fix gauge arc dasharray: use circ-seg_filled as gap, not full circ

app.py

@@ -1331,12 +1331,14 @@ def render_signal_gauge(value: int) -> str:
         if filled <= seg_start:
             break
         seg_filled = min(filled - seg_start, seg)
-        # rotate_deg: start at top (-90deg) then add segment offset
+        # Each arc: dasharray shows seg_filled px, hides the rest
+        # rotate so this segment starts at top (-90deg) + offset for prior segments
         rotate_deg = -90 + (seg_start / circ) * 360
         arc_elements.append(
             f'<circle cx="80" cy="80" r="68" fill="none" stroke="{color}" '
             f'stroke-width="7" stroke-linecap="round" '
-            f'stroke-dasharray="{seg_filled:.2f} {circ:.2f}" '
+            f'stroke-dasharray="{seg_filled:.2f} {(circ - seg_filled):.2f}" '
+            f'stroke-dashoffset="0" '
             f'transform="rotate({rotate_deg:.1f} 80 80)" />'
         )
     arcs_html = "\n        ".join(arc_elements)