Fix main content negative margin for viewports in [$md, $nav-width + $content-width] (#1177)

_sass/layout.scss

@@ -29,9 +29,13 @@
   }
 
   @include mq(lg) {
-    margin-left: calc(
+    // stylelint-disable function-name-case
-      (100% - #{$nav-width + $content-width}) / 2 + #{$nav-width}
+    // disable for Max(), we want to use the CSS max() function
+    margin-left: Max(
+      #{$nav-width},
+      calc((100% - #{$nav-width + $content-width}) / 2 + #{$nav-width})
     );
+    // stylelint-enable function-name-case
   }
 }