add some custom css styles for better html formatting

Handbook/styles/custom.css

@@ -0,0 +1,11 @@
+:root {
+    --content-max-width: 1280px;
+}
+
+#sidebar-toggle-anchor:checked ~ .page-wrapper .nav-wide-wrapper {
+    display: none !important;
+}
+
+#sidebar-toggle-anchor:checked ~ .page-wrapper .nav-wrapper {
+    display: block !important;
+}