Codebase audit fixes: stability, performance, accessibility

- Fix CORS: set allow_credentials=False (token auth, not cookies)
- Add threading.Lock for position cache thread safety
- Add shutdown_executor() for clean ThreadPoolExecutor cleanup
- Dedicated ThreadPoolExecutors for script/callback execution
- Fix Mutagen file handle leaks with try/finally close
- Reduce idle WebSocket polling (0.5s → 2.0s when no clients)
- Add :focus-visible styles for playback control buttons
- Add aria-label to icon-only header buttons
- Dynamic album art alt text for screen readers
- Persist MDI icon cache to localStorage

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

media_server/main.py

@@ -87,6 +87,13 @@ async def lifespan(app: FastAPI):
 
     # Stop WebSocket status monitor
     await ws_manager.stop_status_monitor()
+
+    # Clean up platform-specific resources
+    import platform as _platform
+    if _platform.system() == "Windows":
+        from .services.windows_media import shutdown_executor
+        shutdown_executor()
+
     logger.info("Media Server shutting down")
 
 
@@ -103,10 +110,11 @@ def create_app() -> FastAPI:
     app.add_middleware(GZipMiddleware, minimum_size=1000)
 
     # Add CORS middleware for cross-origin requests
+    # Token auth is via Authorization header, not cookies, so credentials are not needed
     app.add_middleware(
         CORSMiddleware,
         allow_origins=["*"],
-        allow_credentials=True,
+        allow_credentials=False,
         allow_methods=["*"],
         allow_headers=["*"],
     )

media_server/routes/callbacks.py

@@ -5,6 +5,7 @@ import logging
 import re
 import subprocess
 import time
+from concurrent.futures import ThreadPoolExecutor
 from typing import Any
 
 from fastapi import APIRouter, Depends, HTTPException, status
@@ -17,6 +18,9 @@ from ..config_manager import config_manager
 router = APIRouter(prefix="/api/callbacks", tags=["callbacks"])
 logger = logging.getLogger(__name__)
 
+# Dedicated executor for callback/subprocess execution
+_callback_executor = ThreadPoolExecutor(max_workers=4, thread_name_prefix="callback")
+
 
 class CallbackInfo(BaseModel):
     """Information about a configured callback."""
@@ -127,10 +131,10 @@ async def execute_callback(
     logger.info(f"Executing callback for debugging: {callback_name}")
 
     try:
-        # Execute in thread pool to not block
+        # Execute in dedicated thread pool to not block the default executor
         loop = asyncio.get_event_loop()
         result = await loop.run_in_executor(
-            None,
+            _callback_executor,
             lambda: _run_callback(
                 command=callback_config.command,
                 timeout=callback_config.timeout,

media_server/routes/scripts.py

@@ -5,6 +5,7 @@ import logging
 import re
 import subprocess
 import time
+from concurrent.futures import ThreadPoolExecutor
 from typing import Any
 
 from fastapi import APIRouter, Depends, HTTPException, status
@@ -16,6 +17,9 @@ from ..config_manager import config_manager
 from ..services.websocket_manager import ws_manager
 
 router = APIRouter(prefix="/api/scripts", tags=["scripts"])
+
+# Dedicated executor for script/subprocess execution (avoids blocking the default pool)
+_script_executor = ThreadPoolExecutor(max_workers=4, thread_name_prefix="script")
 logger = logging.getLogger(__name__)
 
 
@@ -101,10 +105,10 @@ async def execute_script(
             # Append arguments to command
             command = f"{command} {' '.join(args)}"
 
-        # Execute in thread pool to not block
+        # Execute in dedicated thread pool to not block the default executor
         loop = asyncio.get_event_loop()
         result = await loop.run_in_executor(
-            None,
+            _script_executor,
             lambda: _run_script(
                 command=command,
                 timeout=script_config.timeout,

media_server/services/metadata_service.py

@@ -28,61 +28,65 @@ class MetadataService:
             if audio is None:
                 return {"error": "Unable to read audio file"}
 
-            metadata = {
-                "type": "audio",
-                "filename": file_path.name,
-                "path": str(file_path),
-            }
+            try:
+                metadata = {
+                    "type": "audio",
+                    "filename": file_path.name,
+                    "path": str(file_path),
+                }
 
-            # Extract duration
-            if hasattr(audio.info, "length"):
-                metadata["duration"] = round(audio.info.length, 2)
+                # Extract duration
+                if hasattr(audio.info, "length"):
+                    metadata["duration"] = round(audio.info.length, 2)
 
-            # Extract bitrate
-            if hasattr(audio.info, "bitrate"):
-                metadata["bitrate"] = audio.info.bitrate
+                # Extract bitrate
+                if hasattr(audio.info, "bitrate"):
+                    metadata["bitrate"] = audio.info.bitrate
 
-            # Extract sample rate
-            if hasattr(audio.info, "sample_rate"):
-                metadata["sample_rate"] = audio.info.sample_rate
-            elif hasattr(audio.info, "samplerate"):
-                metadata["sample_rate"] = audio.info.samplerate
+                # Extract sample rate
+                if hasattr(audio.info, "sample_rate"):
+                    metadata["sample_rate"] = audio.info.sample_rate
+                elif hasattr(audio.info, "samplerate"):
+                    metadata["sample_rate"] = audio.info.samplerate
 
-            # Extract channels
-            if hasattr(audio.info, "channels"):
-                metadata["channels"] = audio.info.channels
+                # Extract channels
+                if hasattr(audio.info, "channels"):
+                    metadata["channels"] = audio.info.channels
 
-            # Extract tags (use easy=True for consistent tag names)
-            if audio is not None and hasattr(audio, "tags") and audio.tags:
-                # Easy tags provide lists, so we take the first item
-                tags = audio.tags
+                # Extract tags (use easy=True for consistent tag names)
+                if audio is not None and hasattr(audio, "tags") and audio.tags:
+                    # Easy tags provide lists, so we take the first item
+                    tags = audio.tags
 
-                if "title" in tags:
-                    metadata["title"] = tags["title"][0] if isinstance(tags["title"], list) else tags["title"]
+                    if "title" in tags:
+                        metadata["title"] = tags["title"][0] if isinstance(tags["title"], list) else tags["title"]
 
-                if "artist" in tags:
-                    metadata["artist"] = tags["artist"][0] if isinstance(tags["artist"], list) else tags["artist"]
+                    if "artist" in tags:
+                        metadata["artist"] = tags["artist"][0] if isinstance(tags["artist"], list) else tags["artist"]
 
-                if "album" in tags:
-                    metadata["album"] = tags["album"][0] if isinstance(tags["album"], list) else tags["album"]
+                    if "album" in tags:
+                        metadata["album"] = tags["album"][0] if isinstance(tags["album"], list) else tags["album"]
 
-                if "albumartist" in tags:
-                    metadata["album_artist"] = tags["albumartist"][0] if isinstance(tags["albumartist"], list) else tags["albumartist"]
+                    if "albumartist" in tags:
+                        metadata["album_artist"] = tags["albumartist"][0] if isinstance(tags["albumartist"], list) else tags["albumartist"]
 
-                if "date" in tags:
-                    metadata["date"] = tags["date"][0] if isinstance(tags["date"], list) else tags["date"]
+                    if "date" in tags:
+                        metadata["date"] = tags["date"][0] if isinstance(tags["date"], list) else tags["date"]
 
-                if "genre" in tags:
-                    metadata["genre"] = tags["genre"][0] if isinstance(tags["genre"], list) else tags["genre"]
+                    if "genre" in tags:
+                        metadata["genre"] = tags["genre"][0] if isinstance(tags["genre"], list) else tags["genre"]
 
-                if "tracknumber" in tags:
-                    metadata["track_number"] = tags["tracknumber"][0] if isinstance(tags["tracknumber"], list) else tags["tracknumber"]
+                    if "tracknumber" in tags:
+                        metadata["track_number"] = tags["tracknumber"][0] if isinstance(tags["tracknumber"], list) else tags["tracknumber"]
 
-            # If no title tag, use filename
-            if "title" not in metadata:
-                metadata["title"] = file_path.stem
+                # If no title tag, use filename
+                if "title" not in metadata:
+                    metadata["title"] = file_path.stem
 
-            return metadata
+                return metadata
+            finally:
+                if hasattr(audio, 'close'):
+                    audio.close()
 
         except ImportError:
             logger.error("mutagen library not installed, cannot extract metadata")
@@ -117,40 +121,44 @@ class MetadataService:
                     "title": file_path.stem,
                 }
 
-            metadata = {
-                "type": "video",
-                "filename": file_path.name,
-                "path": str(file_path),
-            }
+            try:
+                metadata = {
+                    "type": "video",
+                    "filename": file_path.name,
+                    "path": str(file_path),
+                }
 
-            # Extract duration
-            if hasattr(video.info, "length"):
-                metadata["duration"] = round(video.info.length, 2)
+                # Extract duration
+                if hasattr(video.info, "length"):
+                    metadata["duration"] = round(video.info.length, 2)
 
-            # Extract bitrate
-            if hasattr(video.info, "bitrate"):
-                metadata["bitrate"] = video.info.bitrate
+                # Extract bitrate
+                if hasattr(video.info, "bitrate"):
+                    metadata["bitrate"] = video.info.bitrate
 
-            # Extract video-specific properties if available
-            if hasattr(video.info, "width"):
-                metadata["width"] = video.info.width
+                # Extract video-specific properties if available
+                if hasattr(video.info, "width"):
+                    metadata["width"] = video.info.width
 
-            if hasattr(video.info, "height"):
-                metadata["height"] = video.info.height
+                if hasattr(video.info, "height"):
+                    metadata["height"] = video.info.height
 
-            # Try to extract title from tags
-            if hasattr(video, "tags") and video.tags:
-                tags = video.tags
-                if hasattr(tags, "get"):
-                    title = tags.get("title") or tags.get("TITLE") or tags.get("\xa9nam")
-                    if title:
-                        metadata["title"] = title[0] if isinstance(title, list) else str(title)
+                # Try to extract title from tags
+                if hasattr(video, "tags") and video.tags:
+                    tags = video.tags
+                    if hasattr(tags, "get"):
+                        title = tags.get("title") or tags.get("TITLE") or tags.get("\xa9nam")
+                        if title:
+                            metadata["title"] = title[0] if isinstance(title, list) else str(title)
 
-            # If no title tag, use filename
-            if "title" not in metadata:
-                metadata["title"] = file_path.stem
+                # If no title tag, use filename
+                if "title" not in metadata:
+                    metadata["title"] = file_path.stem
 
-            return metadata
+                return metadata
+            finally:
+                if hasattr(video, 'close'):
+                    video.close()
 
         except ImportError:
             logger.error("mutagen library not installed, cannot extract metadata")

media_server/services/websocket_manager.py

@@ -251,7 +251,7 @@ class ConnectionManager:
                     has_clients = len(self._active_connections) > 0
 
                 if not has_clients:
-                    await asyncio.sleep(self._poll_interval)
+                    await asyncio.sleep(2.0)  # Sleep longer when no clients connected
                     continue
 
                 status = await get_status_func()

media_server/services/windows_media.py

@@ -2,6 +2,8 @@
 
 import asyncio
 import logging
+import threading
+import time as _time
 from concurrent.futures import ThreadPoolExecutor
 from typing import Optional, Any
 
@@ -16,8 +18,10 @@ _executor = ThreadPoolExecutor(max_workers=2, thread_name_prefix="winrt")
 # Global storage for current album art (as bytes)
 _current_album_art_bytes: bytes | None = None
 
+# Lock protecting _position_cache and _track_skip_pending from concurrent access
+_position_lock = threading.Lock()
+
 # Global storage for position tracking
-import time as _time
 _position_cache = {
     "track_id": "",
     "base_position": 0.0,
@@ -224,124 +228,125 @@ def _sync_get_media_status() -> dict[str, Any]:
                         is_playing = result["state"] == "playing"
                         current_title = result.get('title', '')
 
-                        # Check if track skip is pending and title changed
-                        skip_just_completed = False
-                        if _track_skip_pending["active"]:
-                            if current_title and current_title != _track_skip_pending["old_title"]:
-                                # Title changed - clear the skip flag and start grace period
-                                _track_skip_pending["active"] = False
-                                _track_skip_pending["old_title"] = ""
-                                _track_skip_pending["grace_until"] = current_time + 300.0  # Long grace period
-                                _track_skip_pending["stale_pos"] = -999  # Reset stale position tracking
-                                skip_just_completed = True
-                                # Reset position cache for new track
-                                new_track_id = f"{current_title}:{result.get('artist', '')}:{result.get('duration', 0)}"
-                                _position_cache["track_id"] = new_track_id
+                        with _position_lock:
+                            # Check if track skip is pending and title changed
+                            skip_just_completed = False
+                            if _track_skip_pending["active"]:
+                                if current_title and current_title != _track_skip_pending["old_title"]:
+                                    # Title changed - clear the skip flag and start grace period
+                                    _track_skip_pending["active"] = False
+                                    _track_skip_pending["old_title"] = ""
+                                    _track_skip_pending["grace_until"] = current_time + 300.0  # Long grace period
+                                    _track_skip_pending["stale_pos"] = -999  # Reset stale position tracking
+                                    skip_just_completed = True
+                                    # Reset position cache for new track
+                                    new_track_id = f"{current_title}:{result.get('artist', '')}:{result.get('duration', 0)}"
+                                    _position_cache["track_id"] = new_track_id
+                                    _position_cache["base_position"] = 0.0
+                                    _position_cache["base_time"] = current_time
+                                    _position_cache["last_smtc_pos"] = -999  # Force fresh start
+                                    _position_cache["is_playing"] = is_playing
+                                    logger.debug(f"Track skip complete, new title: {current_title}, grace until: {_track_skip_pending['grace_until']}")
+                                elif current_time - _track_skip_pending["skip_time"] > 5.0:
+                                    # Timeout after 5 seconds
+                                    _track_skip_pending["active"] = False
+                                    logger.debug("Track skip timeout")
+
+                            # Check if we're in grace period (after skip, ignore high SMTC positions)
+                            in_grace_period = current_time < _track_skip_pending.get("grace_until", 0)
+
+                            # If track skip is pending or just completed, use cached/reset position
+                            if _track_skip_pending["active"]:
+                                pos = 0.0
                                 _position_cache["base_position"] = 0.0
                                 _position_cache["base_time"] = current_time
-                                _position_cache["last_smtc_pos"] = -999  # Force fresh start
                                 _position_cache["is_playing"] = is_playing
-                                logger.debug(f"Track skip complete, new title: {current_title}, grace until: {_track_skip_pending['grace_until']}")
-                            elif current_time - _track_skip_pending["skip_time"] > 5.0:
-                                # Timeout after 5 seconds
-                                _track_skip_pending["active"] = False
-                                logger.debug("Track skip timeout")
+                            elif skip_just_completed:
+                                # Just completed skip - interpolate from 0
+                                if is_playing:
+                                    elapsed = current_time - _position_cache["base_time"]
+                                    pos = elapsed
+                                else:
+                                    pos = 0.0
+                            elif in_grace_period:
+                                # Grace period after track skip
+                                # SMTC position is stale (from old track) and won't update until seek/pause
+                                # We interpolate from 0 and only trust SMTC when it changes or reports low value
 
-                        # Check if we're in grace period (after skip, ignore high SMTC positions)
-                        in_grace_period = current_time < _track_skip_pending.get("grace_until", 0)
+                                # Calculate interpolated position from start of new track
+                                if is_playing:
+                                    elapsed = current_time - _position_cache.get("base_time", current_time)
+                                    interpolated_pos = _position_cache.get("base_position", 0.0) + elapsed
+                                else:
+                                    interpolated_pos = _position_cache.get("base_position", 0.0)
 
-                        # If track skip is pending or just completed, use cached/reset position
-                        if _track_skip_pending["active"]:
-                            pos = 0.0
-                            _position_cache["base_position"] = 0.0
-                            _position_cache["base_time"] = current_time
-                            _position_cache["is_playing"] = is_playing
-                        elif skip_just_completed:
-                            # Just completed skip - interpolate from 0
-                            if is_playing:
-                                elapsed = current_time - _position_cache["base_time"]
-                                pos = elapsed
+                                # Get the stale position we've been tracking
+                                stale_pos = _track_skip_pending.get("stale_pos", -999)
+
+                                # Detect if SMTC position changed significantly from the stale value (user seeked)
+                                smtc_changed = stale_pos >= 0 and abs(smtc_pos - stale_pos) > 3.0
+
+                                # Trust SMTC if:
+                                # 1. It reports a low position (indicating new track started)
+                                # 2. It changed from the stale value (user seeked)
+                                if smtc_pos < 10.0 or smtc_changed:
+                                    # SMTC is now trustworthy
+                                    _position_cache["base_position"] = smtc_pos
+                                    _position_cache["base_time"] = current_time
+                                    _position_cache["last_smtc_pos"] = smtc_pos
+                                    _position_cache["is_playing"] = is_playing
+                                    pos = smtc_pos
+                                    _track_skip_pending["grace_until"] = 0
+                                    _track_skip_pending["stale_pos"] = -999
+                                    logger.debug(f"Grace period: accepting SMTC pos {smtc_pos} (low={smtc_pos < 10}, changed={smtc_changed})")
+                                else:
+                                    # SMTC is stale - keep interpolating
+                                    pos = interpolated_pos
+                                    # Record the stale position for change detection
+                                    if stale_pos < 0:
+                                        _track_skip_pending["stale_pos"] = smtc_pos
+                                    # Keep grace period active indefinitely while SMTC is stale
+                                    _track_skip_pending["grace_until"] = current_time + 300.0
+                                    logger.debug(f"Grace period: SMTC stale ({smtc_pos}), using interpolated {interpolated_pos}")
                             else:
-                                pos = 0.0
-                        elif in_grace_period:
-                            # Grace period after track skip
-                            # SMTC position is stale (from old track) and won't update until seek/pause
-                            # We interpolate from 0 and only trust SMTC when it changes or reports low value
+                                # Normal position tracking
+                                # Create track ID from title + artist + duration
+                                track_id = f"{current_title}:{result.get('artist', '')}:{result.get('duration', 0)}"
 
-                            # Calculate interpolated position from start of new track
-                            if is_playing:
-                                elapsed = current_time - _position_cache.get("base_time", current_time)
-                                interpolated_pos = _position_cache.get("base_position", 0.0) + elapsed
-                            else:
-                                interpolated_pos = _position_cache.get("base_position", 0.0)
+                                # Detect if SMTC position changed (new track, seek, or state change)
+                                smtc_pos_changed = abs(smtc_pos - _position_cache.get("last_smtc_pos", -999)) > 0.5
+                                track_changed = track_id != _position_cache.get("track_id", "")
 
-                            # Get the stale position we've been tracking
-                            stale_pos = _track_skip_pending.get("stale_pos", -999)
+                                if smtc_pos_changed or track_changed:
+                                    # SMTC updated - store new baseline
+                                    _position_cache["track_id"] = track_id
+                                    _position_cache["last_smtc_pos"] = smtc_pos
+                                    _position_cache["base_position"] = smtc_pos
+                                    _position_cache["base_time"] = current_time
+                                    _position_cache["is_playing"] = is_playing
+                                    pos = smtc_pos
+                                elif is_playing:
+                                    # Interpolate position based on elapsed time
+                                    elapsed = current_time - _position_cache.get("base_time", current_time)
+                                    pos = _position_cache.get("base_position", smtc_pos) + elapsed
+                                else:
+                                    # Paused - use base position
+                                    pos = _position_cache.get("base_position", smtc_pos)
 
-                            # Detect if SMTC position changed significantly from the stale value (user seeked)
-                            smtc_changed = stale_pos >= 0 and abs(smtc_pos - stale_pos) > 3.0
+                                # Update playing state
+                                if _position_cache.get("is_playing") != is_playing:
+                                    _position_cache["base_position"] = pos if is_playing else _position_cache.get("base_position", smtc_pos)
+                                    _position_cache["base_time"] = current_time
+                                    _position_cache["is_playing"] = is_playing
 
-                            # Trust SMTC if:
-                            # 1. It reports a low position (indicating new track started)
-                            # 2. It changed from the stale value (user seeked)
-                            if smtc_pos < 10.0 or smtc_changed:
-                                # SMTC is now trustworthy
-                                _position_cache["base_position"] = smtc_pos
-                                _position_cache["base_time"] = current_time
-                                _position_cache["last_smtc_pos"] = smtc_pos
-                                _position_cache["is_playing"] = is_playing
-                                pos = smtc_pos
-                                _track_skip_pending["grace_until"] = 0
-                                _track_skip_pending["stale_pos"] = -999
-                                logger.debug(f"Grace period: accepting SMTC pos {smtc_pos} (low={smtc_pos < 10}, changed={smtc_changed})")
-                            else:
-                                # SMTC is stale - keep interpolating
-                                pos = interpolated_pos
-                                # Record the stale position for change detection
-                                if stale_pos < 0:
-                                    _track_skip_pending["stale_pos"] = smtc_pos
-                                # Keep grace period active indefinitely while SMTC is stale
-                                _track_skip_pending["grace_until"] = current_time + 300.0
-                                logger.debug(f"Grace period: SMTC stale ({smtc_pos}), using interpolated {interpolated_pos}")
-                        else:
-                            # Normal position tracking
-                            # Create track ID from title + artist + duration
-                            track_id = f"{current_title}:{result.get('artist', '')}:{result.get('duration', 0)}"
-
-                            # Detect if SMTC position changed (new track, seek, or state change)
-                            smtc_pos_changed = abs(smtc_pos - _position_cache.get("last_smtc_pos", -999)) > 0.5
-                            track_changed = track_id != _position_cache.get("track_id", "")
-
-                            if smtc_pos_changed or track_changed:
-                                # SMTC updated - store new baseline
-                                _position_cache["track_id"] = track_id
-                                _position_cache["last_smtc_pos"] = smtc_pos
-                                _position_cache["base_position"] = smtc_pos
-                                _position_cache["base_time"] = current_time
-                                _position_cache["is_playing"] = is_playing
-                                pos = smtc_pos
-                            elif is_playing:
-                                # Interpolate position based on elapsed time
-                                elapsed = current_time - _position_cache.get("base_time", current_time)
-                                pos = _position_cache.get("base_position", smtc_pos) + elapsed
-                            else:
-                                # Paused - use base position
-                                pos = _position_cache.get("base_position", smtc_pos)
-
-                            # Update playing state
-                            if _position_cache.get("is_playing") != is_playing:
-                                _position_cache["base_position"] = pos if is_playing else _position_cache.get("base_position", smtc_pos)
-                                _position_cache["base_time"] = current_time
-                                _position_cache["is_playing"] = is_playing
-
-                        # Sanity check: position should be non-negative and <= duration
-                        if pos >= 0:
-                            if result["duration"] and pos <= result["duration"]:
-                                result["position"] = pos
-                            elif result["duration"] and pos > result["duration"]:
-                                result["position"] = result["duration"]
-                            elif not result["duration"]:
-                                result["position"] = pos
+                            # Sanity check: position should be non-negative and <= duration
+                            if pos >= 0:
+                                if result["duration"] and pos <= result["duration"]:
+                                    result["position"] = pos
+                                elif result["duration"] and pos > result["duration"]:
+                                    result["position"] = result["duration"]
+                                elif not result["duration"]:
+                                    result["position"] = pos
 
                     logger.debug(f"Timeline: duration={result['duration']}, position={result['position']}")
                 except Exception as e:
@@ -483,6 +488,11 @@ def _sync_seek(position: float) -> bool:
         return False
 
 
+def shutdown_executor() -> None:
+    """Shut down the WinRT thread pool executor."""
+    _executor.shutdown(wait=False)
+
+
 class WindowsMediaController(MediaController):
     """Media controller for Windows using WinRT and pycaw."""
 
@@ -602,10 +612,10 @@ class WindowsMediaController(MediaController):
 
         result = await self._run_command("next")
         if result:
-            # Set flag to force position to 0 until title changes
-            _track_skip_pending["active"] = True
-            _track_skip_pending["old_title"] = old_title
-            _track_skip_pending["skip_time"] = _time.time()
+            with _position_lock:
+                _track_skip_pending["active"] = True
+                _track_skip_pending["old_title"] = old_title
+                _track_skip_pending["skip_time"] = _time.time()
             logger.debug(f"Track skip initiated, old title: {old_title}")
         return result
 
@@ -620,10 +630,10 @@ class WindowsMediaController(MediaController):
 
         result = await self._run_command("previous")
         if result:
-            # Set flag to force position to 0 until title changes
-            _track_skip_pending["active"] = True
-            _track_skip_pending["old_title"] = old_title
-            _track_skip_pending["skip_time"] = _time.time()
+            with _position_lock:
+                _track_skip_pending["active"] = True
+                _track_skip_pending["old_title"] = old_title
+                _track_skip_pending["skip_time"] = _time.time()
             logger.debug(f"Track skip initiated, old title: {old_title}")
         return result
 

media_server/static/css/styles.css

@@ -824,6 +824,20 @@ button:disabled {
     transform: scale(1.05);
 }
 
+.controls button:focus-visible {
+    outline: 2px solid var(--accent);
+    outline-offset: 3px;
+    box-shadow: 0 0 0 4px rgba(29, 185, 84, 0.25);
+}
+
+.mute-btn:focus-visible,
+.mini-control-btn:focus-visible,
+.vinyl-toggle-btn:focus-visible {
+    outline: 2px solid var(--accent);
+    outline-offset: 2px;
+    box-shadow: 0 0 0 4px rgba(29, 185, 84, 0.25);
+}
+
 .controls button.primary {
     width: 56px;
     height: 56px;

media_server/static/index.html

@@ -74,12 +74,12 @@
             <div class="header-toolbar">
                 <div id="headerLinks" class="header-links"></div>
                 <div class="accent-picker">
-                    <button class="header-btn" onclick="toggleAccentPicker()" title="Accent color">
+                    <button class="header-btn" onclick="toggleAccentPicker()" title="Accent color" aria-label="Accent color">
                         <span class="accent-dot" id="accentDot"></span>
                     </button>
                     <div class="accent-picker-dropdown" id="accentDropdown"></div>
                 </div>
-                <button class="header-btn" onclick="toggleTheme()" data-i18n-title="player.theme" title="Toggle theme" id="theme-toggle">
+                <button class="header-btn" onclick="toggleTheme()" data-i18n-title="player.theme" title="Toggle theme" aria-label="Toggle theme" id="theme-toggle">
                     <svg id="theme-icon-sun" viewBox="0 0 24 24" style="display: none;">
                         <path d="M12 7c-2.76 0-5 2.24-5 5s2.24 5 5 5 5-2.24 5-5-2.24-5-5-5zM2 13h2c.55 0 1-.45 1-1s-.45-1-1-1H2c-.55 0-1 .45-1 1s.45 1 1 1zm18 0h2c.55 0 1-.45 1-1s-.45-1-1-1h-2c-.55 0-1 .45-1 1s.45 1 1 1zM11 2v2c0 .55.45 1 1 1s1-.45 1-1V2c0-.55-.45-1-1-1s-1 .45-1 1zm0 18v2c0 .55.45 1 1 1s1-.45 1-1v-2c0-.55-.45-1-1-1s-1 .45-1 1zM5.99 4.58c-.39-.39-1.03-.39-1.41 0-.39.39-.39 1.03 0 1.41l1.06 1.06c.39.39 1.03.39 1.41 0s.39-1.03 0-1.41L5.99 4.58zm12.37 12.37c-.39-.39-1.03-.39-1.41 0-.39.39-.39 1.03 0 1.41l1.06 1.06c.39.39 1.03.39 1.41 0 .39-.39.39-1.03 0-1.41l-1.06-1.06zm1.06-10.96c.39-.39.39-1.03 0-1.41-.39-.39-1.03-.39-1.41 0l-1.06 1.06c-.39.39-.39 1.03 0 1.41s1.03.39 1.41 0l1.06-1.06zM7.05 18.36c.39-.39.39-1.03 0-1.41-.39-.39-1.03-.39-1.41 0l-1.06 1.06c-.39.39-.39 1.03 0 1.41s1.03.39 1.41 0l1.06-1.06z"/>
                     </svg>
@@ -92,7 +92,7 @@
                     <option value="ru">RU</option>
                 </select>
                 <span class="header-toolbar-sep"></span>
-                <button class="header-btn header-btn-logout" onclick="clearToken()" data-i18n-title="auth.logout.title" title="Clear saved token">
+                <button class="header-btn header-btn-logout" onclick="clearToken()" data-i18n-title="auth.logout.title" title="Clear saved token" aria-label="Logout">
                     <svg viewBox="0 0 24 24"><path d="M17 7l-1.41 1.41L18.17 11H8v2h10.17l-2.58 2.58L17 17l5-5zM4 5h8V3H4c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h8v-2H4V5z"/></svg>
                 </button>
             </div>

media_server/static/js/app.js

@@ -1368,6 +1368,13 @@
             currentState = status.state;
             updatePlaybackState(status.state);
 
+            // Update album art alt text for accessibility
+            const altText = status.title && status.artist
+                ? `${status.artist} – ${status.title}`
+                : status.title || t('player.no_media');
+            dom.albumArt.alt = altText;
+            dom.miniAlbumArt.alt = altText;
+
             // Update album art (skip if same track to avoid redundant network requests)
             const artworkSource = status.album_art_url || null;
             const artworkKey = `${status.title || ''}|${status.artist || ''}|${artworkSource || ''}`;
@@ -3468,7 +3475,16 @@ async function toggleDisplayPower(monitorId, monitorName) {
 // Header Quick Links
 // ============================================================
 
-const mdiIconCache = {};
+// In-memory + localStorage cache for MDI icons (persists across reloads)
+const mdiIconCache = (() => {
+    try {
+        return JSON.parse(localStorage.getItem('mdiIconCache') || '{}');
+    } catch { return {}; }
+})();
+
+function _persistMdiCache() {
+    try { localStorage.setItem('mdiIconCache', JSON.stringify(mdiIconCache)); } catch {}
+}
 
 async function fetchMdiIcon(iconName) {
     // Parse "mdi:icon-name" → "icon-name"
@@ -3480,6 +3496,7 @@ async function fetchMdiIcon(iconName) {
         if (response.ok) {
             const svg = await response.text();
             mdiIconCache[name] = svg;
+            _persistMdiCache();
             return svg;
         }
     } catch (e) {