Update setup.scss

Author: KristinaYFischer

docs/_sass/custom/setup.scss

@@ -96,13 +96,13 @@ $border-color: $grey-lt-100 !default;
 
 $gutter-spacing: $sp-6 !default;
 $gutter-spacing-sm: $sp-4 !default;
-$nav-width: 12rem;
-$nav-width-md: 11.5rem;
+$nav-width: 10rem;
+$nav-width-md: 9.5rem;
 $nav-list-item-height: $sp-6 !default;
 $nav-list-item-height-sm: $sp-8 !default;
 $nav-list-expander-right: true;
 $content-width: 50rem !default;
-$header-height: 5rem;
+$header-height: 8rem;
 $search-results-width: $content-width - $nav-width !default;
 $transition-duration: 400ms;