add css (#88)

Author: cloutierMat

src/styles/custom.css

@@ -280,4 +280,12 @@ h2#starlight__on-this-page::before {
 
 .right-sidebar-panel:where(.astro-pb3aqygn) :where(a) {
     font-size: 14px;
+}
+
+.sidebar-pane {
+    scrollbar-gutter: stable;
+}
+
+.sidebar-pane .sidebar-content {
+    padding-right: 0;
 }