Update dropdown menu styles

Author: datakurre

frontend/packages/volto-ploneconf-core/news/20.feature

@@ -0,0 +1 @@
+Update dropdown menu styles @rioksane

frontend/packages/volto-ploneconf-core/src/theme/components/_navigation.scss

@@ -2,3 +2,20 @@
 .navigation .item:hover::before {
   border-bottom: 9px solid var(--secondary-color, #000);
 }
+.navigation ul.desktop-menu .submenu-inner h2 {
+  font-weight: 600;
+  border-bottom: 1px solid;
+}
+
+.navigation ul.desktop-menu .submenu-inner .subitem-wrapper {
+  border-left: none;
+}
+
+.navigation ul.desktop-menu .submenu a span {
+  border-bottom: 1px solid;
+}
+
+.navigation ul.desktop-menu .submenu a span:hover,
+.navigation ul.desktop-menu .submenu-inner h2:hover {
+  border-bottom: none;
+}