ISTWCMS-5898: section-spacing-seperator and column-seperator css

ISTWCMS-5898: Adding the bottom lines when narrow and adjusting spacing in cards: event news blog and web page

src/patterns/03-layouts/site-container/_site-container.scss

@@ -14,6 +14,11 @@
     z-index: var(--layer-header);
   }
   .uw-highlighted {
+    @include uw-contained-width(var(--layout-max-width-narrow));
+    @media(min-width: $screen-xl) {
+      // Reset the width so we use all the width when we have room to.
+      @include uw-contained-width(var(--layout-max-width));
+    }
     grid-column: 1 / 2;
     grid-row: 2 / 3;
     position: relative;