Update css

Author: FloRobart

docs/css/custom.css

@@ -7,8 +7,16 @@
     --bs-link-hover-color-rgb: 114, 20, 20;
     --bs-primary: #721414;
     --bs-primary-rgb: 114, 20, 20;
+
+    --bs-primary-dark: #5B1010;
+    --bs-dropdown-link-active-bg: #5B1010;
+    --bs-dropdown-link-hover-bg: #5B1010;
 }
 
 .navbar.bg-primary {
-    background-image: linear-gradient(#5B1010,#5B1010);
+    background-image: linear-gradient(var(--bs-primary-dark), var(--bs-primary-dark));
+}
+
+.dropdown-item.open {
+    background-color: var(--bs-dropdown-link-active-bg);
 }