From e4c811f51d669ec117f50b93307b0c5530b7569c Mon Sep 17 00:00:00 2001 From: jimmy Date: Fri, 1 May 2026 20:24:05 +1200 Subject: [PATCH] Expand browser editor runtime and LED simulation workflows. Add Docker deployment support, richer Selenium/LED pattern tests, in-browser diagnostics, responsive UI improvements, and 16x16 panel simulation tooling to speed iteration and hardware-style prototyping. Made-with: Cursor --- .cursor/hooks.json | 12 + .cursor/hooks/dev-reload-touch.sh | 8 + .dockerignore | 14 + Dockerfile | 19 ++ LED_TUTORIAL.md | 75 +++++ Pipfile | 1 + Pipfile.lock | 90 +++++- README.md | 61 ++++ docker-compose.yml | 16 + src/static/.reload-token | 1 + src/static/index.html | 29 +- src/static/pyodide-worker.js | 34 ++- src/static/script.js | 390 ++++++++++++++++++++++--- src/static/styles.css | 213 +++++++++++++- tests/test_led_patterns.py | 44 +++ tests/test_selenium_smoke.py | 24 ++ workspace/code/led_patterns.py | 67 +++++ workspace/code/led_tutorial.py | 50 ++++ workspace/code/neopixel_demo.py | 12 + workspace/code/neopixel_time_test.py | 32 ++ workspace/code/panel16_bounce.py | 41 +++ workspace/code/panel16_matrix_rain.py | 37 +++ workspace/code/panel16_rainbow_wave.py | 33 +++ workspace/code/panel16_utils.py | 26 ++ workspace/code/pattern_chase_demo.py | 20 ++ workspace/code/pattern_rainbow_demo.py | 20 ++ workspace/code/pattern_twinkle_demo.py | 26 ++ workspace/lib/led_patterns.py | 68 +++++ workspace/lib/machine.py | 19 ++ workspace/lib/neopixel.py | 56 ++++ 30 files changed, 1478 insertions(+), 60 deletions(-) create mode 100644 .cursor/hooks.json create mode 100755 .cursor/hooks/dev-reload-touch.sh create mode 100644 .dockerignore create mode 100644 Dockerfile create mode 100644 LED_TUTORIAL.md create mode 100644 docker-compose.yml create mode 100644 src/static/.reload-token create mode 100644 tests/test_led_patterns.py create mode 100644 workspace/code/led_patterns.py create mode 100644 workspace/code/led_tutorial.py create mode 100644 workspace/code/neopixel_demo.py create mode 100644 workspace/code/neopixel_time_test.py create mode 100644 workspace/code/panel16_bounce.py create mode 100644 workspace/code/panel16_matrix_rain.py create mode 100644 workspace/code/panel16_rainbow_wave.py create mode 100644 workspace/code/panel16_utils.py create mode 100644 workspace/code/pattern_chase_demo.py create mode 100644 workspace/code/pattern_rainbow_demo.py create mode 100644 workspace/code/pattern_twinkle_demo.py create mode 100644 workspace/lib/led_patterns.py create mode 100644 workspace/lib/machine.py create mode 100644 workspace/lib/neopixel.py diff --git a/.cursor/hooks.json b/.cursor/hooks.json new file mode 100644 index 0000000..8490b03 --- /dev/null +++ b/.cursor/hooks.json @@ -0,0 +1,12 @@ +{ + "version": 1, + "hooks": { + "afterFileEdit": [ + { + "command": ".cursor/hooks/dev-reload-touch.sh", + "timeout": 5, + "matcher": "Write|TabWrite" + } + ] + } +} diff --git a/.cursor/hooks/dev-reload-touch.sh b/.cursor/hooks/dev-reload-touch.sh new file mode 100755 index 0000000..39921ea --- /dev/null +++ b/.cursor/hooks/dev-reload-touch.sh @@ -0,0 +1,8 @@ +#!/usr/bin/env bash +set -euo pipefail + +# Consume hook JSON input (not needed for this hook). +cat >/dev/null || true + +mkdir -p "src/static" +date +%s%3N > "src/static/.reload-token" diff --git a/.dockerignore b/.dockerignore new file mode 100644 index 0000000..186d081 --- /dev/null +++ b/.dockerignore @@ -0,0 +1,14 @@ +.git +.gitignore +.venv +__pycache__/ +.pytest_cache/ +.mypy_cache/ +.ruff_cache/ +.cursor/ +tests/ +agent-transcripts/ +data/ +*.pyc +*.pyo +*.pyd diff --git a/Dockerfile b/Dockerfile new file mode 100644 index 0000000..4034e25 --- /dev/null +++ b/Dockerfile @@ -0,0 +1,19 @@ +FROM python:3.12-slim + +ENV PYTHONDONTWRITEBYTECODE=1 \ + PYTHONUNBUFFERED=1 \ + PIP_NO_CACHE_DIR=1 + +WORKDIR /app + +RUN pip install --no-cache-dir pipenv + +COPY Pipfile Pipfile.lock ./ +RUN pipenv install --system --deploy + +COPY src ./src +COPY workspace ./workspace + +EXPOSE 8080 + +CMD ["uvicorn", "app:app", "--app-dir", "src", "--host", "0.0.0.0", "--port", "8080"] diff --git a/LED_TUTORIAL.md b/LED_TUTORIAL.md new file mode 100644 index 0000000..ceaa526 --- /dev/null +++ b/LED_TUTORIAL.md @@ -0,0 +1,75 @@ +# Python LED Tutorial (NeoPixel Focus) + +This tutorial is for the browser editor's ESP32-style mocks: + +- `machine.Pin` +- `neopixel.NeoPixel` + +Use `workspace/code/led_tutorial.py` while reading this guide. + +## 1) Basic setup + +```python +from machine import Pin +import neopixel + +np = neopixel.NeoPixel(Pin(4), 12) +``` + +- `Pin(4)` means data pin 4 (matching common ESP32 examples). +- `12` is the number of LEDs in the strip/ring. +- `np` is your LED strip object. + +## 2) Set one LED color + +```python +np[0] = (255, 0, 0) # red +np.write() +``` + +- Colors are `(red, green, blue)` from `0` to `255`. +- Nothing updates visually until `np.write()`. + +## 3) Fill all LEDs + +```python +np.fill((0, 0, 255)) # all blue +np.write() +``` + +## 4) Clear LEDs (turn off) + +```python +np.fill((0, 0, 0)) +np.write() +``` + +## 5) Animate over time + +```python +import time + +for step in range(20): + np.fill((step * 10, 0, 255 - step * 10)) + np.write() + time.sleep(0.08) +``` + +`time.sleep(...)` controls animation speed. + +## 6) Moving pixel example + +```python +for i in range(len(np)): + np.fill((0, 0, 0)) + np[i] = (255, 120, 0) + np.write() + time.sleep(0.06) +``` + +## 7) Tips + +- Keep color values in `0..255`. +- Use helper functions for repeated color logic. +- Start with short loops, then increase frames once behavior looks good. +- If the simulator is closed, run your script again to show updates. diff --git a/Pipfile b/Pipfile index 48f870d..1ceb9d0 100644 --- a/Pipfile +++ b/Pipfile @@ -8,6 +8,7 @@ pytest = "*" pytest-cov = "*" httpx = "*" selenium = "*" +playwright = "*" [packages] fastapi = "*" diff --git a/Pipfile.lock b/Pipfile.lock index f7c0140..0ca5574 100644 --- a/Pipfile.lock +++ b/Pipfile.lock @@ -1,7 +1,7 @@ { "_meta": { "hash": { - "sha256": "f9de958b9982b3a30c107c2c02746aece031522dc429be84e4f9589c73404282" + "sha256": "ce177325185c5a9e04401b9368766f419921dfc5f9de934820507dae79998082" }, "pipfile-spec": 6, "requires": { @@ -586,6 +586,71 @@ "markers": "python_version >= '3.10'", "version": "==7.13.5" }, + "greenlet": { + "hashes": [ + "sha256:0ecec963079cd58cbd14723582384f11f166fd58883c15dcbfb342e0bc9b5846", + "sha256:0ed006e4b86c59de7467eb2601cd1b77b5a7d657d1ee55e30fe30d76451edba4", + "sha256:0ff251e9a0279522e62f6176412869395a64ddf2b5c5f782ff609a8216a4e662", + "sha256:1aa4ce8debcd4ea7fb2e150f3036588c41493d1d52c43538924ae1819003f4ce", + "sha256:1bae92a1dd94c5f9d9493c3a212dd874c202442047cf96446412c862feca83a2", + "sha256:1eb67d5adefb5bd2e182d42678a328979a209e4e82eb93575708185d31d1f588", + "sha256:2094acd54b272cb6eae8c03dd87b3fa1820a4cef18d6889c378d503500a1dc13", + "sha256:2628d6c86f6cb0cb45e0c3c54058bbec559f57eaae699447748cb3928150577e", + "sha256:29ea813b2e1f45fa9649a17853b2b5465c4072fbcb072e5af6cd3a288216574a", + "sha256:362624e6a8e5bca3b8233e45eef33903a100e9539a2b995c364d595dbc4018b3", + "sha256:3a717fbc46d8a354fa675f7c1e813485b6ba3885f9bef0cd56e5ba27d758ff5b", + "sha256:3bc59be3945ae9750b9e7d45067d01ae3fe90ea5f9ade99239dabdd6e28a5033", + "sha256:3ec9ea74e7268ace7f9aab1b1a4e730193fc661b39a993cd91c606c32d4a3628", + "sha256:41353ec2ecedf7aa8f682753a41919f8718031a6edac46b8d3dc7ed9e1ceb136", + "sha256:47422135b1d308c14b2c6e758beedb1acd33bb91679f5670edf77bf46244722b", + "sha256:4964101b8585c144cbda5532b1aa644255126c08a265dae90c16e7a0e63aaa9d", + "sha256:4a448128607be0de65342dc9b31be7f948ef4cc0bc8832069350abefd310a8f2", + "sha256:4b28037cb07768933c54d81bfe47a85f9f402f57d7d69743b991a713b63954eb", + "sha256:4d0eadc7e4d9ffb2af4247b606cae307be8e448911e5a0d0b16d72fc3d224cfd", + "sha256:54d243512da35485fc7a6bf3c178fdda6327a9d6506fcdd62b1abd1e41b2927b", + "sha256:55fa7ea52771be44af0de27d8b80c02cd18c2c3cddde6c847ecebdf72418b6a1", + "sha256:57a43c6079a89713522bc4bcb9f75070ecf5d3dbad7792bfe42239362cbf2a16", + "sha256:58c1c374fe2b3d852f9b6b11a7dff4c85404e51b9a596fd9e89cf904eb09866d", + "sha256:5a5ed18de6a0f6cc7087f1563f6bd93fc7df1c19165ca01e9bde5a5dc281d106", + "sha256:5e05ba267789ea87b5a155cf0e810b1ab88bf18e9e8740813945ceb8ee4350ba", + "sha256:5ecd83806b0f4c2f53b1018e0005cd82269ea01d42befc0368730028d850ed1c", + "sha256:64d6ac45f7271f48e45f67c95b54ef73534c52ec041fcda8edf520c6d811f4bc", + "sha256:680bd0e7ad5e8daa8a4aa89f68fd6adc834b8a8036dc256533f7e08f4a4b01f7", + "sha256:6c18dfb59c70f5a94acd271c72e90128c3c776e41e5f07767908c8c1b74ad339", + "sha256:6d874e79afd41a96e11ff4c5d0bc90a80973e476fda1c2c64985667397df432b", + "sha256:7022615368890680e67b9965d33f5773aade330d5343bbe25560135aaa849eae", + "sha256:703cb211b820dbffbbc55a16bfc6e4583a6e6e990f33a119d2cc8b83211119c8", + "sha256:728a73687e39ae9ca34e4694cbf2f049d3fbc7174639468d0f67200a97d8f9e2", + "sha256:728d9667d8f2f586644b748dbd9bb67e50d6a9381767d1357714ea6825bb3bf5", + "sha256:762612baf1161ccb8437c0161c668a688223cba28e1bf038f4eb47b13e39ccdf", + "sha256:7fc391b1566f2907d17aaebe78f8855dc45675159a775fcf9e61f8ee0078e87f", + "sha256:804a70b328e706b785c6ef16187051c394a63dd1a906d89be24b6ad77759f13f", + "sha256:83ed9f27f1680b50e89f40f6df348a290ea234b249a4003d366663a12eab94f2", + "sha256:884f649de075b84739713d41dd4dfd41e2b910bfb769c4a3ea02ec1da52cd9bb", + "sha256:8f1cc966c126639cd152fdaa52624d2655f492faa79e013fea161de3e6dda082", + "sha256:8f52a464e4ed91780bdfbbdd2b97197f3accaa629b98c200f4dffada759f3ae7", + "sha256:9c615f869163e14bb1ced20322d8038fb680b08236521ac3f30cd4c1288785a0", + "sha256:9d280a7f5c331622c69f97eb167f33577ff2d1df282c41cd15907fc0a3ca198c", + "sha256:a10a732421ab4fec934783ce3e54763470d0181db6e3468f9103a275c3ed1853", + "sha256:a96fcee45e03fe30a62669fd16ab5c9d3c172660d3085605cb1e2d1280d3c988", + "sha256:a97e4821aa710603f94de0da25f25096454d78ffdace5dc77f3a006bc01abba3", + "sha256:ba8f0bdc2fae6ce915dfd0c16d2d00bca7e4247c1eae4416e06430e522137858", + "sha256:bf2d8a80bec89ab46221ae45c5373d5ba0bd36c19aa8508e85c6cd7e5106cd37", + "sha256:cda05425526240807408156b6960a17a79a0c760b813573b67027823be760977", + "sha256:d419647372241bc68e957bf38d5c1f98852155e4146bd1e4121adea81f4f01e4", + "sha256:d4d9f0624c775f2dfc56ba54d515a8c771044346852a918b405914f6b19d7fd8", + "sha256:d60097128cb0a1cab9ea541186ea13cd7b847b8449a7787c2e2350da0cb82d86", + "sha256:db2910d3c809444e0a20147361f343fe2798e106af8d9d8506f5305302655a9f", + "sha256:ddb36c7d6c9c0a65f18c7258634e0c416c6ab59caac8c987b96f80c2ebda0112", + "sha256:ddc090c5c1792b10246a78e8c2163ebbe04cf877f9d785c230a7b27b39ad038e", + "sha256:e5ddf316ced87539144621453c3aef229575825fe60c604e62bedc4003f372b2", + "sha256:f35807464c4c58c55f0d31dfa83c541a5615d825c2fe3d2b95360cf7c4e3c0a8", + "sha256:f8c30c2225f40dd76c50790f0eb3b5c7c18431efb299e2782083e1981feed243", + "sha256:fa94cb2288681e3a11645958f1871d48ee9211bd2f66628fdace505927d6e564" + ], + "markers": "platform_machine == 'aarch64' or (platform_machine == 'ppc64le' or (platform_machine == 'x86_64' or (platform_machine == 'amd64' or (platform_machine == 'AMD64' or (platform_machine == 'win32' or platform_machine == 'WIN32')))))", + "version": "==3.5.0" + }, "h11": { "hashes": [ "sha256:4e35b956cf45792e4caa5885e69fba00bdbc6ffafbfa020300e549b208ee5ff1", @@ -643,6 +708,21 @@ "markers": "python_version >= '3.8'", "version": "==26.2" }, + "playwright": { + "hashes": [ + "sha256:4a4a2d4842b0e4120de3fa48636e4b69085a05b81d8a35ad4353f530ade72ed6", + "sha256:6989c476be2b9cd3e24a18cc9dcf202e266fb3d91e3e5395cd668c54ea54b119", + "sha256:8c881a19377d2b900af855fb525b5f22a27bf3cfbecba6d1edb36766d56cb100", + "sha256:93581ad515728cadc8af39b288a5633ba6d36e7d72048e79d890ce01ea2156f9", + "sha256:af068143a0c045ec11608b67d6c42e58db7e9cf65a742dd21fddedc1a9802c47", + "sha256:bfc6940100b57423175c819ce2422ec5880d55fa2769987f62ab7a1f5fe6783e", + "sha256:c5792aad9e22b91a09264b9edbc18553cf05ea5a39404d65dc19a012c6b2e51d", + "sha256:d5a5cc064b82ca92996080025710844e417f44df8fda9001102c28f44174171c" + ], + "index": "pypi", + "markers": "python_version >= '3.9'", + "version": "==1.59.0" + }, "pluggy": { "hashes": [ "sha256:7dcc130b76258d33b90f61b658791dede3486c3e6bfb003ee5c9bfb396dd22f3", @@ -651,6 +731,14 @@ "markers": "python_version >= '3.9'", "version": "==1.6.0" }, + "pyee": { + "hashes": [ + "sha256:0b931f7c14535667ed4c7e0d531716368715e860b988770fc7eb8578d1f67fc8", + "sha256:af2f8fede4171ef667dfded53f96e2ed0d6e6bd7ee3bb46437f77e3b57689228" + ], + "markers": "python_version >= '3.8'", + "version": "==13.0.1" + }, "pygments": { "hashes": [ "sha256:6757cd03768053ff99f3039c1a36d6c0aa0b263438fcab17520b30a303a82b5f", diff --git a/README.md b/README.md index ed483b7..d7ce749 100644 --- a/README.md +++ b/README.md @@ -48,6 +48,24 @@ If nothing is listening, the smoke test **skips** with a short message instead o Open [http://localhost:8080](http://localhost:8080). +## Deploy with Docker + +Build and run with Docker Compose: + +```bash +cp .env.example .env +mkdir -p data +docker compose up --build +``` + +Then open [http://localhost:8080](http://localhost:8080). + +Notes: + +- `workspace/` is mounted to `/app/workspace` so your code persists locally. +- `data/` is mounted to `/app/data` for the SQLite auth DB. +- In container mode, `WORKSPACE_ROOT` and `AUTH_DATABASE_PATH` are set by `docker-compose.yml`. + **User accounts** — Set `AUTH_ENABLED=true` in `.env` to require sign-in for workspace APIs. Users live in a SQLite file (`AUTH_DATABASE_PATH`, default `./data/editor.db`). Use `/register` (if `AUTH_REGISTER_OPEN=true`) or `BOOTSTRAP_ADMIN_USERNAME` / `BOOTSTRAP_ADMIN_PASSWORD` for the first superuser. Superusers can **GET/POST/DELETE `/api/users`** to list, create, or remove accounts. **API key** — If `EDITOR_API_KEY` is set, requests may use `Authorization: Bearer …` instead of a session (useful for automation). When `AUTH_ENABLED=true`, a valid session *or* API key is accepted. @@ -58,3 +76,46 @@ The home page can store the API key in `sessionStorage` when you are not using c - `src/` — FastAPI app and static UI (`src/static/`) - `workspace/` — default tree: `code/` (editable), `lib/` (read-only via API) + +## ESP32 / NeoPixel mock + +The browser runtime now includes MicroPython-style mocks in `workspace/lib`: + +- `machine.Pin` +- `neopixel.NeoPixel` + +Use them from scripts in `workspace/code` exactly like ESP32 examples: + +```python +from machine import Pin +import neopixel + +np = neopixel.NeoPixel(Pin(4), 8) +np[0] = (255, 0, 0) +np.write() +``` + +`write()` updates the NeoPixel simulator window so you can verify behavior visually. + +Tutorial files: + +- `LED_TUTORIAL.md` - step-by-step NeoPixel tutorial +- `workspace/code/led_tutorial.py` - runnable guided LED example +- `workspace/code/led_patterns.py` - reusable pattern helpers (`rainbow_frame`, `chase_frame`, `twinkle_frame`) +- `workspace/code/pattern_rainbow_demo.py` - rainbow animation demo +- `workspace/code/pattern_chase_demo.py` - chase animation demo +- `workspace/code/pattern_twinkle_demo.py` - twinkle animation demo +- `workspace/code/panel16_utils.py` - helpers for 16x16 serpentine mapping +- `workspace/code/panel16_rainbow_wave.py` - 16x16 rainbow wave +- `workspace/code/panel16_bounce.py` - 16x16 bouncing pixel with trail +- `workspace/code/panel16_matrix_rain.py` - 16x16 matrix rain effect + +## Dev auto-reload hook + +Project hook files are included in `.cursor/`: + +- `.cursor/hooks.json` +- `.cursor/hooks/dev-reload-touch.sh` + +When files are edited through Cursor tools, the hook updates `src/static/.reload-token`. +The editor (on localhost) polls that token and auto-reloads the browser when it changes. diff --git a/docker-compose.yml b/docker-compose.yml new file mode 100644 index 0000000..ba85a63 --- /dev/null +++ b/docker-compose.yml @@ -0,0 +1,16 @@ +services: + python-editor: + build: + context: . + dockerfile: Dockerfile + ports: + - "8080:8080" + env_file: + - .env + environment: + - WORKSPACE_ROOT=/app/workspace + - AUTH_DATABASE_PATH=/app/data/editor.db + volumes: + - ./workspace:/app/workspace + - ./data:/app/data + restart: unless-stopped diff --git a/src/static/.reload-token b/src/static/.reload-token new file mode 100644 index 0000000..75786fb --- /dev/null +++ b/src/static/.reload-token @@ -0,0 +1 @@ +1777623664358 diff --git a/src/static/index.html b/src/static/index.html index 564fbcc..387b880 100644 --- a/src/static/index.html +++ b/src/static/index.html @@ -5,7 +5,7 @@ Python Editor - +
@@ -29,6 +29,7 @@
Browser · Pyodide + LSP: n/a
Home @@ -36,9 +37,14 @@
- + +
@@ -49,6 +55,19 @@
+ +
Console Output

@@ -67,6 +86,6 @@
     

   
 
-  
+  
 
 
diff --git a/src/static/pyodide-worker.js b/src/static/pyodide-worker.js
index 5d36e34..4300ea8 100644
--- a/src/static/pyodide-worker.js
+++ b/src/static/pyodide-worker.js
@@ -77,6 +77,38 @@ json.dumps(out)
       return;
     }
 
+    if (type === 'diagnostics') {
+      const rel = String(payload.path || 'scratch.py').replace(/^\/+/, '');
+      const vpath = `/workspace/${rel}`;
+      p.globals.set('__diag_code', String(payload.content ?? ''));
+      p.globals.set('__diag_path', vpath);
+      p.globals.set('__diag_extra_json', JSON.stringify(payload.extra_files || {}));
+      const raw = p.runPython(`
+import json, os
+import jedi
+
+extra = json.loads(__diag_extra_json)
+os.makedirs("/workspace", exist_ok=True)
+for rel_path, body in extra.items():
+    rel_path = str(rel_path).lstrip("/")
+    full = os.path.join("/workspace", rel_path)
+    os.makedirs(os.path.dirname(full), exist_ok=True)
+    with open(full, "w", encoding="utf-8") as fh:
+        fh.write(str(body))
+os.makedirs(os.path.dirname(__diag_path), exist_ok=True)
+with open(__diag_path, "w", encoding="utf-8") as fh:
+    fh.write(__diag_code)
+proj = jedi.Project("/workspace")
+s = jedi.Script(code=__diag_code, path=__diag_path, project=proj)
+errs = s.get_syntax_errors()
+out = [{"line": e.line, "column": e.column, "message": str(e.get_message())} for e in errs]
+json.dumps(out)
+`);
+      const diagnostics = JSON.parse(String(raw));
+      self.postMessage({ id, type: 'diagnostics', ok: true, diagnostics });
+      return;
+    }
+
     if (type === 'run') {
       const files = payload.files && typeof payload.files === 'object' ? payload.files : {};
       const mainRel = String(payload.mainPath || '').replace(/^\/+/, '');
@@ -97,7 +129,7 @@ for rel, body in files.items():
     with open(full, "w", encoding="utf-8") as fh:
         fh.write(str(body))
 
-for entry in ("/workspace/lib", "/workspace"):
+for entry in ("/workspace/code", "/workspace/lib", "/workspace"):
     if entry not in sys.path:
         sys.path.insert(0, entry)
 
diff --git a/src/static/script.js b/src/static/script.js
index 3c95c96..fc93e2e 100644
--- a/src/static/script.js
+++ b/src/static/script.js
@@ -1,4 +1,6 @@
-import { EditorView, basicSetup } from "/static/codemirror.bundle.mjs";
+import { EditorView, basicSetup } from "https://esm.sh/codemirror";
+import { Compartment } from "https://esm.sh/@codemirror/state";
+import { python } from "https://esm.sh/@codemirror/lang-python";
 
 class TextEditor {
   constructor() {
@@ -7,6 +9,7 @@ class TextEditor {
     this.pyWorkerMsgId = 0;
     this.pyWorkerHandlers = new Map();
     this.pyodideInited = false;
+    this.workerWarmupPromise = null;
     this.pyRunGeneration = 0;
     this.editor = null;
     this.currentFilePath = null;
@@ -26,11 +29,19 @@ class TextEditor {
     this.completionIndex = 0;
     this.completionOpen = false;
     this.completionRequestId = 0;
+    this.diagnosticsRequestId = 0;
+    this.diagnosticsTimer = null;
     this.draggedItemPath = null;
     this.draggedItemIsDirectory = false;
     this.dragHoverExpandTimer = null;
     this.dragHoverTargetPath = null;
     this.savedSession = null;
+    this.languageCompartment = new Compartment();
+    this.autoCompleteTimer = null;
+    this.ledSimWindow = null;
+    this.ledPanelDismissed = false;
+    this.lastLedFrame = null;
+    this.ledPanelWindow = null;
 
     this.init();
   }
@@ -47,10 +58,44 @@ class TextEditor {
     this.loadSessionState();
     this.setupEditor();
     this.setupEventListeners();
+    this.setupDevAutoReload();
     this.updateRunButtonState();
+    this.setLspStatus('LSP: n/a', 'Open a Python file for diagnostics');
+    this.prewarmPyWorker();
     this.loadInitialDirectoryState().then(() => this.restoreSessionTabs());
   }
 
+  setupDevAutoReload() {
+    const isLocalhost =
+      window.location.hostname === 'localhost' ||
+      window.location.hostname === '127.0.0.1';
+    if (!isLocalhost) return;
+
+    let lastToken = null;
+    const poll = async () => {
+      try {
+        const resp = await fetch(`/static/.reload-token?ts=${Date.now()}`, { cache: 'no-store' });
+        if (!resp.ok) {
+          return;
+        }
+        const token = (await resp.text()).trim();
+        if (lastToken === null) {
+          lastToken = token;
+          return;
+        }
+        if (token && token !== lastToken) {
+          window.location.reload();
+          return;
+        }
+      } catch (_err) {
+        // Dev hook file may not exist yet.
+      }
+    };
+
+    setInterval(poll, 1000);
+    poll();
+  }
+
   apiFetch(url, init = {}) {
     const next = { ...init };
     const headers = new Headers(init.headers || {});
@@ -77,7 +122,7 @@ class TextEditor {
 
   ensurePyWorker() {
     if (!this.pyWorker) {
-      const worker = new Worker('/static/pyodide-worker.js');
+      const worker = new Worker('/static/pyodide-worker.js?v=3');
       this.pyWorker = worker;
       worker.onmessage = (event) => this.handlePyWorkerMessage(event);
     }
@@ -126,6 +171,19 @@ class TextEditor {
     this.pyodideInited = true;
   }
 
+  prewarmPyWorker() {
+    if (this.pyodideInited || this.workerWarmupPromise) {
+      return;
+    }
+    this.workerWarmupPromise = this.ensurePyodideReady()
+      .catch(() => {
+        // Ignore warm-up failures; next foreground run will retry.
+      })
+      .finally(() => {
+        this.workerWarmupPromise = null;
+      });
+  }
+
   loadSessionState() {
     try {
       const raw = localStorage.getItem(this.sessionStorageKey);
@@ -139,11 +197,13 @@ class TextEditor {
 
   saveSessionState() {
     try {
-      const runFileSelect = document.getElementById('run-file-select');
+      const runMainCheckbox = document.getElementById('run-main-checkbox');
+      const panelModeCheckbox = document.getElementById('panel-16x16-checkbox');
       const session = {
         openTabPaths: this.openTabs.map((tab) => tab.path),
         activeTabPath: this.activeTabPath,
-        selectedRunFile: runFileSelect ? runFileSelect.value : '',
+        runMainChecked: Boolean(runMainCheckbox && runMainCheckbox.checked),
+        panel16x16Checked: Boolean(panelModeCheckbox && panelModeCheckbox.checked),
         expandedDirs: Array.from(this.expandedDirs || []),
         selectedPath: this.selectedPath || '',
         selectedIsDirectory: Boolean(this.selectedIsDirectory)
@@ -170,9 +230,13 @@ class TextEditor {
     if (session.activeTabPath && this.findTab(session.activeTabPath)) {
       this.switchToTab(session.activeTabPath);
     }
-    const runFileSelect = document.getElementById('run-file-select');
-    if (runFileSelect && typeof session.selectedRunFile === 'string') {
-      runFileSelect.value = session.selectedRunFile;
+    const runMainCheckbox = document.getElementById('run-main-checkbox');
+    if (runMainCheckbox && typeof session.runMainChecked === 'boolean') {
+      runMainCheckbox.checked = session.runMainChecked;
+    }
+    const panelModeCheckbox = document.getElementById('panel-16x16-checkbox');
+    if (panelModeCheckbox && typeof session.panel16x16Checked === 'boolean') {
+      panelModeCheckbox.checked = session.panel16x16Checked;
     }
     this.saveSessionState();
   }
@@ -256,7 +320,7 @@ class TextEditor {
   setupEditor() {
     this.editor = new EditorView({
       doc: '',
-      extensions: [basicSetup],
+      extensions: [basicSetup, this.languageCompartment.of([])],
       parent: document.getElementById('editor')
     });
 
@@ -323,10 +387,88 @@ class TextEditor {
         this.hideCompletionDropdown();
         this.updateActiveTabContent();
         this.markAsModified();
+        this.scheduleAutoCompletion();
+        this.scheduleDiagnostics();
       }
     })(this.editor.dispatch);
   }
 
+  setLspStatus(text, title = '') {
+    const status = document.getElementById('lsp-status');
+    if (!status) return;
+    status.textContent = text;
+    status.title = title || text;
+  }
+
+  scheduleDiagnostics() {
+    if (this.diagnosticsTimer) {
+      clearTimeout(this.diagnosticsTimer);
+    }
+    this.diagnosticsTimer = setTimeout(() => {
+      this.runDiagnostics();
+    }, 220);
+  }
+
+  async runDiagnostics() {
+    if (!this.currentFilePath || !this.currentFilePath.toLowerCase().endsWith('.py')) {
+      this.setLspStatus('LSP: n/a', 'Open a Python file for diagnostics');
+      return;
+    }
+    const requestId = ++this.diagnosticsRequestId;
+    this.setLspStatus('LSP: checking...', 'Running Jedi syntax diagnostics');
+    try {
+      await this.ensurePyodideReady();
+      const extraFiles = {};
+      for (const tab of this.openTabs) {
+        if (tab.path && tab.path.toLowerCase().endsWith('.py')) {
+          extraFiles[tab.path] = tab.content;
+        }
+      }
+      const data = await this.callPyWorker('diagnostics', {
+        path: this.currentFilePath,
+        content: this.editor.state.doc.toString(),
+        extra_files: extraFiles
+      });
+      if (requestId !== this.diagnosticsRequestId) return;
+      const diagnostics = Array.isArray(data.diagnostics) ? data.diagnostics : [];
+      if (diagnostics.length === 0) {
+        this.setLspStatus('LSP: OK', 'No syntax errors');
+      } else {
+        const first = diagnostics[0];
+        const msg = `${first.message || 'Syntax error'} (line ${first.line ?? '?'})`;
+        this.setLspStatus(`LSP: ${diagnostics.length} issue(s)`, msg);
+      }
+    } catch (_error) {
+      this.setLspStatus('LSP: unavailable', 'Diagnostics failed');
+    }
+  }
+
+  scheduleAutoCompletion() {
+    if (!this.currentFilePath || !this.currentFilePath.toLowerCase().endsWith('.py')) {
+      return;
+    }
+    const cursor = this.editor.state.selection.main.head;
+    const doc = this.editor.state.doc.toString();
+    const prev = cursor > 0 ? doc[cursor - 1] : '';
+    if (!(prev === '.' || /[A-Za-z0-9_]/.test(prev))) {
+      return;
+    }
+    if (this.autoCompleteTimer) {
+      clearTimeout(this.autoCompleteTimer);
+    }
+    this.autoCompleteTimer = setTimeout(() => {
+      this.showCompletionDropdown();
+    }, 140);
+  }
+
+  setLanguageForPath(path) {
+    const ext = (path || '').toLowerCase();
+    const language = ext.endsWith('.py') ? python() : [];
+    this.editor.dispatch({
+      effects: this.languageCompartment.reconfigure(language),
+    });
+  }
+
   getCursorLineAndColumn() {
     const cursor = this.editor.state.selection.main.head;
     const lineInfo = this.editor.state.doc.lineAt(cursor);
@@ -566,6 +708,27 @@ class TextEditor {
       this.stopPython();
     });
 
+    const ledRunBtn = document.getElementById('led-run-btn');
+    if (ledRunBtn) {
+      ledRunBtn.addEventListener('click', () => {
+        this.runPython();
+      });
+    }
+    const ledStopBtn = document.getElementById('led-stop-btn');
+    if (ledStopBtn) {
+      ledStopBtn.addEventListener('click', () => {
+        this.stopPython();
+      });
+    }
+    const ledCloseBtn = document.getElementById('led-close-btn');
+    if (ledCloseBtn) {
+      ledCloseBtn.addEventListener('click', () => {
+        this.ledPanelDismissed = true;
+        const panel = document.getElementById('led-sim-panel');
+        if (panel) panel.classList.add('hidden');
+      });
+    }
+
     document.getElementById('create-file-btn').addEventListener('click', () => {
       this.createNewFile();
     });
@@ -590,15 +753,26 @@ class TextEditor {
       window.location.href = '/';
     });
 
-    document.getElementById('run-file-select').addEventListener('change', (event) => {
-      const selectedPath = event.target.value;
-      if (!selectedPath) return;
-      const tab = this.findTab(selectedPath);
-      if (tab) {
-        this.switchToTab(selectedPath);
-      }
-      this.saveSessionState();
-    });
+    const runMainCheckbox = document.getElementById('run-main-checkbox');
+    if (runMainCheckbox) {
+      runMainCheckbox.addEventListener('change', () => {
+        this.saveSessionState();
+        this.updateRunButtonState();
+      });
+    }
+    const panelModeCheckbox = document.getElementById('panel-16x16-checkbox');
+    if (panelModeCheckbox) {
+      panelModeCheckbox.addEventListener('change', () => {
+        this.saveSessionState();
+        if (!panelModeCheckbox.checked && this.ledPanelWindow && !this.ledPanelWindow.closed) {
+          this.ledPanelWindow.close();
+          this.ledPanelWindow = null;
+        }
+        if (this.lastLedFrame) {
+          this.renderLedSimulation(this.lastLedFrame);
+        }
+      });
+    }
 
   }
 
@@ -644,29 +818,9 @@ class TextEditor {
         this.closeTab(closeButton.dataset.path);
       });
     });
-    this.renderRunFileSelect();
     this.saveSessionState();
   }
 
-  renderRunFileSelect() {
-    const select = document.getElementById('run-file-select');
-    if (!select) return;
-    const pythonTabs = this.openTabs
-      .map((tab) => tab.path)
-      .filter((path) => typeof path === 'string' && path.toLowerCase().endsWith('.py'));
-    const currentValue = select.value;
-    select.innerHTML = '';
-    pythonTabs.forEach((path) => {
-      const option = document.createElement('option');
-      option.value = path;
-      option.textContent = path.startsWith('code/') ? path.slice('code/'.length) : path;
-      if (path === currentValue || path === this.currentFilePath) {
-        option.selected = true;
-      }
-      select.appendChild(option);
-    });
-  }
-
   findTab(path) {
     return this.openTabs.find((tab) => tab.path === path);
   }
@@ -705,10 +859,12 @@ class TextEditor {
       }
     });
     this.ignoreNextChange = false;
+    this.setLanguageForPath(path);
     const currentFileEl = document.getElementById('current-file');
     if (currentFileEl) currentFileEl.textContent = path;
     this.setEditorReadOnly(this.isReadOnlyPath(path));
     this.updateRunButtonState();
+    this.scheduleDiagnostics();
     if (tab.isModified) {
       this.markAsModified();
     } else {
@@ -737,6 +893,7 @@ class TextEditor {
         this.activeTabPath = null;
         this.currentFilePath = null;
         this.setEditorReadOnly(false);
+        this.setLanguageForPath('');
         this.ignoreNextChange = true;
         this.editor.dispatch({
           changes: {
@@ -749,6 +906,7 @@ class TextEditor {
         const currentFileEl = document.getElementById('current-file');
         if (currentFileEl) currentFileEl.textContent = 'No file selected';
         this.updateRunButtonState();
+        this.setLspStatus('LSP: n/a', 'Open a Python file for diagnostics');
         this.markAsSaved();
       }
     }
@@ -1021,12 +1179,14 @@ class TextEditor {
         }
       });
       this.ignoreNextChange = false;
+      this.setLanguageForPath(filePath);
       this.markAsSaved();
       this.setEditorReadOnly(this.isReadOnlyPath(filePath));
 
       const currentFileEl = document.getElementById('current-file');
       if (currentFileEl) currentFileEl.textContent = filePath;
       this.updateRunButtonState();
+      this.scheduleDiagnostics();
       this.renderTabs();
       this.saveSessionState();
     } catch (error) {
@@ -1107,6 +1267,7 @@ class TextEditor {
         const currentFileEl = document.getElementById('current-file');
         if (currentFileEl) currentFileEl.textContent = 'No file selected';
         this.updateRunButtonState();
+        this.setLspStatus('LSP: n/a', 'Open a Python file for diagnostics');
       }
 
       this.directoryCache.clear();
@@ -1129,6 +1290,7 @@ class TextEditor {
       } else {
         this.activeTabPath = null;
         this.currentFilePath = null;
+        this.setLanguageForPath('');
         this.ignoreNextChange = true;
         this.editor.dispatch({
           changes: {
@@ -1150,9 +1312,13 @@ class TextEditor {
   updateRunButtonState() {
     const runButton = document.getElementById('run-btn');
     const stopButton = document.getElementById('stop-btn');
+    const runMainCheckbox = document.getElementById('run-main-checkbox');
+    const runMainSelected = Boolean(runMainCheckbox && runMainCheckbox.checked);
     const hasPythonFile = Boolean(this.currentFilePath && this.currentFilePath.toLowerCase().endsWith('.py'));
-    runButton.disabled = !hasPythonFile || this.isPythonRunning;
+    const canRun = runMainSelected || hasPythonFile;
+    runButton.disabled = !canRun;
     stopButton.disabled = !this.isPythonRunning;
+    this.updateLedWindowControls();
   }
 
   clearConsole() {
@@ -1165,9 +1331,147 @@ class TextEditor {
     }
   }
 
+  maybePrepareLedWindow(files) {
+    const importsNeoPixel = Object.values(files || {}).some((content) =>
+      typeof content === 'string' &&
+      /\bimport\s+neopixel\b|\bfrom\s+neopixel\s+import\b/.test(content)
+    );
+    if (!importsNeoPixel) return;
+    this.ledPanelDismissed = false;
+    this.ensureLedWindow();
+  }
+
+  ensureLedWindow() {
+    const panel = document.getElementById('led-sim-panel');
+    if (!panel) return null;
+    if (!this.ledPanelDismissed) {
+      panel.classList.remove('hidden');
+    }
+    this.updateLedWindowControls();
+    return panel;
+  }
+
+  ensureLedPanelWindow() {
+    if (this.ledPanelWindow && !this.ledPanelWindow.closed) {
+      return this.ledPanelWindow;
+    }
+    const win = window.open('', 'neopixel-16x16', 'width=760,height=760');
+    if (!win) return null;
+    win.document.title = 'NeoPixel 16x16 Panel';
+    win.document.body.innerHTML = `
+      
+      
Waiting for frame...

+      

+    `;
+    this.ledPanelWindow = win;
+    return win;
+  }
+
+  closeLedPanelWindow() {
+    if (this.ledPanelWindow && !this.ledPanelWindow.closed) {
+      this.ledPanelWindow.close();
+    }
+    this.ledPanelWindow = null;
+  }
+
+  updateLedWindowControls() {
+    const runBtn = document.getElementById('led-run-btn');
+    const stopBtn = document.getElementById('led-stop-btn');
+    if (!runBtn || !stopBtn) return;
+    const runMainCheckbox = document.getElementById('run-main-checkbox');
+    const runMainSelected = Boolean(runMainCheckbox && runMainCheckbox.checked);
+    const hasPythonFile = Boolean(this.currentFilePath && this.currentFilePath.toLowerCase().endsWith('.py'));
+    runBtn.disabled = !(runMainSelected || hasPythonFile);
+    stopBtn.disabled = !this.isPythonRunning;
+  }
+
+  renderLedSimulation(frame) {
+    this.lastLedFrame = frame;
+    this.ledPanelDismissed = false;
+    if (!frame) return;
+    const panelModeCheckbox = document.getElementById('panel-16x16-checkbox');
+    const panelMode = Boolean(panelModeCheckbox && panelModeCheckbox.checked);
+    const pixels = Array.isArray(frame.pixels) ? frame.pixels : [];
+    if (panelMode) {
+      const panelWindow = this.ensureLedPanelWindow();
+      if (!panelWindow || panelWindow.closed) return;
+      const meta = panelWindow.document.getElementById('meta');
+      const grid = panelWindow.document.getElementById('grid');
+      if (!meta || !grid) return;
+      meta.textContent = `pin=${frame.pin ?? '?'} | leds=${pixels.length} | bpp=${frame.bpp ?? 3} | mode=16x16`;
+      grid.innerHTML = '';
+      const panelSize = 16 * 16;
+      for (let panelIndex = 0; panelIndex < panelSize; panelIndex += 1) {
+        const row = Math.floor(panelIndex / 16);
+        const col = panelIndex % 16;
+        const ledIndex = row % 2 === 0 ? row * 16 + (15 - col) : row * 16 + col;
+        const px = pixels[ledIndex] || [0, 0, 0];
+        const r = Number(px?.[0] ?? 0);
+        const g = Number(px?.[1] ?? 0);
+        const b = Number(px?.[2] ?? 0);
+        const div = panelWindow.document.createElement('div');
+        div.className = 'led';
+        div.title = `panel(${row},${col}) -> #${ledIndex} (${r}, ${g}, ${b})`;
+        div.style.backgroundColor = `rgb(${r}, ${g}, ${b})`;
+        div.style.boxShadow = `0 0 10px rgba(${r}, ${g}, ${b}, 0.55), inset 0 0 8px rgba(0,0,0,0.45)`;
+        grid.appendChild(div);
+      }
+    } else {
+      const panel = this.ensureLedWindow();
+      if (!panel) return;
+      const meta = document.getElementById('led-meta');
+      const grid = document.getElementById('led-grid');
+      if (!meta || !grid) return;
+      meta.textContent = `pin=${frame.pin ?? '?'} | leds=${pixels.length} | bpp=${frame.bpp ?? 3}`;
+      grid.innerHTML = '';
+      grid.classList.remove('panel-mode');
+      pixels.forEach((px, i) => {
+        const r = Number(px?.[0] ?? 0);
+        const g = Number(px?.[1] ?? 0);
+        const b = Number(px?.[2] ?? 0);
+        const div = document.createElement('div');
+        div.className = 'led';
+        div.title = `#${i} (${r}, ${g}, ${b})`;
+        div.style.backgroundColor = `rgb(${r}, ${g}, ${b})`;
+        div.style.boxShadow = `0 0 10px rgba(${r}, ${g}, ${b}, 0.55), inset 0 0 8px rgba(0,0,0,0.45)`;
+        grid.appendChild(div);
+      });
+    }
+  }
+
+  processSimulationLines(lines) {
+    for (const line of lines || []) {
+      if (typeof line !== 'string') continue;
+      const marker = '[neopixel-json]';
+      const idx = line.indexOf(marker);
+      if (idx === -1) continue;
+      const jsonPart = line.slice(idx + marker.length).trim();
+      if (!jsonPart) continue;
+      try {
+        const payload = JSON.parse(jsonPart);
+        if (payload && payload.type === 'neopixel') {
+          this.renderLedSimulation(payload);
+        }
+      } catch (_err) {
+        // Ignore malformed simulation payloads.
+      }
+    }
+  }
+
   appendConsoleOutput(lines) {
     if (!Array.isArray(lines) || lines.length === 0) return;
-    this.consolePendingText += lines.join('');
+    this.processSimulationLines(lines);
+    const visibleLines = lines.filter((line) => {
+      if (typeof line !== 'string') return false;
+      return !line.includes('[neopixel-json]');
+    });
+    if (visibleLines.length === 0) return;
+    this.consolePendingText += visibleLines.join('');
     if (this.consoleFlushTimer) return;
     this.consoleFlushTimer = setTimeout(() => {
       const consoleOutput = document.getElementById('console-output');
@@ -1185,8 +1489,8 @@ class TextEditor {
   }
 
   async runPython() {
-    const runFileSelect = document.getElementById('run-file-select');
-    const selectedRunFile = runFileSelect && runFileSelect.value ? runFileSelect.value : this.currentFilePath;
+    const runMainCheckbox = document.getElementById('run-main-checkbox');
+    const selectedRunFile = runMainCheckbox && runMainCheckbox.checked ? 'code/main.py' : this.currentFilePath;
     if (selectedRunFile && selectedRunFile !== this.currentFilePath && this.findTab(selectedRunFile)) {
       this.switchToTab(selectedRunFile);
     }
@@ -1214,6 +1518,7 @@ class TextEditor {
           files[tab.path] = tab.content;
         }
       }
+      this.maybePrepareLedWindow(files);
       this.clearConsole();
       const args = [];
       this.appendConsoleOutput([`$ pyodide ${selectedRunFile}\n`]);
@@ -1228,6 +1533,7 @@ class TextEditor {
       });
       if (generation === this.pyRunGeneration) {
         this.appendConsoleOutput(['\n[Finished]\n']);
+        this.closeLedPanelWindow();
       }
     } catch (error) {
       this.appendConsoleOutput([`\n${error.message}\n`]);
@@ -1244,8 +1550,10 @@ class TextEditor {
     this.pyRunGeneration += 1;
     this.disposePyWorker();
     this.isPythonRunning = false;
+    this.closeLedPanelWindow();
     this.appendConsoleOutput(['\n[Execution stopped — Pyodide worker was reset]\n']);
     this.updateRunButtonState();
+    this.prewarmPyWorker();
   }
 
   async deleteSelected() {
diff --git a/src/static/styles.css b/src/static/styles.css
index b1999ed..8f0c2db 100644
--- a/src/static/styles.css
+++ b/src/static/styles.css
@@ -7,13 +7,14 @@
 body {
   font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
   background-color: #f5f5f5;
-  height: 100vh;
+  height: 100dvh;
   overflow: hidden;
 }
 
 .container {
   display: flex;
-  height: 100vh;
+  height: 100dvh;
+  overflow: hidden;
 }
 
 /* Sidebar */
@@ -23,6 +24,7 @@ body {
   color: white;
   display: flex;
   flex-direction: column;
+  min-height: 0;
 }
 
 .sidebar-header {
@@ -117,6 +119,9 @@ body {
   display: flex;
   flex-direction: column;
   background-color: white;
+  min-width: 0;
+  min-height: 0;
+  overflow: hidden;
 }
 
 .editor-header {
@@ -191,15 +196,6 @@ body {
   gap: 0.5rem;
 }
 
-#run-file-select {
-  min-width: 220px;
-  padding: 0.5rem 0.65rem;
-  border: 1px solid #cbd5e0;
-  border-radius: 6px;
-  font-size: 0.85rem;
-  background: white;
-}
-
 .editor-actions button {
   padding: 0.5rem 1rem;
   border: 1px solid #e2e8f0;
@@ -225,10 +221,28 @@ body {
   background-color: #edf2f7;
 }
 
+.run-main-toggle {
+  display: inline-flex;
+  align-items: center;
+  gap: 0.45rem;
+  border: 1px solid #e2e8f0;
+  border-radius: 6px;
+  padding: 0.4rem 0.6rem;
+  font-size: 0.85rem;
+  color: #374151;
+  background: white;
+  white-space: nowrap;
+}
+
+.run-main-toggle input[type="checkbox"] {
+  margin: 0;
+}
+
 .editor-container {
   flex: 1;
   position: relative;
   min-height: 0;
+  overflow: hidden;
 }
 
 .hidden {
@@ -350,6 +364,89 @@ body {
   background: #0f172a;
 }
 
+.led-sim-panel {
+  border-top: 1px solid #e2e8f0;
+  background: #111827;
+  color: #e5e7eb;
+  padding: 0.75rem;
+}
+
+.led-sim-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  gap: 0.75rem;
+}
+
+.led-sim-header h3 {
+  margin: 0;
+  font-size: 0.95rem;
+  font-weight: 600;
+}
+
+.led-sim-actions {
+  display: flex;
+  align-items: center;
+  gap: 0.4rem;
+}
+
+.led-sim-actions button {
+  padding: 0.3rem 0.65rem;
+  border: 1px solid #374151;
+  background: #1f2937;
+  color: #e5e7eb;
+  border-radius: 6px;
+  cursor: pointer;
+  font-size: 0.8rem;
+}
+
+.led-sim-actions button:hover:not(:disabled) {
+  background: #243244;
+}
+
+.led-sim-actions button:disabled {
+  opacity: 0.5;
+  cursor: not-allowed;
+}
+
+.led-meta {
+  margin-top: 0.5rem;
+  color: #9ca3af;
+  font-size: 0.82rem;
+}
+
+.led-grid {
+  margin-top: 0.6rem;
+  display: flex;
+  flex-wrap: wrap;
+  overflow-x: hidden;
+  overflow-y: auto;
+  gap: 8px;
+  width: 100%;
+  max-height: 132px;
+  padding: 0.1rem 0 0.2rem;
+}
+
+.led-grid.panel-mode {
+  display: grid;
+  grid-template-columns: repeat(16, minmax(0, 24px));
+  grid-auto-rows: 24px;
+  justify-content: start;
+  align-content: start;
+  gap: 6px;
+  max-height: 470px;
+  overflow: auto;
+}
+
+.led {
+  width: 24px;
+  height: 24px;
+  min-width: 24px;
+  border-radius: 50%;
+  border: 1px solid rgba(255, 255, 255, 0.2);
+  box-shadow: inset 0 0 8px rgba(0, 0, 0, 0.45);
+}
+
 .console-header {
   padding: 0.5rem 0.75rem;
   font-size: 0.85rem;
@@ -445,14 +542,106 @@ body {
 
 /* Responsive design */
 @media (max-width: 768px) {
+  body {
+    height: 100dvh;
+    overflow: hidden;
+  }
+
+  .container {
+    flex-direction: column;
+    height: 100dvh;
+    overflow: hidden;
+  }
+
   .sidebar {
-    width: 250px;
+    width: 100%;
+    max-height: 30vh;
+    min-height: 170px;
+  }
+
+  .sidebar-header {
+    padding: 0.7rem 0.8rem;
+  }
+
+  .file-tree {
+    min-height: 100px;
+  }
+
+  .main-content {
+    min-height: 0;
+  }
+
+  .editor-header {
+    padding: 0.65rem;
+    flex-wrap: wrap;
+    gap: 0.55rem;
+    align-items: stretch;
+  }
+
+  .file-info {
+    width: 100%;
+    justify-content: space-between;
+  }
+
+  .mode-toggle {
+    order: 3;
+  }
+
+  .editor-actions {
+    width: 100%;
+    order: 4;
+    flex-wrap: wrap;
+  }
+
+  .editor-actions button {
+    flex: 1 1 100px;
+  }
+
+  .run-main-toggle {
+    width: 100%;
+    justify-content: flex-start;
+    flex: 1 1 100%;
+  }
+
+  .tabs {
+    padding: 0.3rem 0.35rem;
+  }
+
+  .tab-title {
+    max-width: 150px;
+  }
+
+  .editor-container {
+    min-height: 46vh;
+  }
+
+  .cm-editor {
+    font-size: 13px;
   }
   
   .modal-content {
     width: 90%;
     margin: 20% auto;
   }
+
+  .led-grid {
+    max-height: 120px;
+  }
+
+  .led-sim-header {
+    flex-wrap: wrap;
+    align-items: center;
+  }
+
+  .led-sim-actions {
+    width: 100%;
+    justify-content: flex-start;
+    flex-wrap: wrap;
+  }
+
+  .console-container {
+    height: 180px;
+  }
 }
 
 /* Scrollbar styling */
diff --git a/tests/test_led_patterns.py b/tests/test_led_patterns.py
new file mode 100644
index 0000000..014e8bc
--- /dev/null
+++ b/tests/test_led_patterns.py
@@ -0,0 +1,44 @@
+import importlib.util
+from pathlib import Path
+
+
+def _load_patterns_module():
+    repo_root = Path(__file__).resolve().parents[1]
+    module_path = repo_root / "workspace" / "code" / "led_patterns.py"
+    spec = importlib.util.spec_from_file_location("led_patterns", module_path)
+    module = importlib.util.module_from_spec(spec)
+    assert spec is not None and spec.loader is not None
+    spec.loader.exec_module(module)
+    return module
+
+
+def test_rainbow_frame_shape_and_bounds():
+    patterns = _load_patterns_module()
+    frame = patterns.rainbow_frame(12, 3)
+    assert len(frame) == 12
+    for color in frame:
+        assert len(color) == 3
+        assert all(0 <= c <= 255 for c in color)
+
+
+def test_chase_frame_has_head_and_tail():
+    patterns = _load_patterns_module()
+    frame = patterns.chase_frame(8, 5, color=(10, 20, 30), tail=(1, 2, 3))
+    assert len(frame) == 8
+    assert frame[5] == (10, 20, 30)
+    assert frame[4] == (1, 2, 3)
+    assert sum(1 for c in frame if c != (0, 0, 0)) == 2
+
+
+def test_twinkle_frame_is_deterministic_for_same_inputs():
+    patterns = _load_patterns_module()
+    a = patterns.twinkle_frame(20, frame=9, seed=777, sparkles=4)
+    b = patterns.twinkle_frame(20, frame=9, seed=777, sparkles=4)
+    assert a == b
+
+
+def test_twinkle_frame_varies_between_frames():
+    patterns = _load_patterns_module()
+    a = patterns.twinkle_frame(20, frame=1, seed=777, sparkles=4)
+    b = patterns.twinkle_frame(20, frame=2, seed=777, sparkles=4)
+    assert a != b
diff --git a/tests/test_selenium_smoke.py b/tests/test_selenium_smoke.py
index 58b7db6..59bdf70 100644
--- a/tests/test_selenium_smoke.py
+++ b/tests/test_selenium_smoke.py
@@ -7,6 +7,9 @@ import urllib.error
 import urllib.request
 
 import pytest
+from selenium.webdriver.common.by import By
+from selenium.webdriver.support import expected_conditions as ec
+from selenium.webdriver.support.ui import WebDriverWait
 
 pytest.importorskip("selenium.webdriver")
 
@@ -46,3 +49,24 @@ def test_home_page_title(driver):
         )
     driver.get(f"{base}/")
     assert "Python Editor" in driver.title
+
+
+@pytest.mark.selenium
+def test_editor_page_loads_core_controls(driver):
+    base = os.environ.get("SELENIUM_BASE_URL", "http://127.0.0.1:8080").rstrip("/")
+    if not _server_reachable(base):
+        pytest.skip(
+            f"No server at {base}. In another terminal run: "
+            "pipenv run dev   (then re-run this test, or set SELENIUM_BASE_URL)."
+        )
+
+    driver.get(f"{base}/editor")
+
+    # If the app is configured with AUTH_ENABLED=true, unauthenticated requests redirect to /login.
+    if "/login" in (driver.current_url or ""):
+        pytest.skip("Editor requires login; set AUTH_ENABLED=false for this Selenium smoke test.")
+
+    wait = WebDriverWait(driver, 10)
+    wait.until(ec.presence_of_element_located((By.ID, "run-btn")))
+    wait.until(ec.presence_of_element_located((By.ID, "stop-btn")))
+    wait.until(ec.presence_of_element_located((By.ID, "file-tree")))
diff --git a/workspace/code/led_patterns.py b/workspace/code/led_patterns.py
new file mode 100644
index 0000000..875b91a
--- /dev/null
+++ b/workspace/code/led_patterns.py
@@ -0,0 +1,67 @@
+"""LED pattern helpers inspired by embedded NeoPixel drivers."""
+
+from __future__ import annotations
+
+import random
+
+
+Color = tuple[int, int, int]
+
+
+def _clamp(channel: int) -> int:
+    return max(0, min(255, int(channel)))
+
+
+def wheel(pos: int) -> Color:
+    """Return a rainbow color for position 0-255."""
+    pos = 255 - (pos & 255)
+    if pos < 85:
+        return (_clamp(255 - pos * 3), 0, _clamp(pos * 3))
+    if pos < 170:
+        pos -= 85
+        return (0, _clamp(pos * 3), _clamp(255 - pos * 3))
+    pos -= 170
+    return (_clamp(pos * 3), _clamp(255 - pos * 3), 0)
+
+
+def rainbow_frame(led_count: int, frame: int, step: int = 4) -> list[Color]:
+    """Generate one rainbow frame across all LEDs."""
+    if led_count <= 0:
+        return []
+    return [wheel((i * 256 // led_count + frame * step) & 255) for i in range(led_count)]
+
+
+def chase_frame(
+    led_count: int,
+    frame: int,
+    color: Color = (255, 120, 0),
+    tail: Color = (16, 0, 0),
+) -> list[Color]:
+    """Generate a two-pixel chase pattern."""
+    if led_count <= 0:
+        return []
+    out: list[Color] = [(0, 0, 0) for _ in range(led_count)]
+    head = frame % led_count
+    trail = (head - 1) % led_count
+    out[trail] = tuple(_clamp(v) for v in tail)  # type: ignore[assignment]
+    out[head] = tuple(_clamp(v) for v in color)  # type: ignore[assignment]
+    return out
+
+
+def twinkle_frame(
+    led_count: int,
+    frame: int,
+    base: Color = (0, 0, 8),
+    sparkle: Color = (255, 255, 180),
+    sparkles: int = 3,
+    seed: int = 1337,
+) -> list[Color]:
+    """Generate deterministic twinkle frames for testing/replay."""
+    if led_count <= 0:
+        return []
+    out: list[Color] = [tuple(_clamp(v) for v in base) for _ in range(led_count)]  # type: ignore[list-item]
+    rng = random.Random(seed + frame)
+    for _ in range(min(max(0, sparkles), led_count)):
+        idx = rng.randrange(led_count)
+        out[idx] = tuple(_clamp(v) for v in sparkle)  # type: ignore[assignment]
+    return out
diff --git a/workspace/code/led_tutorial.py b/workspace/code/led_tutorial.py
new file mode 100644
index 0000000..6998b39
--- /dev/null
+++ b/workspace/code/led_tutorial.py
@@ -0,0 +1,50 @@
+"""LED tutorial script for NeoPixel in the browser editor.
+
+Run this file and watch the in-app NeoPixel simulator panel.
+"""
+
+from machine import Pin
+import neopixel
+import time
+
+
+LED_COUNT = 12
+np = neopixel.NeoPixel(Pin(4), LED_COUNT)
+
+
+def show_step(title: str):
+    print(f"\n--- {title} ---")
+
+
+show_step("Step 1: single colors")
+np.fill((0, 0, 0))
+np.write()
+time.sleep(0.2)
+np[0] = (255, 0, 0)  # red
+np[1] = (0, 255, 0)  # green
+np[2] = (0, 0, 255)  # blue
+np.write()
+time.sleep(0.8)
+
+show_step("Step 2: fill strip")
+np.fill((40, 0, 120))
+np.write()
+time.sleep(0.6)
+
+show_step("Step 3: moving pixel")
+for i in range(len(np)):
+    np.fill((0, 0, 0))
+    np[i] = (255, 120, 0)
+    np.write()
+    time.sleep(0.06)
+
+show_step("Step 4: simple pulse")
+for level in list(range(0, 200, 20)) + list(range(200, -1, -20)):
+    np.fill((level, 0, level // 3))
+    np.write()
+    time.sleep(0.05)
+
+show_step("Done")
+np.fill((0, 0, 0))
+np.write()
+print("Tutorial complete.")
diff --git a/workspace/code/neopixel_demo.py b/workspace/code/neopixel_demo.py
new file mode 100644
index 0000000..5a84044
--- /dev/null
+++ b/workspace/code/neopixel_demo.py
@@ -0,0 +1,12 @@
+"""Example ESP32 NeoPixel script using mock modules in browser."""
+
+from machine import Pin
+import neopixel
+
+
+np = neopixel.NeoPixel(Pin(4), 8)
+np.fill((0, 0, 0))
+np[0] = (255, 0, 0)
+np[1] = (0, 255, 0)
+np[2] = (0, 0, 255)
+np.write()
diff --git a/workspace/code/neopixel_time_test.py b/workspace/code/neopixel_time_test.py
new file mode 100644
index 0000000..2b57df6
--- /dev/null
+++ b/workspace/code/neopixel_time_test.py
@@ -0,0 +1,32 @@
+"""NeoPixel time-based animation test for the browser simulator."""
+
+from machine import Pin
+import neopixel
+import time
+
+
+np = neopixel.NeoPixel(Pin(4), 50)
+
+
+def wheel(pos: int) -> tuple[int, int, int]:
+    """Generate rainbow colors across 0-255 positions."""
+    pos = 255 - (pos & 255)
+    if pos < 85:
+        return (255 - pos * 3, 0, pos * 3)
+    if pos < 170:
+        pos -= 85
+        return (0, pos * 3, 255 - pos * 3)
+    pos -= 170
+    return (pos * 3, 255 - pos * 3, 0)
+
+
+print("Starting NeoPixel time test...")
+for frame in range(60):
+    for i in range(len(np)):
+        np[i] = wheel((i * 256 // len(np) + frame * 4) & 255)
+    np.write()
+    time.sleep(0.08)
+
+np.fill((0, 0, 0))
+np.write()
+print("NeoPixel time test complete.")
diff --git a/workspace/code/panel16_bounce.py b/workspace/code/panel16_bounce.py
new file mode 100644
index 0000000..cd2a5bb
--- /dev/null
+++ b/workspace/code/panel16_bounce.py
@@ -0,0 +1,41 @@
+"""16x16 bouncing pixel with fading trail."""
+
+from machine import Pin
+import neopixel
+import time
+
+from panel16_utils import PANEL_H, PANEL_W, clamp8, xy_to_index
+
+
+np = neopixel.NeoPixel(Pin(4), PANEL_W * PANEL_H)
+
+trail = [[0 for _ in range(PANEL_W)] for _ in range(PANEL_H)]
+x = 0
+y = 0
+vx = 1
+vy = 1
+
+for _frame in range(420):
+    for yy in range(PANEL_H):
+        for xx in range(PANEL_W):
+            trail[yy][xx] = max(0, trail[yy][xx] - 14)
+
+    trail[y][x] = 255
+
+    for yy in range(PANEL_H):
+        for xx in range(PANEL_W):
+            v = trail[yy][xx]
+            np[xy_to_index(xx, yy)] = (clamp8(v), clamp8(v // 2), clamp8(30))
+
+    np.write()
+    time.sleep(0.02)
+
+    x += vx
+    y += vy
+    if x <= 0 or x >= PANEL_W - 1:
+        vx *= -1
+    if y <= 0 or y >= PANEL_H - 1:
+        vy *= -1
+
+np.fill((0, 0, 0))
+np.write()
diff --git a/workspace/code/panel16_matrix_rain.py b/workspace/code/panel16_matrix_rain.py
new file mode 100644
index 0000000..132338b
--- /dev/null
+++ b/workspace/code/panel16_matrix_rain.py
@@ -0,0 +1,37 @@
+"""16x16 matrix-style rain animation."""
+
+from machine import Pin
+import neopixel
+import random
+import time
+
+from panel16_utils import PANEL_H, PANEL_W, clamp8, xy_to_index
+
+
+np = neopixel.NeoPixel(Pin(4), PANEL_W * PANEL_H)
+rng = random.Random(42)
+
+heads = [rng.randrange(-PANEL_H, 0) for _ in range(PANEL_W)]
+
+for _frame in range(320):
+    for y in range(PANEL_H):
+        for x in range(PANEL_W):
+            np[xy_to_index(x, y)] = (0, 0, 0)
+
+    for x in range(PANEL_W):
+        heads[x] += 1
+        if heads[x] > PANEL_H + 6:
+            heads[x] = rng.randrange(-PANEL_H, 0)
+
+        head_y = heads[x]
+        for tail in range(8):
+            y = head_y - tail
+            if 0 <= y < PANEL_H:
+                brightness = clamp8(255 - tail * 36)
+                np[xy_to_index(x, y)] = (0, brightness, 0)
+
+    np.write()
+    time.sleep(0.045)
+
+np.fill((0, 0, 0))
+np.write()
diff --git a/workspace/code/panel16_rainbow_wave.py b/workspace/code/panel16_rainbow_wave.py
new file mode 100644
index 0000000..b6e0fbe
--- /dev/null
+++ b/workspace/code/panel16_rainbow_wave.py
@@ -0,0 +1,33 @@
+"""16x16 rainbow wave animation."""
+
+from machine import Pin
+import neopixel
+import time
+
+from panel16_utils import PANEL_H, PANEL_W, clamp8, xy_to_index
+
+
+np = neopixel.NeoPixel(Pin(4), PANEL_W * PANEL_H)
+
+
+def wheel(pos: int) -> tuple[int, int, int]:
+    pos = 255 - (pos & 255)
+    if pos < 85:
+        return (clamp8(255 - pos * 3), 0, clamp8(pos * 3))
+    if pos < 170:
+        pos -= 85
+        return (0, clamp8(pos * 3), clamp8(255 - pos * 3))
+    pos -= 170
+    return (clamp8(pos * 3), clamp8(255 - pos * 3), 0)
+
+
+for frame in range(240):
+    for y in range(PANEL_H):
+        for x in range(PANEL_W):
+            color_pos = ((x * 10) + (y * 6) + frame * 5) & 255
+            np[xy_to_index(x, y)] = wheel(color_pos)
+    np.write()
+    time.sleep(0.04)
+
+np.fill((0, 0, 0))
+np.write()
diff --git a/workspace/code/panel16_utils.py b/workspace/code/panel16_utils.py
new file mode 100644
index 0000000..ba48297
--- /dev/null
+++ b/workspace/code/panel16_utils.py
@@ -0,0 +1,26 @@
+"""Helpers for 16x16 serpentine NeoPixel panel animations.
+
+Mapping matches the simulator's 16x16 mode:
+- first LED at top-right
+- row 0 goes right -> left
+- row 1 goes left -> right
+"""
+
+from __future__ import annotations
+
+
+PANEL_W = 16
+PANEL_H = 16
+
+
+def xy_to_index(x: int, y: int, width: int = PANEL_W) -> int:
+    """Map panel coordinate (x, y) to LED index."""
+    x = int(x)
+    y = int(y)
+    if y % 2 == 0:
+        return y * width + (width - 1 - x)
+    return y * width + x
+
+
+def clamp8(v: int) -> int:
+    return max(0, min(255, int(v)))
diff --git a/workspace/code/pattern_chase_demo.py b/workspace/code/pattern_chase_demo.py
new file mode 100644
index 0000000..c47ceff
--- /dev/null
+++ b/workspace/code/pattern_chase_demo.py
@@ -0,0 +1,20 @@
+"""Chase pattern demo using led_patterns helpers."""
+
+from machine import Pin
+import neopixel
+import time
+
+from led_patterns import chase_frame
+
+
+np = neopixel.NeoPixel(Pin(4), 24)
+
+for frame in range(120):
+    frame_colors = chase_frame(len(np), frame, color=(0, 220, 255), tail=(0, 40, 55))
+    for i, color in enumerate(frame_colors):
+        np[i] = color
+    np.write()
+    time.sleep(0.05)
+
+np.fill((0, 0, 0))
+np.write()
diff --git a/workspace/code/pattern_rainbow_demo.py b/workspace/code/pattern_rainbow_demo.py
new file mode 100644
index 0000000..421e66b
--- /dev/null
+++ b/workspace/code/pattern_rainbow_demo.py
@@ -0,0 +1,20 @@
+"""Rainbow pattern demo using led_patterns helpers."""
+
+from machine import Pin
+import neopixel
+import time
+
+from led_patterns import rainbow_frame
+
+
+np = neopixel.NeoPixel(Pin(4), 256)
+
+for frame in range(120):
+    frame_colors = rainbow_frame(len(np), frame, step=5)
+    for i, color in enumerate(frame_colors):
+        np[i] = color
+    np.write()
+    time.sleep(0.05)
+
+np.fill((0, 0, 0))
+np.write()
diff --git a/workspace/code/pattern_twinkle_demo.py b/workspace/code/pattern_twinkle_demo.py
new file mode 100644
index 0000000..fbe38ae
--- /dev/null
+++ b/workspace/code/pattern_twinkle_demo.py
@@ -0,0 +1,26 @@
+"""Twinkle pattern demo using led_patterns helpers."""
+
+from machine import Pin
+import neopixel
+import time
+
+from led_patterns import twinkle_frame
+
+
+np = neopixel.NeoPixel(Pin(4), 36)
+
+for frame in range(120):
+    frame_colors = twinkle_frame(
+        len(np),
+        frame,
+        base=(0, 0, 6),
+        sparkle=(255, 210, 130),
+        sparkles=5,
+    )
+    for i, color in enumerate(frame_colors):
+        np[i] = color
+    np.write()
+    time.sleep(0.08)
+
+np.fill((0, 0, 0))
+np.write()
diff --git a/workspace/lib/led_patterns.py b/workspace/lib/led_patterns.py
new file mode 100644
index 0000000..dcf1667
--- /dev/null
+++ b/workspace/lib/led_patterns.py
@@ -0,0 +1,68 @@
+"""Compatibility pattern helpers for NeoPixel demos.
+
+This file mirrors `workspace/code/led_patterns.py` so imports like
+`from led_patterns import ...` work even in older worker sessions that only
+include `/workspace/lib` in `sys.path`.
+"""
+
+from __future__ import annotations
+
+import random
+
+
+Color = tuple[int, int, int]
+
+
+def _clamp(channel: int) -> int:
+    return max(0, min(255, int(channel)))
+
+
+def wheel(pos: int) -> Color:
+    pos = 255 - (pos & 255)
+    if pos < 85:
+        return (_clamp(255 - pos * 3), 0, _clamp(pos * 3))
+    if pos < 170:
+        pos -= 85
+        return (0, _clamp(pos * 3), _clamp(255 - pos * 3))
+    pos -= 170
+    return (_clamp(pos * 3), _clamp(255 - pos * 3), 0)
+
+
+def rainbow_frame(led_count: int, frame: int, step: int = 4) -> list[Color]:
+    if led_count <= 0:
+        return []
+    return [wheel((i * 256 // led_count + frame * step) & 255) for i in range(led_count)]
+
+
+def chase_frame(
+    led_count: int,
+    frame: int,
+    color: Color = (255, 120, 0),
+    tail: Color = (16, 0, 0),
+) -> list[Color]:
+    if led_count <= 0:
+        return []
+    out: list[Color] = [(0, 0, 0) for _ in range(led_count)]
+    head = frame % led_count
+    trail = (head - 1) % led_count
+    out[trail] = tuple(_clamp(v) for v in tail)  # type: ignore[assignment]
+    out[head] = tuple(_clamp(v) for v in color)  # type: ignore[assignment]
+    return out
+
+
+def twinkle_frame(
+    led_count: int,
+    frame: int,
+    base: Color = (0, 0, 8),
+    sparkle: Color = (255, 255, 180),
+    sparkles: int = 3,
+    seed: int = 1337,
+) -> list[Color]:
+    if led_count <= 0:
+        return []
+    out: list[Color] = [tuple(_clamp(v) for v in base) for _ in range(led_count)]  # type: ignore[list-item]
+    rng = random.Random(seed + frame)
+    for _ in range(min(max(0, sparkles), led_count)):
+        idx = rng.randrange(led_count)
+        out[idx] = tuple(_clamp(v) for v in sparkle)  # type: ignore[assignment]
+    return out
diff --git a/workspace/lib/machine.py b/workspace/lib/machine.py
new file mode 100644
index 0000000..eb0a242
--- /dev/null
+++ b/workspace/lib/machine.py
@@ -0,0 +1,19 @@
+"""Minimal MicroPython-style machine module mock for browser simulation."""
+
+
+class Pin:
+    IN = 0
+    OUT = 1
+    PULL_UP = 2
+    PULL_DOWN = 3
+
+    def __init__(self, pin_id: int, mode: int = OUT, value: int = 0):
+        self.id = int(pin_id)
+        self.mode = int(mode)
+        self._value = 1 if value else 0
+
+    def value(self, new_value=None):
+        if new_value is None:
+            return self._value
+        self._value = 1 if int(new_value) else 0
+        return self._value
diff --git a/workspace/lib/neopixel.py b/workspace/lib/neopixel.py
new file mode 100644
index 0000000..9446b38
--- /dev/null
+++ b/workspace/lib/neopixel.py
@@ -0,0 +1,56 @@
+"""NeoPixel mock for Pyodide/browser execution.
+
+Supports a useful subset of MicroPython's neopixel.NeoPixel API:
+- NeoPixel(pin, n, bpp=3, timing=1)
+- __setitem__, __getitem__, __len__
+- fill(color)
+- write()  # prints current pixel buffer snapshot
+"""
+
+import json
+
+
+def _normalize_color(value, bpp: int):
+    if not hasattr(value, "__iter__"):
+        raise TypeError("Color must be an iterable, e.g. (r, g, b)")
+    parts = [int(v) for v in value]
+    if len(parts) != bpp:
+        raise ValueError(f"Expected {bpp} color channels, got {len(parts)}")
+    out = []
+    for channel in parts:
+        out.append(max(0, min(255, channel)))
+    return tuple(out)
+
+
+class NeoPixel:
+    def __init__(self, pin, n: int, bpp: int = 3, timing: int = 1):
+        self.pin = pin
+        self.n = int(n)
+        self.bpp = int(bpp)
+        self.timing = int(timing)
+        self._buf = [tuple([0] * self.bpp) for _ in range(self.n)]
+
+    def __len__(self):
+        return self.n
+
+    def __getitem__(self, index):
+        return self._buf[int(index)]
+
+    def __setitem__(self, index, color):
+        idx = int(index)
+        self._buf[idx] = _normalize_color(color, self.bpp)
+
+    def fill(self, color):
+        c = _normalize_color(color, self.bpp)
+        for i in range(self.n):
+            self._buf[i] = c
+
+    def write(self):
+        pin_id = getattr(self.pin, "id", self.pin)
+        payload = {
+            "type": "neopixel",
+            "pin": pin_id,
+            "pixels": [list(pixel) for pixel in self._buf],
+            "bpp": self.bpp,
+        }
+        print("[neopixel-json]" + json.dumps(payload))