diff --git a/src/components/AnnouncementBoard.css b/src/components/AnnouncementBoard.css
index 08c934c..77a56f8 100644
--- a/src/components/AnnouncementBoard.css
+++ b/src/components/AnnouncementBoard.css
@@ -58,6 +58,8 @@
   font-size: 0.9rem;
   color: rgba(255, 255, 255, 0.6);
   line-height: 1.6;
+  white-space: pre-wrap;
+  word-break: break-word;
 }
 
 .announcement-error {
diff --git a/src/components/DownloadSection.jsx b/src/components/DownloadSection.jsx
index 926dd70..5865e37 100644
--- a/src/components/DownloadSection.jsx
+++ b/src/components/DownloadSection.jsx
@@ -62,7 +62,16 @@ export default function DownloadSection() {
     }
   };
 
-  if (!ready) return null;
+  if (!ready) {
+    return (
+      <section className="download-section">
+        <div className="download-content">
+          <h2 className="download-title">One of the plans</h2>
+          <p className="download-meta">불러오는 중...</p>
+        </div>
+      </section>
+    );
+  }
 
   return (
     <section className="download-section">
diff --git a/src/components/admin/AnnouncementAdmin.jsx b/src/components/admin/AnnouncementAdmin.jsx
index f7c5acd..182c5f3 100644
--- a/src/components/admin/AnnouncementAdmin.jsx
+++ b/src/components/admin/AnnouncementAdmin.jsx
@@ -10,7 +10,9 @@ export default function AnnouncementAdmin() {
   const [error, setError] = useState('');
 
   const load = useCallback(() => {
-    getAnnouncements().then(setList).catch(() => {});
+    getAnnouncements().then(setList).catch((err) => {
+      console.error('공지사항 로드 실패:', err);
+    });
   }, []);
   useEffect(() => { load(); }, [load]);
 
diff --git a/src/components/admin/DownloadAdmin.jsx b/src/components/admin/DownloadAdmin.jsx
index 1a026e3..b4746fd 100644
--- a/src/components/admin/DownloadAdmin.jsx
+++ b/src/components/admin/DownloadAdmin.jsx
@@ -143,7 +143,9 @@ export default function DownloadAdmin() {
   const [info, setInfo] = useState(null);
 
   useEffect(() => {
-    getDownloadInfo().then(setInfo).catch(() => {});
+    getDownloadInfo().then(setInfo).catch((err) => {
+      console.error('다운로드 정보 로드 실패:', err);
+    });
   }, []);
 
   return (
diff --git a/src/components/admin/UserAdmin.jsx b/src/components/admin/UserAdmin.jsx
index 537e521..30a88cf 100644
--- a/src/components/admin/UserAdmin.jsx
+++ b/src/components/admin/UserAdmin.jsx
@@ -12,7 +12,7 @@ export default function UserAdmin() {
   const load = useCallback(() => {
     getUsers()
       .then(setUsers)
-      .catch(() => {})
+      .catch((err) => { console.error('유저 목록 로드 실패:', err); })
       .finally(() => setLoading(false));
   }, []);
   useEffect(() => { load(); }, [load]);
diff --git a/src/pages/LoginPage.jsx b/src/pages/LoginPage.jsx
index 8a7598a..e55ae65 100644
--- a/src/pages/LoginPage.jsx
+++ b/src/pages/LoginPage.jsx
@@ -63,7 +63,7 @@ export default function LoginPage() {
               onChange={(e) => setPassword(e.target.value)}
               placeholder="비밀번호를 입력하세요"
               autoComplete="current-password"
-              maxLength={100}
+              maxLength={72}
             />
           </div>
 
diff --git a/src/pages/RegisterPage.jsx b/src/pages/RegisterPage.jsx
index b9a320c..08fac2e 100644
--- a/src/pages/RegisterPage.jsx
+++ b/src/pages/RegisterPage.jsx
@@ -31,10 +31,19 @@ export default function RegisterPage() {
     e.preventDefault();
     setError('');
 
-    if (!username.trim()) {
+    const trimmed = username.trim().toLowerCase();
+    if (!trimmed) {
       setError('아이디를 입력해주세요.');
       return;
     }
+    if (trimmed.length < 3) {
+      setError('아이디는 3자 이상이어야 합니다.');
+      return;
+    }
+    if (!/^[a-z0-9_-]+$/.test(trimmed)) {
+      setError('아이디는 영문 소문자, 숫자, _, -만 사용 가능합니다.');
+      return;
+    }
     if (password !== confirm) {
       setError('비밀번호가 일치하지 않습니다.');
       return;
@@ -46,7 +55,7 @@ export default function RegisterPage() {
 
     setLoading(true);
     try {
-      await register(username, password);
+      await register(trimmed, password);
       navigate('/login', { state: { registered: true } });
     } catch (err) {
       setError(err.message || '회원가입에 실패했습니다.');
@@ -86,7 +95,7 @@ export default function RegisterPage() {
               onChange={(e) => setPassword(e.target.value)}
               placeholder="6자 이상 입력하세요"
               autoComplete="new-password"
-              maxLength={100}
+              maxLength={72}
             />
           </div>
 
@@ -105,7 +114,7 @@ export default function RegisterPage() {
               onChange={(e) => setConfirm(e.target.value)}
               placeholder="비밀번호를 다시 입력하세요"
               autoComplete="new-password"
-              maxLength={100}
+              maxLength={72}
             />
           </div>