatch-none${!sel ? ' on' : ''}" data-c="" onclick="pickSwatch(this)" title="Без цвета"></span>
+        ${COL_PALETTE.map(c => `<span class="mm-swatch${sel === c ? ' on' : ''}" data-c="${c}" style="background:${c}" onclick="pickSwatch(this)"></span>`).join('')}
+      </div>`;
+  }
+  function pickSwatch(el) { el.parentNode.querySelectorAll('.mm-swatch').forEach(s => s.classList.remove('on')); el.classList.add('on'); }
+  function pickedColor(body) { const on = body.querySelector('.mm-swatch.on'); return on ? (on.dataset.c || null) : null; }
+  window.pickSwatch = pickSwatch;
+
   function createCollection() {
-    const content = `<input id="mm-col-name" placeholder="Название папки" style="${FLD}" />`;
+    const content = `<div style="display:flex;flex-direction:column;gap:10px">
+      <input id="mm-col-name" placeholder="Название папки" style="${FLD}" />
+      ${colorPalette(null)}
+    </div>`;
     const m = LS.modal({ title: 'Новая папка', content, size: 'sm', actions: [
       { label: 'Отмена', onClick: () => m.close() },
       { label: 'Создать', primary: true, onClick: async () => {
         const name = m.body.querySelector('#mm-col-name').value.trim();
         if (!name) { LS.toast('Введите название', 'warn'); return; }
-        try { await LS.createMaterialCollection({ name }); m.close(); load(); }
+        try { await LS.createMaterialCollection({ name, color: pickedColor(m.body) }); m.close(); load(); }
         catch (e) { LS.toast(e.message || 'Ошибка', 'error'); }
       } },
     ] });
   }
   window.createCollection = createCollection;
 
+  /* Reorder a folder up/down by normalizing sort_order to the new index order. */
+  async function moveCollection(id, dir) {
+    const arr = _cols.slice();
+    const i = arr.findIndex(c => c.id === id);
+    const j = i + dir;
+    if (i < 0 || j < 0 || j >= arr.length) return;
+    [arr[i], arr[j]] = [arr[j], arr[i]];
+    try {
+      await Promise.all(arr.map((c, k) => c.sort_order !== k ? LS.updateMaterialCollection(c.id, { sortOrder: k }) : null).filter(Boolean));
+      load();
+    } catch (e) { LS.toast(e.message || 'Ошибка', 'error'); }
+  }
+  window.moveCollection = moveCollection;
+
   function editCollection(id) {
     const col = _cols.find(c => c.id === id);
     if (!col) return;
-    const content = `<input id="mm-col-name" value="${esc(col.name)}" placeholder="Название папки" style="${FLD}" />`;
+    const content = `<div style="display:flex;flex-direction:column;gap:10px">
+      <input id="mm-col-name" value="${esc(col.name)}" placeholder="Название папки" style="${FLD}" />
+      ${colorPalette(col.color)}
+      <div style="display:flex;gap:8px;margin-top:2px">
+        <button class="mm-btn" onclick="moveCollection(${id},-1)"><i data-lucide="arrow-up"></i> Выше</button>
+        <button class="mm-btn" onclick="moveCollection(${id},1)"><i data-lucide="arrow-down"></i> Ниже</button>
+      </div>
+    </div>`;
     const m = LS.modal({ title: 'Папка', content, size: 'sm', actions: [
       { label: 'Удалить', onClick: async () => {
         if (!await LS.confirm('Материалы из неё останутся и станут «Без папки».', { title: 'Удалить папку?', confirmText: 'Удалить' })) return;
@@ -459,10 +641,11 @@
       { label: 'Сохранить', primary: true, onClick: async () => {
         const name = m.body.querySelector('#mm-col-name').value.trim();
         if (!name) { LS.toast('Введите название', 'warn'); return; }
-        try { await LS.updateMaterialCollection(id, { name }); m.close(); load(); }
+        try { await LS.updateMaterialCollection(id, { name, color: pickedColor(m.body) }); m.close(); load(); }
         catch (e) { LS.toast(e.message || 'Ошибка', 'error'); }
       } },
     ] });
+    if (window.lucide) lucide.createIcons();
   }
   window.editCollection = editCollection;
 
@@ -525,6 +708,7 @@
   async function toFlashcard(id) {
     const mt = _mats.find(x => x.id === id);
     if (!mt) return;
+    await ensureFullBody(mt);
     let decks = [];
     try { const d = await LS.fcListDecks(); decks = d.decks || []; } catch (e) {}
     const opts = ['<option value="__new">+ Новая колода «Из материалов»</option>']
diff --git a/js/api.js b/js/api.js
index 4f19df5..5452359 100644
--- a/js/api.js
+++ b/js/api.js
@@ -1037,7 +1037,7 @@ window.LS = {
   crJoin, crLeave, crSendChat, crGetChat, crGetAttendance, crSignal, crGetOnlineStudents, crGetMySession,
   crGetMyHistory, crGetClassHistory, crGetSessionSummary, crExportChatUrl, crGetAllNotes, crDeleteHistory,
   crAdminGetAllHistory, crAdminGetTeachersList,
-  listMaterials, saveMaterial, updateMaterial, deleteMaterial, shareMaterial, getActivity,
+  listMaterials, getMaterial, saveMaterial, updateMaterial, deleteMaterial, shareMaterial, getActivity,
   createMaterialCollection, updateMaterialCollection, deleteMaterialCollection,
   customSimsList, customSimGet, customSimCreate, customSimUpdate, customSimDelete,
   customSimShare, customSimClone, customSimRelated, customSimAddLink, customSimDelLink,
@@ -1253,6 +1253,7 @@ async function uploadMaterialFile(formData) {
 }
 function downloadFileUrl(id) { return `${API}/files/${id}/download`; }
 async function listMaterials()        { return req('GET',    '/materials'); }
+async function getMaterial(id)        { return req('GET',    `/materials/${id}`); }
 async function saveMaterial(data)     { return req('POST',   '/materials', data); }
 async function updateMaterial(id, d)  { return req('PATCH',  `/materials/${id}`, d); }
 async function deleteMaterial(id)     { return req('DELETE', `/materials/${id}`); }
diff --git a/plans/my-materials/PLAN_V2.md b/plans/my-materials/PLAN_V2.md
new file mode 100644
index 0000000..2e37408
--- /dev/null
+++ b/plans/my-materials/PLAN_V2.md
@@ -0,0 +1,57 @@
+# «Мои материалы» — v2: харднинг и доводка
+
+> Составлен Opus 2026-06-13. Базовый план (PLAN.md, Фазы 1–6) **полностью реализован**.
+> Его раздел «Сквозные риски» отложил ровно то, что закрывает этот план: учёт/лимиты/чистку
+> хранилища и `materials.test.js`. Источник истины по текущему состоянию — код
+> (`studentMaterialsController.js`, `materials.js`, `my-materials.html`, `board-clip.js`,
+> `material-save.js`) и [[reference_student_materials]].
+
+Готчи проекта: новый `:id`-роут → `// @public-by-design` + проверка владельца; большие HTML — только Edit;
+без эмодзи (inline SVG `.ic`); коммит поимённо + push; перезапуск сервера при правке backend; ветка
+`feature/sim-builder` в рабочем дереве — НЕ коммитить чужие правки, только свои файлы.
+
+---
+
+## Фаза 1 — Целостность и безопасность (backend, фундамент)  ✅ цель этого захода
+
+1. **Ссылочно-подсчётная чистка файлов.** `DELETE /:id` и смена `url` (аннотация) сейчас оставляют
+   файл в `uploads/materials/` сиротой. `share` копирует `url` дословно → несколько строк ссылаются на
+   ОДИН файл, поэтому `unlink` только когда на `url` не ссылается ни одна строка. Хелпер
+   `releaseFileForUrl(url)` вызывается ПОСЛЕ delete/update.
+2. **Allowlist схемы URL.** `create`/`update` принимали любой `url` → `link` со схемой `javascript:`
+   рендерится как рабочий `<a href>` (раздача делает это вектором учитель→ученики). Хелпер `safeUrl`:
+   только `http(s)://` или app-relative `/…` (не `//host`); иначе 400.
+3. **Квота на пользователя.** Колонка `bytes` (мигр. 073), счёт `SUM(bytes)`/`COUNT(*)`. Лимит по числу
+   материалов — в `create()`; лимит по байтам — в `uploadPersonalFile` (до приёма файла). Конфигурируемо
+   через `MATERIALS_MAX_ITEMS` / `MATERIALS_MAX_BYTES` (для тестов — низкий потолок).
+4. **`backend/tests/materials.test.js`** — CRUD, владелец (403/404), коллекции, share-копия + роль/owner,
+   валидация URL, лимит числа, ссылочная чистка (прямой вызов хелпера на временном файле).
+
+## Фаза 2 — Производительность  ✅ (частично)
+- ✅ `GET /api/materials` отдаёт **обрезанный** `body` (первые 1000 симв.) + флаг `body_trunc`; полный текст —
+  ленивый `GET /api/materials/:id` (`getOne`, owner-only). Клиент `ensureFullBody()` подгружает перед
+  просмотром/правкой/флешкартой (иначе правка сохранила бы усечённый текст).
+- ⬜ Пагинация/keyset — отложено (клиент пока фильтрует в памяти; включить при росте объёмов).
+- ⬜ Серверные миниатюры `board/image` — отложено (нужна обработка картинок; пока `loading=lazy`).
+
+## Фаза 3 — Доводка заложенных фич  ✅
+- ✅ UI тегов: ввод в модалках создания/правки + чипы на карточке (клик → фильтр) + пилюля активного фильтра.
+- ✅ Ссылка «открыть исходный урок» на карточке (`/my-lessons?session=<id>`, есть `source_session_id`).
+- ✅ Цвет папки (палитра 8 пресетов, тинт иконки в рейле) + сортировка папок «Выше/Ниже» в модалке правки
+  (нормализует `sort_order` к индексам). `safeColor` гейтит inline-style инъекцию (только hex).
+
+## Фаза 4 — UX  ✅
+- ✅ Варианты сортировки (новые/старые/имя/тип) — селект в тулбаре.
+- ✅ Множественный выбор (чекбокс на карточке) + панель массовых действий (переместить/удалить, reuse per-item API).
+- ✅ Живое превью KaTeX в редакторе заметки (oninput → `mmPreview` → `mathHtml`).
+
+### Статус
+Сделано и проверено: **Ф1 целиком** (16 backend-тестов), **Ф2/Ф3/Ф4 ✅** (headless-смоук `my-materials.html`:
+синтаксис + рендер карточек с deep-link/тегами/чекбоксом + фильтр по тегу + bulk-bar + тинт папки).
+Осталось ⬜ (инфра, отложено): пагинация/keyset списка, серверные миниатюры board/image.
+
+---
+
+## Порядок
+**Ф1 (этот заход) → Ф2 → Ф3 → Ф4.** Ф1 — серверный фундамент (риск-возврат, без него фронт-фичи множат
+мусор). Дальше преимущественно фронтенд `my-materials.html` + точечные ручки API.