diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 8601be4..02dd261 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -3,7 +3,7 @@
 repos:
   # Ruff - fast Python linter
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.11.2
+    rev: v0.15.8
     hooks:
       - id: ruff
         args: [--fix, --exit-non-zero-on-fix]
@@ -11,10 +11,11 @@ repos:
 
   # Black - Python formatter
   - repo: https://github.com/psf/black
-    rev: 25.1.0
+    rev: 26.3.1
     hooks:
       - id: black
         files: ^(app|tests|scripts)/
+        language_version: python3.12
 
   # Type checking with mypy (optional, slower)
   # Uncomment to enable:
diff --git a/app/components/charts.py b/app/components/charts.py
index 41d945b..aef4fca 100644
--- a/app/components/charts.py
+++ b/app/components/charts.py
@@ -13,11 +13,9 @@ def _ensure_lightweight_charts_assets() -> None:
     global _CHARTS_SCRIPT_ADDED
     if _CHARTS_SCRIPT_ADDED:
         return
-    ui.add_head_html(
-        """
+    ui.add_head_html("""
         <script src="https://unpkg.com/lightweight-charts/dist/lightweight-charts.standalone.production.js"></script>
-        """
-    )
+        """)
     _CHARTS_SCRIPT_ADDED = True
 
 
@@ -48,8 +46,7 @@ class CandlestickChart:
         self._initialize_chart()
 
     def _initialize_chart(self) -> None:
-        ui.run_javascript(
-            f"""
+        ui.run_javascript(f"""
             (function() {{
                 const root = document.getElementById({json.dumps(self.chart_id)});
                 if (!root || typeof LightweightCharts === 'undefined') return;
@@ -94,57 +91,48 @@ class CandlestickChart:
                     indicators: {{}},
                 }};
             }})();
-            """
-        )
+            """)
 
     def set_candles(self, candles: list[dict[str, Any]]) -> None:
         payload = json.dumps(candles)
-        ui.run_javascript(
-            f"""
+        ui.run_javascript(f"""
             (function() {{
                 const ref = window.vaultDashCharts?.[{json.dumps(self.chart_id)}];
                 if (!ref) return;
                 ref.candleSeries.setData({payload});
                 ref.chart.timeScale().fitContent();
             }})();
-            """
-        )
+            """)
 
     def update_price(self, candle: dict[str, Any]) -> None:
         payload = json.dumps(candle)
-        ui.run_javascript(
-            f"""
+        ui.run_javascript(f"""
             (function() {{
                 const ref = window.vaultDashCharts?.[{json.dumps(self.chart_id)}];
                 if (!ref) return;
                 ref.candleSeries.update({payload});
             }})();
-            """
-        )
+            """)
 
     def set_volume(self, volume_points: list[dict[str, Any]]) -> None:
         payload = json.dumps(volume_points)
-        ui.run_javascript(
-            f"""
+        ui.run_javascript(f"""
             (function() {{
                 const ref = window.vaultDashCharts?.[{json.dumps(self.chart_id)}];
                 if (!ref) return;
                 ref.volumeSeries.setData({payload});
             }})();
-            """
-        )
+            """)
 
     def update_volume(self, volume_point: dict[str, Any]) -> None:
         payload = json.dumps(volume_point)
-        ui.run_javascript(
-            f"""
+        ui.run_javascript(f"""
             (function() {{
                 const ref = window.vaultDashCharts?.[{json.dumps(self.chart_id)}];
                 if (!ref) return;
                 ref.volumeSeries.update({payload});
             }})();
-            """
-        )
+            """)
 
     def set_indicator(
         self,
@@ -156,8 +144,7 @@ class CandlestickChart:
     ) -> None:
         key = json.dumps(name)
         payload = json.dumps(points)
-        ui.run_javascript(
-            f"""
+        ui.run_javascript(f"""
             (function() {{
                 const ref = window.vaultDashCharts?.[{json.dumps(self.chart_id)}];
                 if (!ref) return;
@@ -171,19 +158,16 @@ class CandlestickChart:
                 }}
                 ref.indicators[{key}].setData({payload});
             }})();
-            """
-        )
+            """)
 
     def update_indicator(self, name: str, point: dict[str, Any]) -> None:
         key = json.dumps(name)
         payload = json.dumps(point)
-        ui.run_javascript(
-            f"""
+        ui.run_javascript(f"""
             (function() {{
                 const ref = window.vaultDashCharts?.[{json.dumps(self.chart_id)}];
                 const series = ref?.indicators?.[{key}];
                 if (!series) return;
                 series.update({payload});
             }})();
-            """
-        )
+            """)
diff --git a/app/components/strategy_panel.py b/app/components/strategy_panel.py
index 35f66a3..e1cb165 100644
--- a/app/components/strategy_panel.py
+++ b/app/components/strategy_panel.py
@@ -117,8 +117,7 @@ class StrategyComparisonPanel:
             scenario_class = (
                 "text-emerald-600 dark:text-emerald-400" if scenario >= 0 else "text-rose-600 dark:text-rose-400"
             )
-            rows.append(
-                f"""
+            rows.append(f"""
                 <tr class=\"border-b border-slate-200 dark:border-slate-800\">
                     <td class=\"px-4 py-3 font-medium text-slate-900 dark:text-slate-100\">{name}</td>
                     <td class=\"px-4 py-3 text-slate-600 dark:text-slate-300\">${cost:,.2f}</td>
@@ -126,8 +125,7 @@ class StrategyComparisonPanel:
                     <td class=\"px-4 py-3 text-slate-600 dark:text-slate-300\">{self._format_cap(strategy)}</td>
                     <td class=\"px-4 py-3 font-semibold {scenario_class}\">${scenario:,.2f}</td>
                 </tr>
-                """
-            )
+                """)
         return f"""
         <div class=\"overflow-x-auto\">
             <table class=\"min-w-full rounded-xl overflow-hidden\">
diff --git a/app/pages/options.py b/app/pages/options.py
index 444a4cd..a2f81e0 100644
--- a/app/pages/options.py
+++ b/app/pages/options.py
@@ -137,8 +137,7 @@ async def options_page() -> None:
                     </thead>
                     <tbody>
             """
-                + "".join(
-                    f"""
+                + "".join(f"""
                         <tr class='border-b border-slate-200 dark:border-slate-800'>
                             <td class='px-4 py-3 font-medium text-slate-900 dark:text-slate-100'>{row['symbol']}</td>
                             <td class='px-4 py-3 text-slate-600 dark:text-slate-300'>{row['type'].upper()}</td>
@@ -149,9 +148,7 @@ async def options_page() -> None:
                             <td class='px-4 py-3 text-slate-600 dark:text-slate-300'>Δ {float(row.get('delta', 0.0)):+.3f} · Γ {float(row.get('gamma', 0.0)):.3f} · Θ {float(row.get('theta', 0.0)):+.3f} · V {float(row.get('vega', 0.0)):.3f}</td>
                             <td class='px-4 py-3 text-sky-600 dark:text-sky-300'>Use quick-add buttons below</td>
                         </tr>
-                """
-                    for row in rows
-                )
+                """ for row in rows)
                 + (
                     ""
                     if rows
diff --git a/app/pages/overview.py b/app/pages/overview.py
index 666881f..7b3e0fb 100644
--- a/app/pages/overview.py
+++ b/app/pages/overview.py
@@ -124,13 +124,11 @@ def welcome_page(request: Request):
                     if turnstile.uses_test_keys
                     else ""
                 )
-                ui.html(
-                    f"""<form method="post" action="/workspaces/bootstrap" class="flex items-center gap-4">
+                ui.html(f"""<form method="post" action="/workspaces/bootstrap" class="flex items-center gap-4">
                         {hidden_token}
                         <div class="cf-turnstile" data-sitekey="{turnstile.site_key}"></div>
                         <button type="submit" class="rounded-lg bg-slate-900 px-5 py-3 text-sm font-semibold text-white no-underline dark:bg-slate-100 dark:text-slate-900">Get started</button>
-                    </form>"""
-                )
+                    </form>""")
                 ui.label("You can always create a fresh workspace later if a link is lost.").classes(
                     "text-sm text-slate-500 dark:text-slate-400"
                 )
diff --git a/requirements-dev.txt b/requirements-dev.txt
index 4759ae5..acdf6f8 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -2,7 +2,7 @@
 
 pytest>=8.0.0
 pytest-asyncio>=0.23.0
-black>=24.0.0
+black==26.3.1
 ruff>=0.2.0
 mypy>=1.8.0
 types-requests>=2.31.0
diff --git a/tests/test_overview_ltv_history_playwright.py b/tests/test_overview_ltv_history_playwright.py
index 54caf26..2a6d4a8 100644
--- a/tests/test_overview_ltv_history_playwright.py
+++ b/tests/test_overview_ltv_history_playwright.py
@@ -26,16 +26,14 @@ def test_overview_shows_ltv_history_and_exports_csv() -> None:
         expect(page.locator("text=90 Day").first).to_be_visible(timeout=15000)
         expect(page.get_by_role("button", name="Export CSV")).to_be_visible(timeout=15000)
 
-        series_names = page.evaluate(
-            """
+        series_names = page.evaluate("""
             async () => {
               const importMap = JSON.parse(document.querySelector('script[type="importmap"]').textContent).imports;
               const mod = await import(importMap['nicegui-echart']);
               const chart = mod.echarts.getInstanceByDom(document.querySelector('.nicegui-echart'));
               return chart ? chart.getOption().series.map(series => series.name) : [];
             }
-            """
-        )
+            """)
         assert series_names == ["LTV", "Margin threshold"]
 
         with page.expect_download() as download_info: