fix(components): remove transform property from scroll-locked parent (#4957)

Author: oliverschuerch

.changeset/moody-mice-design.md

@@ -0,0 +1,6 @@
+---
+'@swisspost/design-system-components': patch
+'@swisspost/design-system-styles': patch
+---
+
+Removed the `transform` property from the scroll-locked `post-header` parent, to avoid side effects. Updated the mobile menu of the `post-header`, so it works as before.

packages/components/src/components/post-header/post-header.scss

@@ -207,10 +207,10 @@
 // only for tablet and mobile
 @include media.max(lg) {
   .navigation {
-    position: fixed;
+    position: sticky;
     z-index: 1;
     inset-inline: 0;
-    inset-block-start: calc(var(--header-scroll-top) + var(--header-height));
+    inset-block-start: var(--header-height);
   }
 
   .mobile-menu {

packages/styles/src/components/header/index.scss

@@ -10,7 +10,6 @@ tokens.$default-map: elements.$post-link;
 
 [data-post-scroll-locked] {
   overflow: hidden !important;
-  transform: translate3d(0, 0, 0) !important;
 }
 
 post-header {