diff --git a/.changeset/nervous-lizards-laugh.md b/.changeset/nervous-lizards-laugh.md
new file mode 100644
index 0000000000..944f941bc9
--- /dev/null
+++ b/.changeset/nervous-lizards-laugh.md
@@ -0,0 +1,5 @@
+---
+'@swisspost/design-system-styles': minor
+---
+
+Removed outdated portal-specific styles, including subnavigation-related rules.
diff --git a/packages/styles/src/index.scss b/packages/styles/src/index.scss
index 97fa256ba6..2f92769c20 100644
--- a/packages/styles/src/index.scss
+++ b/packages/styles/src/index.scss
@@ -4,6 +4,3 @@
 @use './utilities';
 @use './elements';
 @use './components';
-
-// Portal specific styles
-@use './layouts/portal';
diff --git a/packages/styles/src/layouts/portal/_index.scss b/packages/styles/src/layouts/portal/_index.scss
deleted file mode 100644
index c067e7178e..0000000000
--- a/packages/styles/src/layouts/portal/_index.scss
+++ /dev/null
@@ -1 +0,0 @@
-@use './subnavigation';
diff --git a/packages/styles/src/layouts/portal/_subnavigation.scss b/packages/styles/src/layouts/portal/_subnavigation.scss
deleted file mode 100644
index 538ea92584..0000000000
--- a/packages/styles/src/layouts/portal/_subnavigation.scss
+++ /dev/null
@@ -1,5 +0,0 @@
-.subnavigation-list {
-  width: 100%;
-  margin: 0;
-  padding: 0;
-}
diff --git a/packages/styles/tests/layouts/portal/index.test.scss b/packages/styles/tests/layouts/portal/index.test.scss
deleted file mode 100644
index 477d1c3bf2..0000000000
--- a/packages/styles/tests/layouts/portal/index.test.scss
+++ /dev/null
@@ -1 +0,0 @@
-@use 'src/layouts/portal';