diff --git a/app/routers/web.py b/app/routers/web.py
index c11fd4b..bb5a5fc 100644
--- a/app/routers/web.py
+++ b/app/routers/web.py
@@ -47,6 +47,14 @@ def _to_local(dt: datetime) -> datetime:
     return dt.astimezone(_CST)
 
 
+def _to_utc(dt_str: str) -> datetime:
+    """Parse local datetime-local string and convert to UTC."""
+    dt = datetime.fromisoformat(dt_str)
+    if dt.tzinfo is None:
+        dt = dt.replace(tzinfo=_CST)
+    return dt.astimezone(timezone.utc).replace(tzinfo=None)
+
+
 templates.env.filters["to_local"] = _to_local
 
 
@@ -218,7 +226,7 @@ def admin_add_invite(
     if limit_type == "uses" and max_uses:
         m_uses = max_uses
     elif limit_type == "expires" and expires_at:
-        exp_at = datetime.fromisoformat(expires_at)
+        exp_at = _to_utc(expires_at)
     new_code = InviteCode(
         code=code, max_uses=m_uses, expires_at=exp_at,
         use_count=0, created_by=user.id,
@@ -251,7 +259,7 @@ def admin_edit_invite(
         code_obj.max_uses = max_uses
         code_obj.expires_at = None
     elif limit_type == "expires" and expires_at:
-        code_obj.expires_at = datetime.fromisoformat(expires_at)
+        code_obj.expires_at = _to_utc(expires_at)
         code_obj.max_uses = None
     else:
         code_obj.max_uses = None
diff --git a/app/templates/admin_invites.html b/app/templates/admin_invites.html
index 68bcc6c..0d6cd55 100644
--- a/app/templates/admin_invites.html
+++ b/app/templates/admin_invites.html
@@ -28,11 +28,11 @@
                 <option value="expires">有效期</option>
             </select>
         </div>
-        <div id="max_uses_field" style="display:none;align-items:center;gap:.3rem;align-self:flex-end">
+        <div id="max_uses_field" style="display:none;align-items:center;gap:.3rem">
             <label style="margin:0;font-size:.8rem;white-space:nowrap">次数</label>
             <input type="number" name="max_uses" min="1" value="1" class="aif-input aif-short">
         </div>
-        <div id="expires_field" style="display:none;align-items:center;gap:.3rem;align-self:flex-end">
+        <div id="expires_field" style="display:none;align-items:center;gap:.3rem">
             <label style="margin:0;font-size:.8rem;white-space:nowrap">有效期</label>
             <input type="datetime-local" name="expires_at" class="aif-input aif-date">
         </div>