feat: add sysfs serial fallback for RAID disks and responsive disk grid layout with improved styling

Add _device_serial() to read disk serials from /sys/class/block/{name}/device/serial and /sys/block/{name}/device/serial when lsblk cannot expose them in Docker containers. Update raid_status() to use sysfs fallback before defaulting to "—" for missing serials. Add .raid-disks 2-column grid with 6px gap, .raid-disk 7px/9px padding, .raid-disk small 1px top margin, and .raid-smart 85% opacity. Add mobile

app.py

@@ -240,6 +240,18 @@ def _flatten_lsblk(nodes):
         result.extend(_flatten_lsblk(node.get("children")))
     return result
 
+def _device_serial(device):
+    """Read a disk serial from sysfs when lsblk cannot expose it in Docker."""
+    name = Path(device).name
+    for path in (Path("/sys/class/block") / name / "device/serial", Path("/sys/block") / name / "device/serial"):
+        try:
+            value = path.read_text().strip()
+            if value:
+                return value
+        except OSError:
+            continue
+    return ""
+
 def format_transfer_rate(value):
     """Convert mdstat rates such as 133628K/sec into a readable value."""
     if not value or value == "—":
@@ -340,7 +352,8 @@ def raid_status():
                 info = host_items[0] if host_items else {}
             except (ValueError, AttributeError):
                 info = {}
-        disk.update({"size": format_bytes(info.get("size") or 0) if info.get("size") else "—", "model": info.get("model") or "—", "serial": info.get("serial") or "—"})
+        serial = info.get("serial") or _device_serial(disk["device"])
+        disk.update({"size": format_bytes(info.get("size") or 0) if info.get("size") else "—", "model": info.get("model") or "—", "serial": serial or "—"})
         if SMART_ENABLED and shutil.which("smartctl"):
             smart_device = disk["device"].replace("/dev/", f"{HOST_DEVICE_PATH.rstrip('/')}/", 1)
             smart_output, _ = _read_command(["smartctl", "-H", smart_device], timeout=6)