diff --git a/examples/content/dasar/composite_test.md b/examples/content/dasar/composite_test.md
new file mode 100644
index 0000000..5f85678
--- /dev/null
+++ b/examples/content/dasar/composite_test.md
@@ -0,0 +1,108 @@
+---LESSON_INFO---
+**Learning Objectives:**
+- Memahami konsep materi komposit di Elemes (latihan koding + kuis)
+- Menyelesaikan latihan program C/Python dan kuis evaluasi pemahaman
+**Prerequisites:**
+- variabel
+---END_LESSON_INFO---
+
+# Uji Coba Komposit (Latihan dan Kuis)
+
+Pelajaran ini merupakan contoh materi **komposit**, yaitu materi pembelajaran yang menggabungkan:
+1. **Latihan Pemrograman (Exercise):** Menulis kode program langsung di editor dan memverifikasi keluarannya.
+2. **Kuis Evaluasi (Quiz):** Menjawab pertanyaan pilihan ganda terkait materi.
+
+### Perhitungan Nilai Komposit
+Nilai akhir siswa dihitung dari kombinasi kedua komponen:
+- Bobot Latihan: 70%
+- Bobot Kuis: 30%
+- Ambang Tuntas (*Done*): $\ge$ 75%
+
+---EXERCISE---
+### Latihan: Pengecekan Angka Positif
+Buatlah program yang memeriksa nilai variabel `angka`. Jika `angka > 0`, cetak:
+```
+Positif
+```
+
+---INITIAL_CODE---
+#include <stdio.h>
+
+int main() {
+    int angka = 10;
+    // Tulis logika percabangan if di bawah ini:
+    if (angka > 0) {
+        printf("Positif\n");
+    }
+    return 0;
+}
+---END_INITIAL_CODE---
+
+---EXPECTED_OUTPUT---
+Positif
+---END_EXPECTED_OUTPUT---
+
+---INITIAL_PYTHON---
+angka = 10
+# Tulis logika percabangan if di bawah ini:
+if angka > 0:
+    print("Positif")
+---END_INITIAL_PYTHON---
+
+---EXPECTED_OUTPUT_PYTHON---
+Positif
+---END_EXPECTED_OUTPUT_PYTHON---
+
+---SOLUTION_CODE---
+#include <stdio.h>
+
+int main() {
+    int angka = 10;
+    if (angka > 0) {
+        printf("Positif\n");
+    }
+    return 0;
+}
+---END_SOLUTION_CODE---
+
+---SOLUTION_PYTHON---
+angka = 10
+if angka > 0:
+    print("Positif")
+---END_SOLUTION_PYTHON---
+
+---KEY_TEXT---
+if
+printf
+print
+---END_KEY_TEXT---
+
+---QUIZ_FLASHCARD---
+### Manakah sintaks penulisan kondisi `if` yang benar dalam bahasa C?
+- [x] `if (kondisi) { ... }`
+- [] `if kondisi then { ... }`
+- [] `if [kondisi] { ... }`
+- [] `if {kondisi} then { ... }`
+> Penjelasan: Dalam bahasa C, ekspresi logika kondisi pada `if` wajib berada di dalam tanda kurung biasa `( )`.
+
+### Apa keluaran dari kode berikut jika `x = 5`?
+```c
+if (x > 10) {
+    printf("Besar\n");
+} else {
+    printf("Kecil\n");
+}
+```
+- [] Besar
+- [x] Kecil
+- [] Error sintaks
+- [] Tidak ada keluaran
+> Penjelasan: Karena `5 > 10` bernilai salah (false), maka blok `else` yang akan dieksekusi, menghasilkan output "Kecil".
+
+### Berapa bobot penilaian komponen latihan koding dalam penentuan nilai komposit standar Elemes?
+- [] 30%
+- [] 50%
+- [x] 70%
+- [] 100%
+> Penjelasan: Secara default pada konfigurasi Elemes, komponen latihan koding memiliki bobot 70% dan kuis memiliki bobot 30%.
+---END_QUIZ_FLASHCARD---
diff --git a/examples/content/dasar/sub-home.md b/examples/content/dasar/sub-home.md
index c56be2d..9399b5e 100644
--- a/examples/content/dasar/sub-home.md
+++ b/examples/content/dasar/sub-home.md
@@ -9,5 +9,6 @@ Materi fundamental untuk memulai belajar pemrograman C.
 4. [Uji Coba Kuis](lesson/quiz_test.md)
 5. [Uji Coba LaTeX](lesson/latex_test.md)
 6. [Uji Coba Slide](lesson/test_slides.md)
+7. [Uji Coba Komposit](lesson/composite_test.md)
 
 
diff --git a/frontend/src/routes/teacher/progress/+page.svelte b/frontend/src/routes/teacher/progress/+page.svelte
index 8ab2095..64ed021 100644
--- a/frontend/src/routes/teacher/progress/+page.svelte
+++ b/frontend/src/routes/teacher/progress/+page.svelte
@@ -56,7 +56,9 @@
 
 		loading = true;
 		try {
-			const res = await fetch(`/api/progress-report.json?token=${encodeURIComponent($authToken)}`);
+			const res = await fetch(`/api/progress-report.json?token=${encodeURIComponent($authToken)}&_t=${Date.now()}`, {
+				cache: 'no-store'
+			});
 			const data = await res.json();
 			students = data.students ?? [];
 			lessons = data.lessons ?? [];
@@ -286,6 +288,7 @@
 							</td>
 							{#each lessons as lesson}
 								{@const key = lesson.filename.replace('.md', '')}
+								{@const status = student[key]}
 								{@const composite = student[key + '_composite']}
 								{@const exercisePassed = student[key + '_exercise_passed']}
 								{@const quizScore = student[key + '_quiz_score']}
@@ -305,6 +308,10 @@
 											{#if quizScore}
 												<span class="badge quiz-score" title="Skor quiz">{quizScore}</span>
 											{/if}
+										{:else if status === 'completed'}
+											<span class="badge exercise-done" title="Selesai">&#10003;</span>
+										{:else if status && status !== 'not_started'}
+											<span class="badge score" title="Status progres">{status}</span>
 										{:else}
 											<span class="badge empty">&mdash;</span>
 										{/if}
@@ -333,7 +340,7 @@
 											{/if}
 										{/if}
 
-										{#if composite !== null && composite !== undefined}
+										{#if (composite !== null && composite !== undefined) || (status && status !== 'not_started')}
 											<button
 												class="btn-reset-mini"
 												onclick={() => handleReset(student.id as string, key, student.nama_siswa)}
diff --git a/routes/progress.py b/routes/progress.py
index 90c8108..03e0ef0 100644
--- a/routes/progress.py
+++ b/routes/progress.py
@@ -85,10 +85,12 @@ def api_progress_report():
         get_lessons_with_learning_objectives,
     )
 
-    return jsonify({
+    resp = jsonify({
         'students': all_students_progress,
         'lessons': [{'filename': l['filename'], 'title': l['title']} for l in ordered_lessons],
     })
+    resp.headers['Cache-Control'] = 'no-store, no-cache, must-revalidate, max-age=0'
+    return resp
 
 
 @progress_bp.route('/progress-report/export-csv')
diff --git a/services/lesson_service.py b/services/lesson_service.py
index 2ee838e..64bf286 100644
--- a/services/lesson_service.py
+++ b/services/lesson_service.py
@@ -1304,3 +1304,35 @@ def get_lesson_components(lesson_name: str) -> tuple[bool, bool]:
     has_quiz = "quiz" in tabs
     return (has_exercise, has_quiz)
 
+
+def get_lesson_quiz_total(lesson_name: str) -> int | None:
+    """Kembalikan jumlah soal kuis untuk lesson jika ada, atau None."""
+    file_path = find_lesson_file(f"{lesson_name}.md")
+    if not file_path:
+        return None
+    try:
+        parsed = render_markdown_content(file_path)
+        quiz_data = parsed.get("quiz_data") or []
+        return len(quiz_data) if quiz_data else None
+    except Exception:
+        return None
+
+
+def get_lesson_expected_format(lesson_name: str) -> str:
+    """Tentukan panduan expected format kolom lesson berdasarkan komponennya.
+
+    - Exercise only: 'completed'
+    - Quiz only: '<earned>/N' jika total soal diketahui, atau '<earned>/<total>'
+    - Exercise + Quiz: 'done:<1|0>:<earned>/N' (atau '<total>')
+    - Reading only: 'completed'
+    """
+    has_exercise, has_quiz = get_lesson_components(lesson_name)
+    quiz_total = get_lesson_quiz_total(lesson_name) if has_quiz else None
+    if has_exercise and has_quiz:
+        q_fmt = f"<earned>/{quiz_total}" if quiz_total else "<earned>/<total>"
+        return f"done:<1|0>:{q_fmt}"
+    if has_quiz:
+        return f"<earned>/{quiz_total}" if quiz_total else "<earned>/<total>"
+    return "completed"
+
+
diff --git a/services/repositories.py b/services/repositories.py
index ddcec6c..24e8b16 100644
--- a/services/repositories.py
+++ b/services/repositories.py
@@ -17,7 +17,7 @@ from sqlalchemy.orm import Session
 from config import LESSON_EXERCISE_WEIGHT, LESSON_QUIZ_WEIGHT, LESSON_DONE_MIN_PERCENT
 from services.models import AccessToken, ContentDraft, Lesson, QuizAttempt, StudentProgress, User
 from services.evaluation import compute_composite
-from services.lesson_service import get_lesson_components
+from services.lesson_service import get_lesson_components, get_lesson_quiz_total
 from services.progress_status import ParsedProgress
 from services.student_roundtrip import (
     RoundTripImportError,
@@ -483,6 +483,24 @@ def list_students_for_export(
     )
 
 
+def get_lesson_expected_format(slug: str) -> str:
+    """Tentukan panduan expected format kolom lesson berdasarkan komponennya.
+
+    - Exercise only: 'completed'
+    - Quiz only: '<earned>/N' jika total soal diketahui, atau '<earned>/<total>'
+    - Exercise + Quiz: 'done:<1|0>:<earned>/N' (atau '<total>')
+    - Reading only: 'completed'
+    """
+    has_exercise, has_quiz = get_lesson_components(slug)
+    quiz_total = get_lesson_quiz_total(slug) if has_quiz else None
+    if has_exercise and has_quiz:
+        q_fmt = f"<earned>/{quiz_total}" if quiz_total else "<earned>/<total>"
+        return f"done:<1|0>:{q_fmt}"
+    if has_quiz:
+        return f"<earned>/{quiz_total}" if quiz_total else "<earned>/<total>"
+    return "completed"
+
+
 def export_students_csv(
     db: Session,
     student_ids: list[str] | None = None,
@@ -490,10 +508,15 @@ def export_students_csv(
     """Export siswa (selection atau seluruh) + progress → CSV round-trip bytes.
 
     Kolom token selalu kosong; teacher tidak pernah ikut; export tidak mengubah DB.
+    Header kolom lesson dilengkapi format yang diharapkan (mis. 'hello_world [completed]').
     """
     users = list_students_for_export(db, student_ids)
     lessons = list_active_lessons(db)
     lesson_slugs = [lesson.slug for lesson in lessons]
+    lesson_headers = {
+        lesson.slug: f"{lesson.slug} [{get_lesson_expected_format(lesson.slug)}]"
+        for lesson in lessons
+    }
 
     rows: list[StudentRoundTripRow] = []
     for user in users:
@@ -527,7 +550,7 @@ def export_students_csv(
                 progress=progress,
             )
         )
-    return serialize_export_csv(rows, lesson_slugs)
+    return serialize_export_csv(rows, lesson_slugs, lesson_headers=lesson_headers)
 
 
 def find_student_import_conflicts(
@@ -707,6 +730,47 @@ def run_student_import(
                         quiz_weight=LESSON_QUIZ_WEIGHT,
                         done_min_percent=LESSON_DONE_MIN_PERCENT,
                     )
+                elif parsed.state == "completed":
+                    has_exercise, has_quiz = get_lesson_components(slug)
+                    progress = set_progress(
+                        db,
+                        user_id=user.id,
+                        lesson_id=lesson.id,
+                        state="completed",
+                    )
+                    if progress is not None:
+                        if has_exercise:
+                            progress.exercise_passed = True
+                        progress.composite_percent = 100.0
+                        db.flush()
+                elif parsed.state == "scored":
+                    has_exercise, has_quiz = get_lesson_components(slug)
+                    effective_has_quiz = has_quiz or (
+                        parsed.score_total is not None and parsed.score_total > 0
+                    )
+                    progress = set_progress(
+                        db,
+                        user_id=user.id,
+                        lesson_id=lesson.id,
+                        state="scored",
+                        score_earned=parsed.score_earned,
+                        score_total=parsed.score_total,
+                    )
+                    if progress is not None:
+                        progress.quiz_score_earned = parsed.score_earned
+                        progress.quiz_score_total = parsed.score_total
+                        result = compute_composite(
+                            exercise_passed=progress.exercise_passed,
+                            quiz_earned=progress.quiz_score_earned,
+                            quiz_total=progress.quiz_score_total,
+                            has_exercise=has_exercise,
+                            has_quiz=effective_has_quiz,
+                            exercise_weight=LESSON_EXERCISE_WEIGHT,
+                            quiz_weight=LESSON_QUIZ_WEIGHT,
+                            done_min_percent=LESSON_DONE_MIN_PERCENT,
+                        )
+                        progress.composite_percent = result.composite_percent
+                        db.flush()
                 elif parsed.state == "reset":
                     set_progress(db, user_id=user.id, lesson_id=lesson.id, state="not_started")
                     progress_reset += 1
diff --git a/services/student_roundtrip.py b/services/student_roundtrip.py
index ac4d9f2..c1b922c 100644
--- a/services/student_roundtrip.py
+++ b/services/student_roundtrip.py
@@ -172,6 +172,40 @@ def _row_is_empty(record: dict) -> bool:
     return all(not (v or "").strip() for v in record.values())
 
 
+def extract_slug_from_header(header: str, active_slugs: set[str] | None = None) -> str:
+    """Ekstrak slug lesson canonical dari nama kolom header.
+
+    Mendukung format:
+    - Bare slug: "hello_world"
+    - Slug + expected format: "hello_world [completed]", "quiz_test [<earned>/4]"
+    - Title + (slug) + format: "Hello World (hello_world) [completed]"
+    - Title + (slug): "Hello World (hello_world)"
+    """
+    raw = (header or "").strip()
+    if not raw:
+        return ""
+    if active_slugs and raw in active_slugs:
+        return raw
+
+    # 1. Hapus kurung siku [expected format] di akhir bila ada
+    base = raw
+    if base.endswith("]") and "[" in base:
+        base = base[: base.rfind("[")].strip()
+
+    if active_slugs and base in active_slugs:
+        return base
+
+    # 2. Bila ada kurung biasa (slug) di akhir: "Title (slug)"
+    if base.endswith(")") and "(" in base:
+        inside = base[base.rfind("(") + 1 : -1].strip()
+        if active_slugs and inside in active_slugs:
+            return inside
+        if inside:
+            return inside
+
+    return base
+
+
 def parse_roundtrip_csv(
     content: str | bytes,
     active_lesson_slugs: list[str] | set[str],
@@ -226,14 +260,20 @@ def parse_roundtrip_csv(
             errors.append(f"Header duplikat: {col!r}")
         seen_headers.add(col)
 
-    lesson_columns: list[str] = []
+    header_to_slug: dict[str, str] = {}
+    seen_slugs: set[str] = set()
     for col in fieldnames:
         if col in REQUIRED_COLUMNS:
             continue
-        if col not in active:
+        slug = extract_slug_from_header(col, active)
+        if slug not in active:
             errors.append(f"Kolom lesson tidak dikenal atau tidak aktif: {col!r}")
             continue
-        lesson_columns.append(col)
+        if slug in seen_slugs:
+            errors.append(f"Header duplikat untuk lesson: {col!r}")
+            continue
+        seen_slugs.add(slug)
+        header_to_slug[col] = slug
 
     if errors:
         raise RoundTripImportError(errors)
@@ -322,12 +362,12 @@ def parse_roundtrip_csv(
 
         # progress per lesson
         progress: dict[str, ParsedProgress] = {}
-        for slug in lesson_columns:
-            value = record.get(slug) or ""
+        for col, slug in header_to_slug.items():
+            value = record.get(col) or ""
             try:
                 parsed = parse_roundtrip_cell(value)
             except ValueError as exc:
-                errors.append(f"Baris {line}, kolom {slug}: {exc}")
+                errors.append(f"Baris {line}, kolom {col}: {exc}")
                 continue
             if parsed is not None:
                 progress[slug] = parsed
@@ -350,15 +390,23 @@ def parse_roundtrip_csv(
 def serialize_export_csv(
     rows: list[StudentRoundTripRow],
     lesson_slugs: list[str],
+    lesson_headers: dict[str, str] | None = None,
 ) -> bytes:
     """Serialize row export → CSV UTF-8 BOM, delimiter ';', token selalu kosong.
 
     - Baris pertama: legend grammar sel progress (# Format kolom lesson...).
-    - Header: student_id;token;nama_siswa;<lesson_slugs...> sesuai urutan.
+    - Header: student_id;token;nama_siswa;<lesson_headers...> sesuai urutan.
     - Status ditulis dengan grammar roundtrip (kosong/completed/<earned>/<total>/done:...).
     - `completed_count`, role, hash token, dan metadata internal tidak diekspor.
     """
-    fieldnames = ["student_id", "token", "nama_siswa", *lesson_slugs]
+    headers_map = lesson_headers or {}
+    resolved_columns: list[tuple[str, str]] = []
+    for item in lesson_slugs:
+        header_label = headers_map.get(item, item)
+        canonical_slug = extract_slug_from_header(item)
+        resolved_columns.append((canonical_slug, header_label))
+
+    fieldnames = ["student_id", "token", "nama_siswa", *[lbl for _, lbl in resolved_columns]]
     out = io.StringIO()
     out.write(f"{LEGEND_COMMENT_LINE}\n")
     writer = csv.DictWriter(
@@ -371,7 +419,7 @@ def serialize_export_csv(
             "token": "",  # selalu kosong — tidak ada export/recovery token
             "nama_siswa": row.display_name,
         }
-        for slug in lesson_slugs:
-            record[slug] = format_roundtrip_cell(row.progress.get(slug))
+        for slug, col_name in resolved_columns:
+            record[col_name] = format_roundtrip_cell(row.progress.get(slug))
         writer.writerow(record)
     return out.getvalue().encode("utf-8-sig")
diff --git a/services/tests/test_repositories.py b/services/tests/test_repositories.py
index 774baaa..8594248 100644
--- a/services/tests/test_repositories.py
+++ b/services/tests/test_repositories.py
@@ -150,7 +150,7 @@ def test_export_csv_content_and_no_leak():
         assert csv_bytes.startswith("\ufeff".encode("utf-8"))
         lines = text.strip().splitlines()
         assert lines[0].startswith("# Format kolom lesson:")
-        assert lines[1] == "student_id;token;nama_siswa;hello_world;variabel"
+        assert lines[1] == "student_id;token;nama_siswa;hello_world [completed];variabel [completed]"
         assert len(lines) == 3  # hanya 1 siswa (teacher tidak ikut)
         cols = lines[2].split(";")
         assert cols[0] == s1.id
@@ -612,7 +612,7 @@ def test_roundtrip_export_restore_delete_recreate():
         text = csv_bytes.decode("utf-8-sig")
         lines = text.strip().splitlines()
         assert lines[0].startswith("# Format kolom lesson:")
-        assert lines[1] == "student_id;token;nama_siswa;hello_world;variabel"
+        assert lines[1] == "student_id;token;nama_siswa;hello_world [completed];variabel [completed]"
         cols = lines[2].split(";")
         assert cols[0] == s1.id and cols[1] == ""  # token kosong
         assert cols[2] == "Budi Santoso" and cols[3] == "completed" and cols[4] == "3/4"
diff --git a/services/tests/test_student_management_routes.py b/services/tests/test_student_management_routes.py
index 936334b..786ec9e 100644
--- a/services/tests/test_student_management_routes.py
+++ b/services/tests/test_student_management_routes.py
@@ -691,3 +691,98 @@ def test_add_student_empty_name_rejected(client):
     assert data["success"] is False
     assert resp.status_code == 400
 
+
+def test_export_modify_import_progress_sync_roundtrip(client):
+    """Verifikasi bahwa modifikasi progres di CSV (completed, skor, RESET)
+    tersinkronisasi ke model progres komposit dan terefleksi di /progress-report.json.
+    """
+    seeded = _seed_teacher_and_students()
+    _login_teacher(client)
+    s1, s2 = seeded["students"]
+
+    # 1) Export CSV awal
+    resp_export = client.post("/students/export-csv", json={"student_ids": [s1.id, s2.id]})
+    assert resp_export.status_code == 200
+
+    # 2) Ubah progres: s1 dapat 'completed' di hello_world, s2 dapat '3/4' di variabel
+    modified_rows = [
+        f"{s1.id};;{s1.display_name};completed;",
+        f"{s2.id};;{s2.display_name};;3/4",
+    ]
+    csv_content = _valid_csv(modified_rows)
+
+    # 3) Import CSV kembali
+    resp_import = _upload(client, "/students/import", csv_content)
+    assert resp_import.status_code == 200
+    assert resp_import.get_json()["success"] is True
+
+    # 4) Periksa /progress-report.json
+    resp_report = client.get("/progress-report.json")
+    assert resp_report.status_code == 200
+    assert "no-store" in resp_report.headers.get("Cache-Control", "")
+    data = resp_report.get_json()
+    students = {st["id"]: st for st in data["students"]}
+
+    # s1 hello_world harus punya composite 100 dan status completed
+    st1 = students[s1.id]
+    assert st1["hello_world_composite"] == 100
+    assert st1["hello_world"] == "completed"
+
+    # s2 variabel harus punya quiz_score '3/4' dan composite terhitung
+    st2 = students[s2.id]
+    assert st2["variabel_quiz_score"] == "3/4"
+    assert st2["variabel_composite"] is not None
+
+    # 5) Reset progres s1 via CSV 'RESET'
+    reset_rows = [
+        f"{s1.id};;{s1.display_name};RESET;",
+        f"{s2.id};;{s2.display_name};;3/4",
+    ]
+    resp_reset = _upload(client, "/students/import", _valid_csv(reset_rows))
+    assert resp_reset.status_code == 200
+
+    resp_report_after = client.get("/progress-report.json")
+    st1_after = next(s for s in resp_report_after.get_json()["students"] if s["id"] == s1.id)
+    assert st1_after["hello_world_composite"] is None
+
+
+def test_export_csv_headers_contain_expected_format_guide(client):
+    """Verifikasi bahwa file CSV yang diekspor memuat expected format di header kolom lesson
+    dan file tersebut dapat dimodifikasi serta diimpor kembali dengan sukses.
+    """
+    seeded = _seed_teacher_and_students()
+    _login_teacher(client)
+    s1, s2 = seeded["students"]
+
+    resp_export = client.post("/students/export-csv", json={"student_ids": [s1.id, s2.id]})
+    assert resp_export.status_code == 200
+
+    text = resp_export.data.decode("utf-8-sig")
+    lines = text.strip().splitlines()
+    assert lines[0].startswith("# Format kolom lesson:")
+    header_line = lines[1]
+    assert "hello_world [completed]" in header_line
+    assert "variabel [completed]" in header_line
+
+    # Modifikasi langsung baris CSV hasil export dengan format baru
+    # Pertahankan header asli berformat: student_id;token;nama_siswa;hello_world [completed];variabel [completed]
+    modified_csv = (
+        f"{lines[0]}\n"
+        f"{header_line}\n"
+        f"{s1.id};;{s1.display_name};completed;\n"
+        f"{s2.id};;{s2.display_name};;3/4\n"
+    ).encode("utf-8-sig")
+
+    resp_import = _upload(client, "/students/import", modified_csv)
+    assert resp_import.status_code == 200
+    assert resp_import.get_json()["success"] is True
+
+    resp_report = client.get("/progress-report.json")
+    assert resp_report.status_code == 200
+    data = resp_report.get_json()
+    students = {st["id"]: st for st in data["students"]}
+    assert students[s1.id]["hello_world_composite"] == 100
+    assert students[s2.id]["variabel_quiz_score"] == "3/4"
+
+
+
diff --git a/services/tests/test_student_roundtrip.py b/services/tests/test_student_roundtrip.py
index 4bb6a5b..06b6b49 100644
--- a/services/tests/test_student_roundtrip.py
+++ b/services/tests/test_student_roundtrip.py
@@ -27,6 +27,7 @@ from services.student_roundtrip import (
     StudentRoundTripRow,
     is_canonical_uuid,
     mask_student_id,
+    extract_slug_from_header,
     parse_roundtrip_csv,
     serialize_export_csv,
 )
@@ -699,3 +700,53 @@ def test_parse_roundtrip_csv_without_legend_row_backward_compatible():
         "done", exercise_passed=True, quiz_earned=3, quiz_total=6
     )
 
+
+def test_extract_slug_from_header_various_formats():
+    active = {"hello_world", "quiz_test", "c_loop"}
+    assert extract_slug_from_header("hello_world", active) == "hello_world"
+    assert extract_slug_from_header("hello_world [completed]", active) == "hello_world"
+    assert extract_slug_from_header("quiz_test [<earned>/4]", active) == "quiz_test"
+    assert extract_slug_from_header("quiz_test [<earned>/<total>]", active) == "quiz_test"
+    assert extract_slug_from_header("c_loop [done:<1|0>:<earned>/5]", active) == "c_loop"
+    assert extract_slug_from_header("Hello World (hello_world) [completed]", active) == "hello_world"
+    assert extract_slug_from_header("Hello World (hello_world)", active) == "hello_world"
+    assert extract_slug_from_header("unknown_col [completed]", active) == "unknown_col"
+
+
+def test_export_serializer_with_lesson_headers_mapping():
+    rows = _sample_export_rows()
+    lesson_headers = {
+        "hello_world": "hello_world [completed]",
+        "variabel": "variabel [<earned>/4]",
+    }
+    data = serialize_export_csv(rows, ["hello_world", "variabel"], lesson_headers=lesson_headers)
+    text = data.decode("utf-8-sig")
+    lines = text.strip().splitlines()
+    assert lines[1] == "student_id;token;nama_siswa;hello_world [completed];variabel [<earned>/4]"
+    assert lines[2].startswith(f"{UUID_1};;Nama Siswa 1;completed;3/4")
+
+
+def test_parse_roundtrip_csv_with_inline_format_headers():
+    content = (
+        f"{LEGEND_COMMENT_LINE}\n"
+        "student_id;token;nama_siswa;hello_world [completed];variabel [<earned>/4]\n"
+        f"{UUID_1};;Budi;completed;3/4\n"
+    )
+    rows = parse_roundtrip_csv(content, ["hello_world", "variabel"])
+    assert len(rows) == 1
+    assert rows[0].student_id == UUID_1
+    assert rows[0].progress["hello_world"] == ParsedProgress("completed")
+    assert rows[0].progress["variabel"] == ParsedProgress("scored", 3, 4)
+
+
+def test_parse_roundtrip_csv_error_with_inline_format_header_reports_column_name():
+    content = (
+        f"{LEGEND_COMMENT_LINE}\n"
+        "student_id;token;nama_siswa;hello_world [completed]\n"
+        f"{UUID_1};;Budi;invalid_format\n"
+    )
+    with pytest.raises(RoundTripImportError) as exc:
+        parse_roundtrip_csv(content, ["hello_world"])
+    assert "kolom hello_world [completed]" in "; ".join(exc.value.errors)
+
+