diff --git a/packages/frontend/src/Layout.vue b/packages/frontend/src/Layout.vue
index 60a7c8b..3dc3116 100755
--- a/packages/frontend/src/Layout.vue
+++ b/packages/frontend/src/Layout.vue
@@ -18,7 +18,7 @@
           : ""'
         title="ホーム"
       >
-        <img :src='"icon" in serverInfo && serverInfo.icon
+        <img :src='serverInfo && "icon" in serverInfo && serverInfo.icon
           ? serverInfo.icon
           : "/assets/lynqchat.svg"'
         />
@@ -56,7 +56,7 @@
       <div class="content-header">
         {{
           title
-            ?? (serverInfo.success
+            ?? (serverInfo?.success
               ? serverInfo.name
               : null)
             ?? "LynqChat"
@@ -261,7 +261,7 @@ watch(route, () => {
     title.value = route.meta.title;
 });
 
-if (!serverInfo.value.success) {
+if (!serverInfo.value?.success) {
   throw new Error("サーバー情報の取得に失敗しました。");
 }
 
@@ -294,6 +294,24 @@ function handleError(event: ErrorEvent | PromiseRejectionEvent) {
 onMounted(async () => {
   window.addEventListener("error", handleError);
   window.addEventListener("unhandledrejection", handleError);
+
+  if ("serviceWorker" in navigator) {
+    try {
+      const swFile = import.meta.env.MODE === "production"
+        ? "/sw.js"
+        : "/dev-sw.js?dev-sw";
+      const registration = await navigator.serviceWorker.register(swFile, {
+        updateViaCache: "none",
+        type: import.meta.env.MODE === "production"
+          ? "classic"
+          : "module",
+        scope: "/",
+      });
+      await registration.update();
+    } catch (err) {
+      console.error("Service Worker registration failed:", err);
+    }
+  }
 });
 
 onBeforeUnmount(() => {
diff --git a/packages/frontend/src/lib/account.ts b/packages/frontend/src/lib/account.ts
index a04dc51..71ed415 100644
--- a/packages/frontend/src/lib/account.ts
+++ b/packages/frontend/src/lib/account.ts
@@ -4,8 +4,15 @@ import { ref } from "vue";
 
 await initClient();
 
-export let serverInfo = ref<ApiMap["server-info"]["response"]>(await client.value.request("server-info"));
-export let account = ref<ApiMap["me"]["response"]>(await client.value.request("me"));
+let serverInfoDraft: ApiMap["server-info"]["response"] | null = null;
+let accountDraft: ApiMap["me"]["response"] | null = null;
+try {
+  serverInfoDraft = await client.value.request("server-info");
+  accountDraft = await client.value.request("me");
+} catch {}
+
+export let serverInfo = ref<ApiMap["server-info"]["response"] | null>(serverInfoDraft);
+export let account = ref<ApiMap["me"]["response"] | null>(accountDraft);
 export let presentCommunity = ref<Extract<ApiMap["community/list"]["response"], { communitys: any }>["communitys"][number]>();
 
 let communitys = ref<Extract<ApiMap["community/list"]["response"], { communitys: any }>["communitys"]>([]);
diff --git a/packages/frontend/src/lib/sw.ts b/packages/frontend/src/lib/sw.ts
index 8170517..bbb6c61 100644
--- a/packages/frontend/src/lib/sw.ts
+++ b/packages/frontend/src/lib/sw.ts
@@ -50,7 +50,13 @@ swSelf.addEventListener("fetch", (event) => {
     return;
 
   event.respondWith((async () => {
-    const cached = await caches.match(request);
+    let cached: Response | undefined;
+    if (request.destination === "document") {
+      cached = await caches.match("/index.html");
+    } else {
+      cached = await caches.match(request);
+    }
+
     if (cached)
       return cached;
 
diff --git a/packages/frontend/src/main.ts b/packages/frontend/src/main.ts
index 4268f17..3dc9aa9 100755
--- a/packages/frontend/src/main.ts
+++ b/packages/frontend/src/main.ts
@@ -90,7 +90,7 @@ router.afterEach((to, from) => {
 
   let serverName = "LynqChat";
 
-  if (serverInfo.value.success && serverInfo.value.name) {
+  if (serverInfo.value?.success && serverInfo.value.name) {
     serverName = serverInfo.value.name;
   }
 
diff --git a/packages/frontend/src/routes/community/channel.vue b/packages/frontend/src/routes/community/channel.vue
index 3efb379..1267fe2 100644
--- a/packages/frontend/src/routes/community/channel.vue
+++ b/packages/frontend/src/routes/community/channel.vue
@@ -137,7 +137,7 @@ import Message from "@/components/Message.vue";
 const route = useRoute();
 const router = useRouter();
 
-if (!serverInfo.value.success) {
+if (!serverInfo.value?.success) {
   throw new Error("サーバー情報の取得に失敗しました。");
 }
 
@@ -145,8 +145,8 @@ if (!serverInfo.value.isInitialized) {
   router.replace("/setup/initialization");
 }
 
-if (!account.value.success) {
-  switch (account.value.error.bad) {
+if (!account.value?.success) {
+  switch (account.value?.error.bad) {
     case "client":
       router.replace("/signin");
       break;
@@ -270,7 +270,7 @@ const send = async (e: Event) => {
     return;
   }
 
-  if (!account.value.success) {
+  if (!account.value?.success) {
     isSending.value = false;
     createModal({
       component: ErrorModal,
@@ -336,7 +336,7 @@ provide("now", now);
 (async () => {
   isProcessing.value = true;
 
-  if (!serverInfo.value.success) {
+  if (!serverInfo.value?.success) {
     throw new Error("サーバー情報の取得に失敗しました。");
   }
 
diff --git a/packages/frontend/src/routes/community/index.vue b/packages/frontend/src/routes/community/index.vue
index 553dda9..9fac8c9 100644
--- a/packages/frontend/src/routes/community/index.vue
+++ b/packages/frontend/src/routes/community/index.vue
@@ -137,7 +137,7 @@ const isProcessing = ref<boolean>(false);
 
 const channels = ref<Extract<ApiMap["channel/list"]["response"], { channels: any }>["channels"]>();
 
-if (!serverInfo.value.success) {
+if (!serverInfo.value?.success) {
   throw new Error("サーバー情報の取得に失敗しました。");
 }
 
@@ -145,8 +145,8 @@ if (!serverInfo.value.isInitialized) {
   router.replace("/setup/initialization");
 }
 
-if (!account.value.success) {
-  switch (account.value.error.bad) {
+if (!account.value?.success) {
+  switch (account.value?.error.bad) {
     case "client":
       router.replace("/signin");
       break;
@@ -158,7 +158,7 @@ if (!account.value.success) {
 (async () => {
   isProcessing.value = true;
 
-  if (!serverInfo.value.success) {
+  if (!serverInfo.value?.success) {
     throw new Error("サーバー情報の取得に失敗しました。");
   }
 
diff --git a/packages/frontend/src/routes/index.vue b/packages/frontend/src/routes/index.vue
index 23b580a..3f54d73 100755
--- a/packages/frontend/src/routes/index.vue
+++ b/packages/frontend/src/routes/index.vue
@@ -7,8 +7,8 @@ import { useRouter } from "vue-router";
 
 const router = useRouter();
 
-if (!account.value.success) {
-  switch (account.value.error.bad) {
+if (!account.value?.success) {
+  switch (account.value?.error.bad) {
     case "client":
       router.replace("/signin");
       break;
diff --git a/packages/frontend/src/routes/setup/create-admin.vue b/packages/frontend/src/routes/setup/create-admin.vue
index 8c76d87..36e3d6f 100644
--- a/packages/frontend/src/routes/setup/create-admin.vue
+++ b/packages/frontend/src/routes/setup/create-admin.vue
@@ -10,7 +10,7 @@
   <form novalidate @submit="submit">
     <Input
       label="ユーザーID"
-      autocomplete="userid"
+      autocomplete="username"
       v-model="userid"
     >
       <span
@@ -50,9 +50,10 @@
       </span>
 
       <span
-        class="password-strength"
+        class="input-issue password-strength"
         v-if="passwordStrength.message"
       >
+        <Icon :icon="passwordStrength.icon" />
         {{ passwordStrength.message }}
       </span>
     </InputPassword>
@@ -94,6 +95,10 @@ form {
   font-size: 1rem;
   margin: auto 0;
 }
+
+.password-strength {
+  color: v-bind(passwordStrengthColor);
+}
 </style>
 
 <script lang="ts" setup>
@@ -117,7 +122,7 @@ import { Icon } from "@iconify/vue";
 const router = useRouter();
 const isProcessing = ref<boolean>(false);
 
-if (!serverInfo.value.success) {
+if (!serverInfo.value?.success) {
   throw new Error("サーバー情報の取得に失敗しました。");
 }
 
@@ -137,19 +142,22 @@ const emailIssue = computed(() => getIssueFromPath("email", result.value));
 const passwordIssue = computed(() => getIssueFromPath("password", result.value));
 
 const passwordScores = [
-  "危険なパスワード",
-  "推測可能なパスワード",
-  "推測しやすいパスワード",
-  "安全なパスワード",
-  "強力なパスワード",
+  ["危険なパスワード", "error-outline-rounded", "var(--error-color)"],
+  ["推測可能なパスワード", "warning-rounded", "var(--warn-color)"],
+  ["推測しやすいパスワード", "warning-rounded", "var(--warn-color)"],
+  ["安全なパスワード", "check-circle", "var(--success-color)"],
+  ["強力なパスワード", "check-circle", "var(--success-color)"],
 ];
 const passwordStrength = computed(() => {
   const evaluation = zxcvbn(password.value);
   return {
-    message: passwordScores[evaluation.score],
+    message: passwordScores[evaluation.score]![0],
     score: evaluation.score,
+    icon: "material-symbols:" + passwordScores[evaluation.score]![1],
+    color: passwordScores[evaluation.score]![2],
   }
 });
+const passwordStrengthColor = computed(() => passwordStrength.value.color);
 
 const EmailRegex = /^(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:([0-9]{1,3}\.){3}[0-9]{1,3})\])$/i;
 const schema = z.object({
diff --git a/packages/frontend/src/routes/setup/initialization.vue b/packages/frontend/src/routes/setup/initialization.vue
index 37ef823..79f2e99 100644
--- a/packages/frontend/src/routes/setup/initialization.vue
+++ b/packages/frontend/src/routes/setup/initialization.vue
@@ -106,7 +106,7 @@ import Textarea from "@/components/Textarea.vue";
 const router = useRouter();
 const isProcessing = ref<boolean>(false);
 
-if (!serverInfo.value.success) {
+if (!serverInfo.value?.success) {
   throw new Error("サーバー情報の取得に失敗しました。");
 }
 
diff --git a/packages/frontend/src/routes/signin.vue b/packages/frontend/src/routes/signin.vue
index 39849b8..ea79059 100644
--- a/packages/frontend/src/routes/signin.vue
+++ b/packages/frontend/src/routes/signin.vue
@@ -2,7 +2,7 @@
   <form novalidate @submit="submit">
     <Input
       label="ユーザーID"
-      autocomplete="off"
+      autocomplete="username"
       v-model="userid"
     >
       <span
@@ -78,11 +78,11 @@ import z from "zod/v3";
 const router = useRouter();
 const isProcessing = ref<boolean>(false);
 
-if (account.value.success) {
+if (account.value?.success) {
   router.replace("/");
 }
 
-if (!serverInfo.value.success) {
+if (!serverInfo.value?.success) {
   throw new Error("サーバー情報の取得に失敗しました。");
 }
 
diff --git a/packages/frontend/vite.config.ts b/packages/frontend/vite.config.ts
index cc83772..928911e 100755
--- a/packages/frontend/vite.config.ts
+++ b/packages/frontend/vite.config.ts
@@ -14,7 +14,7 @@ export default defineConfig(({ mode }) => {
         strategies: "injectManifest",
         srcDir: "./src/lib",
         filename: "sw.ts",
-        injectRegister: "inline",
+        injectRegister: false,
         manifest: false,
         injectManifest: {
           globPatterns: ["**/*.{js,css,html,ico,png,svg}"],