fix: anchor hedge contribution bars at zero

app/pages/hedge.py

@@ -33,19 +33,8 @@ def _cost_benefit_options(metrics: dict) -> dict:
 
 def _waterfall_options(metrics: dict) -> dict:
     steps = metrics["waterfall_steps"]
-    running = 0.0
-    base: list[float] = []
     values: list[dict[str, object]] = []
-    for index, (label, amount) in enumerate(steps):
-        if index == 0:
-            base.append(0)
-            running = amount
-        elif index == len(steps) - 1:
-            base.append(0)
-        else:
-            base.append(running)
-            running += amount
-
+    for label, amount in steps:
         color = "#0ea5e9" if label == "Net equity" else ("#22c55e" if amount >= 0 else "#ef4444")
         values.append({"value": amount, "itemStyle": {"color": color}})
 
@@ -56,14 +45,6 @@ def _waterfall_options(metrics: dict) -> dict:
         "series": [
             {
                 "type": "bar",
-                "stack": "total",
-                "data": base,
-                "itemStyle": {"color": "rgba(0,0,0,0)"},
-                "tooltip": {"show": False},
-            },
-            {
-                "type": "bar",
-                "stack": "total",
                 "data": values,
             },
         ],

tests/test_hedge_metrics.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from app.pages.common import strategy_metrics
+from app.pages.hedge import _waterfall_options
 
 
 def test_protective_put_atm_minus_20pct_improves_equity() -> None:
@@ -18,3 +19,13 @@ def test_protective_put_atm_minus_20pct_improves_equity() -> None:
         ("Hedge cost", -6_250.0),
         ("Net equity", 58_750.0),
     ]
+
+
+def test_hedge_waterfall_uses_zero_based_contribution_bars() -> None:
+    options = _waterfall_options(strategy_metrics("protective_put_atm", -20))
+
+    assert len(options["series"]) == 1
+    assert options["series"][0]["type"] == "bar"
+    values = options["series"][0]["data"]
+    assert values[2]["value"] == 38_000.0
+    assert values[2]["itemStyle"]["color"] == "#22c55e"