diff --git a/layers/components/atoms/Input.vue b/layers/components/atoms/Input.vue
index a80f637..7ad4980 100644
--- a/layers/components/atoms/Input.vue
+++ b/layers/components/atoms/Input.vue
@@ -37,7 +37,7 @@ const onInput = (event: Event) => {
       :type="typeof $attrs.type === 'string' ? $attrs.type : 'text'"
       :placeholder="props.placeholder"
       v-bind="$attrs"
-      class="relative w-full h-[48px] px-[12px] outline-none border border-solid border-[1px] border-[#D9D9D9] rounded-[8px] bg-white text-left text-[#333333] text-[14px] font-[400] leading-[20px] tracking-[-0.42px] placeholder:text-[#B2B2B2] md:h-[56px] md:px-[16px] md:text-[16px] md:leading-[26px] md:tracking-[-0.48px] hover:[&:not([readonly])]:border-[#999999] focus:border-[#999999]"
+      class="relative w-full h-[48px] px-[12px] outline-none border-solid border-[1px] border-[#D9D9D9] rounded-[8px] bg-white text-left text-[#333333] text-[14px] font-[400] leading-[20px] tracking-[-0.42px] placeholder:text-[#B2B2B2] md:h-[56px] md:px-[16px] md:text-[16px] md:leading-[26px] md:tracking-[-0.48px] hover:[&:not([readonly])]:border-[#999999] focus:border-[#999999]"
       @input="onInput"
       @keydown="emit('keydown', $event)"
     />
diff --git a/layers/components/blocks/Button/Sns.vue b/layers/components/blocks/Button/Sns.vue
index a1aaa5d..cabbce1 100644
--- a/layers/components/blocks/Button/Sns.vue
+++ b/layers/components/blocks/Button/Sns.vue
@@ -1,6 +1,7 @@
 <script setup lang="ts">
 const showSnsList = ref(false)
 
+const { tm } = useI18n()
 const gameDataStore = useGameDataStore()
 const modalStore = useModalStore()
 
@@ -33,9 +34,9 @@ const handleCopy = async () => {
   try {
     const url = window.location.href
     await navigator.clipboard.writeText(url)
-    handleOpenToast('복사 성공')
+    handleOpenToast(tm('Alert_Copy_Complete'))
   } catch (error) {
-    console.error('복사 실패:', error)
+    console.error('[handleCopy] Error:', error)
   }
 }
 </script>
diff --git a/layers/components/blocks/modal/Toast.vue b/layers/components/blocks/modal/Toast.vue
index 3663e1e..7589c78 100644
--- a/layers/components/blocks/modal/Toast.vue
+++ b/layers/components/blocks/modal/Toast.vue
@@ -6,9 +6,7 @@ const { toast } = modalStore
 <template>
   <Transition name="fade">
     <div v-if="toast.storeIsOpen" class="toast-container">
-      <p class="toast-text">
-        {{ toast.storeContentText }}
-      </p>
+      <p v-dompurify-html="toast.storeContentText" class="toast-text"></p>
     </div>
   </Transition>
 </template>
diff --git a/layers/components/layouts/Header.vue b/layers/components/layouts/Header.vue
index e2391af..1490ca0 100644
--- a/layers/components/layouts/Header.vue
+++ b/layers/components/layouts/Header.vue
@@ -52,11 +52,11 @@ const hasActiveChild = (children?: GameDataMenuChildren) => {
 const isNavItemActive = (gnbItem: GameDataMenu): boolean => {
   const cur = currentPath.value
   const base = gnbItem?.url_path
-  if(import.meta.client) {
+  if (import.meta.client) {
     const selfActive =
-        !!base &&
-        isInternalUrl(base) &&
-        pathMatches(formatPathWithoutLocale(base), cur)
+      !!base &&
+      isInternalUrl(base) &&
+      pathMatches(formatPathWithoutLocale(base), cur)
     return selfActive || hasActiveChild(gnbItem.children)
   }
 }
@@ -363,7 +363,7 @@ onBeforeUnmount(() => {
 
 <style scoped>
 .header {
-  @apply bg-theme-foreground text-theme-foreground-reversal relative z-[100];
+  @apply bg-theme-foreground text-theme-foreground-reversal relative z-[200];
 }
 .game-wrap {
   @apply absolute flex w-full h-[48px] items-center whitespace-nowrap px-[52px] bg-theme-foreground sm:px-[72px] md:h-16 md:pl-0 md:pr-[40px]
diff --git a/layers/composables/useGameStart.ts b/layers/composables/useGameStart.ts
index 646727d..e4aff9a 100644
--- a/layers/composables/useGameStart.ts
+++ b/layers/composables/useGameStart.ts
@@ -83,9 +83,18 @@ export const useCheckGameStart = () => {
     }
   }
 
+  // OS 체크 함수 추가
+  const checkWindowsOS = (): boolean => {
+    // 서버 사이드 렌더링 중에는 navigator 객체가 없으므로, 항상 false를 반환하여 통과시킵니다.
+    // 실제 OS 체크는 클라이언트 사이드에서만 의미가 있습니다.
+    if (typeof navigator === 'undefined') {
+      return false
+    }
+    return /windows/i.test(navigator.userAgent)
+  }
+
   // 런처 호출
   const runLauncher = async () => {
-    // 클라이언트에서만 실행
     if (!import.meta.client) return
 
     const gameDataStore = useGameDataStore()
@@ -141,6 +150,14 @@ export const useCheckGameStart = () => {
   const validateLauncher = () => {
     if (isProcessing.value) return
 
+    const isWindowsOS = checkWindowsOS()
+    if (!isWindowsOS) {
+      modalStore.handleOpenAlert({
+        contentText: tm('Alert_Client_Window'),
+      })
+      return
+    }
+
     isProcessing.value = true
     debounceHandler()
   }