diff --git a/fusion_accounting_reports/__manifest__.py b/fusion_accounting_reports/__manifest__.py
index 2f5f7e14..d50fcbd1 100644
--- a/fusion_accounting_reports/__manifest__.py
+++ b/fusion_accounting_reports/__manifest__.py
@@ -1,6 +1,6 @@
 {
     'name': 'Fusion Accounting Reports',
-    'version': '19.0.1.0.1',
+    'version': '19.0.1.0.2',
     'category': 'Accounting/Accounting',
     'summary': 'AI-augmented financial reports (P&L, balance sheet, trial balance, GL).',
     'description': """
diff --git a/fusion_accounting_reports/services/__init__.py b/fusion_accounting_reports/services/__init__.py
index 5fc930af..91a1820c 100644
--- a/fusion_accounting_reports/services/__init__.py
+++ b/fusion_accounting_reports/services/__init__.py
@@ -2,3 +2,4 @@ from . import date_periods
 from . import account_hierarchy
 from . import totaling
 from . import currency_conversion
+from . import line_resolver
diff --git a/fusion_accounting_reports/services/line_resolver.py b/fusion_accounting_reports/services/line_resolver.py
new file mode 100644
index 00000000..4dc433b9
--- /dev/null
+++ b/fusion_accounting_reports/services/line_resolver.py
@@ -0,0 +1,143 @@
+"""Resolve a fusion.report definition into report rows.
+
+Pure-Python: takes line_specs (list of dicts), a period, and aggregated
+move-line data (per-account totals) - returns ordered list of report row
+dicts ready for the OWL frontend or PDF rendering.
+
+Row shape:
+{
+  'id': 'line_<index>',
+  'label': str,
+  'level': int,                  # indentation depth
+  'is_subtotal': bool,
+  'amount': float,
+  'amount_comparison': float | None,
+  'variance_pct': float | None,
+  'account_id': int | None,      # for drill-down (None for subtotals)
+  'children': list[dict],         # populated when expanded
+}"""
+
+from dataclasses import dataclass
+
+from .totaling import TotalLine
+
+
+@dataclass
+class ReportRow:
+    id: str
+    label: str
+    level: int = 0
+    is_subtotal: bool = False
+    amount: float = 0.0
+    amount_comparison: float | None = None
+    variance_pct: float | None = None
+    account_id: int | None = None
+
+    def to_dict(self):
+        return {
+            'id': self.id,
+            'label': self.label,
+            'level': self.level,
+            'is_subtotal': self.is_subtotal,
+            'amount': self.amount,
+            'amount_comparison': self.amount_comparison,
+            'variance_pct': self.variance_pct,
+            'account_id': self.account_id,
+        }
+
+
+def resolve(
+    line_specs: list[dict],
+    *,
+    account_totals: dict[int, TotalLine],
+    accounts_by_id: dict[int, dict],
+    comparison_totals: dict[int, TotalLine] | None = None,
+) -> list[dict]:
+    """Resolve line_specs against actual account totals -> list of row dicts.
+
+    Args:
+        line_specs: report definition line specs (from fusion.report.line_specs).
+        account_totals: {account_id: TotalLine} for the period.
+        accounts_by_id: {account_id: {code, name, account_type, ...}}.
+        comparison_totals: optional {account_id: TotalLine} for comparison period.
+
+    Returns: list of row dicts."""
+    rows: list[ReportRow] = []
+
+    for idx, spec in enumerate(line_specs):
+        if spec.get('compute') == 'subtotal':
+            n = spec.get('above', 1)
+            sign = spec.get('sign', 1)
+            recent = [r.amount for r in rows[-n:] if not r.is_subtotal]
+            row = ReportRow(
+                id=f'line_{idx}',
+                label=spec.get('label', 'Subtotal'),
+                level=spec.get('level', 0),
+                is_subtotal=True,
+                amount=sum(recent) * sign,
+            )
+            if comparison_totals is not None:
+                comp_recent = [
+                    r.amount_comparison
+                    for r in rows[-n:]
+                    if not r.is_subtotal and r.amount_comparison is not None
+                ]
+                row.amount_comparison = (
+                    sum(comp_recent) * sign if comp_recent else None
+                )
+            rows.append(row)
+
+        elif spec.get('account_type_prefix'):
+            prefix = spec['account_type_prefix']
+            sign = spec.get('sign', 1)
+            matched_ids = [
+                aid for aid, info in accounts_by_id.items()
+                if info.get('account_type', '').startswith(prefix)
+            ]
+            amount = sum(
+                account_totals.get(aid, TotalLine()).balance * sign
+                for aid in matched_ids
+            )
+            row = ReportRow(
+                id=f'line_{idx}',
+                label=spec.get('label', prefix),
+                level=spec.get('level', 0),
+                amount=amount,
+            )
+            if comparison_totals is not None:
+                comp_amount = sum(
+                    comparison_totals.get(aid, TotalLine()).balance * sign
+                    for aid in matched_ids
+                )
+                row.amount_comparison = comp_amount
+                if comp_amount != 0:
+                    row.variance_pct = (
+                        (amount - comp_amount) / abs(comp_amount)
+                    ) * 100
+            rows.append(row)
+
+        elif spec.get('account_id'):
+            aid = spec['account_id']
+            sign = spec.get('sign', 1)
+            tot = account_totals.get(aid, TotalLine())
+            label = spec.get('label') or accounts_by_id.get(aid, {}).get(
+                'name', f'Account {aid}'
+            )
+            row = ReportRow(
+                id=f'line_{idx}',
+                label=label,
+                level=spec.get('level', 0),
+                amount=tot.balance * sign,
+                account_id=aid,
+            )
+            if comparison_totals is not None:
+                comp = comparison_totals.get(aid, TotalLine())
+                row.amount_comparison = comp.balance * sign
+                if row.amount_comparison and row.amount_comparison != 0:
+                    row.variance_pct = (
+                        (row.amount - row.amount_comparison)
+                        / abs(row.amount_comparison)
+                    ) * 100
+            rows.append(row)
+
+    return [r.to_dict() for r in rows]
diff --git a/fusion_accounting_reports/tests/__init__.py b/fusion_accounting_reports/tests/__init__.py
index 70e2fc6e..92f4dac3 100644
--- a/fusion_accounting_reports/tests/__init__.py
+++ b/fusion_accounting_reports/tests/__init__.py
@@ -1,3 +1,4 @@
 from . import test_services_unit
 from . import test_currency_conversion
 from . import test_fusion_report
+from . import test_line_resolver
diff --git a/fusion_accounting_reports/tests/test_line_resolver.py b/fusion_accounting_reports/tests/test_line_resolver.py
new file mode 100644
index 00000000..0c35430f
--- /dev/null
+++ b/fusion_accounting_reports/tests/test_line_resolver.py
@@ -0,0 +1,96 @@
+"""Tests for line_resolver."""
+
+from odoo.tests.common import TransactionCase, tagged
+from odoo.addons.fusion_accounting_reports.services.line_resolver import resolve
+from odoo.addons.fusion_accounting_reports.services.totaling import TotalLine
+
+
+@tagged('post_install', '-at_install')
+class TestLineResolver(TransactionCase):
+
+    def test_resolve_account_type_prefix(self):
+        line_specs = [
+            {'label': 'Revenue', 'account_type_prefix': 'income_', 'sign': 1},
+        ]
+        accounts_by_id = {
+            1: {'code': '4000', 'name': 'Sales', 'account_type': 'income_other'},
+            2: {'code': '4100', 'name': 'Service Revenue', 'account_type': 'income_service'},
+            3: {'code': '5000', 'name': 'COGS', 'account_type': 'expense_direct_cost'},
+        }
+        account_totals = {
+            1: TotalLine(balance=10000),
+            2: TotalLine(balance=5000),
+            3: TotalLine(balance=4000),
+        }
+        rows = resolve(
+            line_specs,
+            account_totals=account_totals,
+            accounts_by_id=accounts_by_id,
+        )
+        self.assertEqual(len(rows), 1)
+        self.assertEqual(rows[0]['label'], 'Revenue')
+        self.assertEqual(rows[0]['amount'], 15000)
+
+    def test_resolve_subtotal(self):
+        line_specs = [
+            {'label': 'Revenue', 'account_type_prefix': 'income_', 'sign': 1},
+            {'label': 'COGS', 'account_type_prefix': 'expense_', 'sign': -1},
+            {'label': 'Gross Profit', 'compute': 'subtotal', 'above': 2},
+        ]
+        accounts_by_id = {
+            1: {'code': '4000', 'name': 'Sales', 'account_type': 'income_other'},
+            2: {'code': '5000', 'name': 'COGS', 'account_type': 'expense_direct'},
+        }
+        account_totals = {
+            1: TotalLine(balance=10000),
+            2: TotalLine(balance=4000),
+        }
+        rows = resolve(
+            line_specs,
+            account_totals=account_totals,
+            accounts_by_id=accounts_by_id,
+        )
+        self.assertEqual(len(rows), 3)
+        self.assertEqual(rows[0]['amount'], 10000)
+        self.assertEqual(rows[1]['amount'], -4000)
+        self.assertEqual(rows[2]['amount'], 6000)
+        self.assertTrue(rows[2]['is_subtotal'])
+
+    def test_resolve_with_comparison(self):
+        line_specs = [
+            {'label': 'Revenue', 'account_type_prefix': 'income_', 'sign': 1},
+        ]
+        accounts_by_id = {
+            1: {'code': '4000', 'name': 'Sales', 'account_type': 'income_other'},
+        }
+        account_totals = {1: TotalLine(balance=12000)}
+        comparison_totals = {1: TotalLine(balance=10000)}
+        rows = resolve(
+            line_specs,
+            account_totals=account_totals,
+            accounts_by_id=accounts_by_id,
+            comparison_totals=comparison_totals,
+        )
+        self.assertEqual(rows[0]['amount'], 12000)
+        self.assertEqual(rows[0]['amount_comparison'], 10000)
+        self.assertAlmostEqual(rows[0]['variance_pct'], 20.0)
+
+    def test_resolve_empty_specs(self):
+        rows = resolve([], account_totals={}, accounts_by_id={})
+        self.assertEqual(rows, [])
+
+    def test_resolve_account_id_drill_down(self):
+        line_specs = [
+            {'label': 'Cash', 'account_id': 99, 'sign': 1},
+        ]
+        accounts_by_id = {
+            99: {'code': '1100', 'name': 'Cash', 'account_type': 'asset_cash'},
+        }
+        account_totals = {99: TotalLine(balance=5000)}
+        rows = resolve(
+            line_specs,
+            account_totals=account_totals,
+            accounts_by_id=accounts_by_id,
+        )
+        self.assertEqual(rows[0]['account_id'], 99)
+        self.assertEqual(rows[0]['amount'], 5000)