Bumps header font for better readability

src/webviews/apps/plus/graph/graph.scss

@@ -512,6 +512,7 @@ a {
 }
 
 .graph-app {
+	--fs-1: 1.1rem;
 	--fs-2: 1.3rem;
 	--scroll-thumb-bg: var(--vscode-scrollbarSlider-background);