diff --git a/.gitignore b/.gitignore
index 28515d9..3e12100 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,4 @@
-/build/sdlamp2
-/build/sdlamp2.dSYM
+/build/
 *.mp3
 *.m4a
 positions.txt
diff --git a/CLAUDE.md b/CLAUDE.md
index 21d91a5..c5f25e8 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -24,7 +24,7 @@ No test suite, no linter, no Makefile/CMake.
 
 ## Architecture
 
-Single-file C program: `src/sdlamp2.c` (~650 lines). One generated header: `src/controls_png.h` (embedded PNG byte array — regenerate with `./tools/embed_png.py build/controls.png src/controls_png.h` if the spritesheet changes).
+Single-file C program: `src/sdlamp2.c` (~650 lines). One generated header: `src/controls_png.h` (embedded PNG byte array — regenerate with `./tools/embed_png.py assets/controls.png src/controls_png.h` if the spritesheet changes).
 
 Key sections in order:
 - **Decoder struct** — holds all FFmpeg state (format/codec contexts, swr resampler, album art texture)
diff --git a/build/controls.png b/assets/controls.png
similarity index 100%
rename from build/controls.png
rename to assets/controls.png
diff --git a/build/.keep b/build/.keep
deleted file mode 100644
index e69de29..0000000
diff --git a/build/music.wav b/build/music.wav
deleted file mode 100644
index 002f815..0000000
Binary files a/build/music.wav and /dev/null differ
diff --git a/tools/embed_png.py b/tools/embed_png.py
index 4ea26b6..fddd417 100755
--- a/tools/embed_png.py
+++ b/tools/embed_png.py
@@ -2,7 +2,7 @@
 #
 # embed_png.py — Convert a PNG file into a C header with a byte array.
 #
-# Usage: ./tools/embed_png.py build/controls.png src/controls_png.h
+# Usage: ./tools/embed_png.py assets/controls.png src/controls_png.h
 #
 
 import sys