refactor: Drop top border on main container on mobile

Signed-off-by: Felicitas Pojtinger <felicitas@pojtinger.com>

Author: pojntfx

assets/scss/main.scss

@@ -408,6 +408,12 @@ $font-path: "../../webfonts";
   --pf-v6-c-page__main-container--BorderBlockEndWidth: 0;
 }
 
+.pf-v6-c-drawer__content.pf-v6-c-page__main-container {
+  @media screen and (max-width: calc(#{$pf-v6-global--breakpoint--md} - 1px)) {
+    border-block-start-width: 0;
+  }
+}
+
 // On the home page, only remove the right margin when the Mastodon feed sidebar is visible
 .pf-v6-c-drawer__content.pf-v6-c-page__main-container {
   @media screen and (min-width: $pf-v6-global--breakpoint--xl) {