diff --git a/frontend/src/components/git/ForgejoHeatmap.tsx b/frontend/src/components/git/ForgejoHeatmap.tsx
index e1cc537..f389a62 100644
--- a/frontend/src/components/git/ForgejoHeatmap.tsx
+++ b/frontend/src/components/git/ForgejoHeatmap.tsx
@@ -129,16 +129,24 @@ function fmtCommitTitle(date: string, count: number): string {
 }
 
 // Catmull-Rom → cubic bezier smooth path
-function smoothPath(pts: { x: number; y: number }[]): string {
+function smoothPath(
+  pts: { x: number; y: number }[],
+  yMin?: number,
+  yMax?: number,
+): string {
   if (pts.length < 2) return "";
   const t = 1 / 6;
+  const cy = (y: number) =>
+    yMin !== undefined && yMax !== undefined
+      ? Math.max(yMin, Math.min(yMax, y))
+      : y;
   let d = `M${pts[0].x.toFixed(1)},${pts[0].y.toFixed(1)}`;
   for (let i = 0; i < pts.length - 1; i++) {
     const p0 = pts[Math.max(0, i - 1)],
       p1 = pts[i],
       p2 = pts[i + 1],
       p3 = pts[Math.min(pts.length - 1, i + 2)];
-    d += ` C${(p1.x + t * (p2.x - p0.x)).toFixed(1)},${(p1.y + t * (p2.y - p0.y)).toFixed(1)} ${(p2.x - t * (p3.x - p1.x)).toFixed(1)},${(p2.y - t * (p3.y - p1.y)).toFixed(1)} ${p2.x.toFixed(1)},${p2.y.toFixed(1)}`;
+    d += ` C${(p1.x + t * (p2.x - p0.x)).toFixed(1)},${cy(p1.y + t * (p2.y - p0.y)).toFixed(1)} ${(p2.x - t * (p3.x - p1.x)).toFixed(1)},${cy(p2.y - t * (p3.y - p1.y)).toFixed(1)} ${p2.x.toFixed(1)},${p2.y.toFixed(1)}`;
   }
   return d;
 }
@@ -274,7 +282,7 @@ function LineChart({
         };
       });
 
-      const linePath = smoothPath(pts);
+      const linePath = smoothPath(pts, LP_T, LP_T + LCH);
       const last = pts[pts.length - 1],
         first = pts[0];
       const baseline = LP_T + LCH;