Audio button clicks.
Nothing plays.
This is almost always one cause: the MP3 file wasn't copied into the deploy folder. Your HTML points to it but the server returns a 404.
Confirm it in 30 seconds
F12 → Network tab → click the audio button. You'll see an HTTP request for the MP3. If it returns 404, the file isn't on the server — that's your answer. If it returns 200 but still no sound, scroll down to the autoplay fix.
Common causes & fixes
The assets/ folder wasn't copied into _site/. Find your build script and add assets to the copy list.
Browser autoplay policy blocked it. Audio must be triggered by a direct user click — not a timer or page load event.
File exists in the repo but the build script doesn't copy it. Run the build locally and check ls _site/assets/audio/.
Check the src attribute — it must match the exact filename including case. PJ-Main.mp3 ≠ pj-main.mp3.
Add assets to your build script copy loop:
for dir in images css js public assets; do [ -d "$dir" ] && cp -r "$dir" _site/ done