diff --git a/src/components/session-chart.tsx b/src/components/session-chart.tsx
index 1922c49..860612f 100644
--- a/src/components/session-chart.tsx
+++ b/src/components/session-chart.tsx
@@ -123,7 +123,7 @@ export function ChartPlot({
 		[decimals, label, positions, unit, values]
 	);
 	return (
-		<div className={`flex w-full ${heightClass}`}>
+		<div className={`session-chart-plot flex w-full ${heightClass}`}>
 			<ChartScale decimals={decimals} maximum={maximum} minimum={minimum} unit={unit} />
 			<div className="relative h-full min-w-0 flex-1 overflow-hidden">
 				{showLabel ? (
diff --git a/src/style.css b/src/style.css
index 4a8fc6f..1c5c148 100644
--- a/src/style.css
+++ b/src/style.css
@@ -113,6 +113,27 @@ html[data-theme="light"] .session-chart[data-variant="session"] {
 	--chart-surface: #f3f3ef;
 }
 
+.session-chart-plot [data-chart-surface] {
+	position: relative;
+}
+
+.session-chart-plot [data-chart-surface]::after {
+	position: absolute;
+	inset: 0;
+	pointer-events: none;
+	content: "";
+	border-top: 1px solid var(--chart-grid);
+}
+
+.session-chart-plot:last-child [data-chart-surface]::after {
+	border-bottom: 1px solid var(--chart-grid);
+}
+
+.session-chart-plot [data-ts-key="horizontal-0"],
+.session-chart-plot [data-ts-key="horizontal-2"] {
+	display: none;
+}
+
 .ts-chart-host {
 	--ts-chart-focus-fill: var(--chart-surface);
 }