diff --git a/src/routes/dialog/index.svelte b/src/routes/dialog/index.svelte
index aa9fd71..7a4a060 100644
--- a/src/routes/dialog/index.svelte
+++ b/src/routes/dialog/index.svelte
@@ -21,7 +21,7 @@
     modifiers: [{ name: "offset", options: { offset: [0, 10] } }],
   };
 
-  function classNames(...classes: unknown[]) {
+  function classNames(...classes: (string | false | null | undefined)[]) {
     return classes.filter(Boolean).join(" ");
   }
 
diff --git a/src/routes/listbox/_PeopleList.svelte b/src/routes/listbox/_PeopleList.svelte
index c4b1c71..cfe314e 100644
--- a/src/routes/listbox/_PeopleList.svelte
+++ b/src/routes/listbox/_PeopleList.svelte
@@ -7,7 +7,7 @@
     ListboxOptions,
   } from "$lib";
 
-  function classNames(...classes) {
+  function classNames(...classes: (string | false | null | undefined)[]) {
     return classes.filter(Boolean).join(" ");
   }
 
diff --git a/src/routes/menu/menu-with-transition.svelte b/src/routes/menu/menu-with-transition.svelte
index e54a1f0..b444716 100644
--- a/src/routes/menu/menu-with-transition.svelte
+++ b/src/routes/menu/menu-with-transition.svelte
@@ -1,7 +1,7 @@
 <script lang="ts">
   import { Menu, MenuButton, MenuItem, MenuItems, Transition } from "$lib";
 
-  function classNames(...classes) {
+  function classNames(...classes: (string | false | null | undefined)[]) {
     return classes.filter(Boolean).join(" ");
   }
   function resolveClass({ active, disabled }) {
diff --git a/src/routes/radio-group/radio-group.svelte b/src/routes/radio-group/radio-group.svelte
index 7ab9146..229bc09 100644
--- a/src/routes/radio-group/radio-group.svelte
+++ b/src/routes/radio-group/radio-group.svelte
@@ -1,6 +1,6 @@
 <script lang="ts">
   import { RadioGroup, RadioGroupOption } from "$lib";
-  function classNames(...classes) {
+  function classNames(...classes: (string | false | null | undefined)[]) {
     return classes.filter(Boolean).join(" ");
   }
   let access = [
diff --git a/src/routes/switch/switch-with-pure-tailwind.svelte b/src/routes/switch/switch-with-pure-tailwind.svelte
index 3513655..e3499ae 100644
--- a/src/routes/switch/switch-with-pure-tailwind.svelte
+++ b/src/routes/switch/switch-with-pure-tailwind.svelte
@@ -1,7 +1,7 @@
 <script lang="ts">
   import { Switch, SwitchGroup, SwitchLabel } from "$lib";
 
-  function classNames(...classes) {
+  function classNames(...classes: (string | false | null | undefined)[]) {
     return classes.filter(Boolean).join(" ");
   }
 
diff --git a/src/routes/tabs/tabs-with-pure-tailwind.svelte b/src/routes/tabs/tabs-with-pure-tailwind.svelte
index 7ef3d05..dda5d0a 100644
--- a/src/routes/tabs/tabs-with-pure-tailwind.svelte
+++ b/src/routes/tabs/tabs-with-pure-tailwind.svelte
@@ -10,7 +10,7 @@
     TabPanels,
   } from "$lib";
 
-  function classNames(...classes) {
+  function classNames(...classes: (string | false | null | undefined)[]) {
     return classes.filter(Boolean).join(" ");
   }