diff --git a/offlineu_core.py b/offlineu_core.py
index 278bed2..7305fd3 100644
--- a/offlineu_core.py
+++ b/offlineu_core.py
@@ -526,25 +526,26 @@ def find_course_thumbnail(course_path: str) -> Optional[str]:
 
 
 _SECTION_NAME_RE = re.compile(
-    r'^(section|module|chapter|part|unit|lesson)\b', re.IGNORECASE
+    r'^(section|module|chapter|part|unit|lesson)\b|^\d+[\s_.\-]', re.IGNORECASE
 )
 
 
 def _looks_like_course(directory: Path) -> bool:
     """
-    Heuristic for 'this folder is a course, stop recursing into it':
-    it has media files directly, or at least two of its immediate
-    subfolders do (covers the common Section 1/, Section 2/... layout).
+    Heuristic for 'this folder is a course, stop recursing into it': it has
+    media files directly, or its media-holding immediate subfolders all
+    read as chapter/section labels ("Section 1", "Module 2", "01 -
+    Introduction", ...) rather than course titles - covers the common
+    Section 1/, Section 2/... (or numbered-chapter) layout.
 
-    Requiring 2+ matching subfolders (rather than just 1) avoids mistaking
-    a publisher/grouping folder that holds a single course - e.g.
-    Pluralsight/Docker Deep Dive/lesson.mp4 - for the course itself.
-
-    The one exception: a directory with exactly one media-holding subfolder
-    whose name reads as a section label ("Section 1", "Module 2", ...)
-    rather than a course title. That's still a course with just one
-    section, not a publisher folder - Pluralsight/Docker Deep Dive doesn't
-    get named "Section 1", so this doesn't reopen the ambiguity above.
+    Requiring *every* media-holding subfolder to match, not just one, is
+    what keeps a publisher/category folder holding several unrelated
+    courses - e.g. Claude/Pluralsight.X.../*.mp4 next to
+    Claude/Linkedin.Learning.Y.../*.mp4 - from being mistaken for a single
+    course just because more than one of its subfolders happens to store
+    episodes directly rather than nested under their own chapter folder.
+    Real course titles ("Pluralsight.Docker.Deep.Dive...") don't read as
+    chapter labels, so this doesn't reopen that ambiguity.
     """
     if _has_direct_media(directory):
         return True
@@ -556,14 +557,9 @@ def _looks_like_course(directory: Path) -> bool:
     except (PermissionError, OSError):
         return False
     children_with_media = [child for child in children if _has_direct_media(child)]
-    if len(children_with_media) >= 2:
-        return True
-    if (
-        len(children_with_media) == 1
-        and _SECTION_NAME_RE.match(children_with_media[0].name.strip())
-    ):
-        return True
-    return False
+    if not children_with_media:
+        return False
+    return all(_SECTION_NAME_RE.match(child.name.strip()) for child in children_with_media)
 
 
 HIDDEN_PATHS_FILE = os.path.join(DATA_DIR, 'hidden_paths.json')