diff --git a/index.html b/index.html
index 74e8ab3..881db66 100644
--- a/index.html
+++ b/index.html
@@ -743,19 +743,22 @@ select.input {
   
   .mobile-nav {
     position: fixed;
-    left: 12px;
-    right: 12px;
-    bottom: max(12px, env(safe-area-inset-bottom));
+    left: 0;
+    right: 0;
+    bottom: 0;
     display: flex;
     justify-content: space-around;
     gap: 4px;
-    padding: 6px;
-    background: rgba(15, 22, 36, 0.88);
+    padding: 6px 8px calc(6px + env(safe-area-inset-bottom, 0px));
+    background: rgba(8, 12, 20, 0.95);
     backdrop-filter: blur(20px);
-    border: 1px solid var(--border-subtle);
-    border-radius: var(--radius-lg);
+    border-top: 1px solid var(--border-subtle);
+    border-left: 0;
+    border-right: 0;
+    border-bottom: 0;
+    border-radius: 0;
     z-index: 100;
-    box-shadow: var(--shadow-md);
+    box-shadow: 0 -4px 16px rgba(0, 0, 0, 0.3);
   }
   .mobile-nav button {
     flex: 1;
@@ -1301,7 +1304,42 @@ select.input {
 <script>
 
 const $=id=>document.getElementById(id);let searchPage=1,searchKeyword='',searchSource='kw',searchLoading=false,hasMore=false,taskFilter='all';
-async function api(u,o){const r=await fetch('/api'+u,o);if(r.status===401){showLogin();throw new Error('请先登录')}if(!r.ok)throw new Error(await r.text());return r.status===204?null:r.json()}
+function parseErrorMsg(msg) {
+  if (!msg) return '请求失败';
+  let str = String(msg).trim();
+  try {
+    const obj = JSON.parse(str);
+    if (obj && obj.error) str = String(obj.error);
+    else if (obj && obj.message) str = String(obj.message);
+  } catch(e) {}
+  const dict = {
+    'code already used or unavailable': '该兑换码已被使用或已失效',
+    'record not found': '兑换码不存在，请核对后重试',
+    'insufficient credits': '积分不足，请先兑换或充值积分',
+    'code expired': '该兑换码已过期',
+    'code required': '请输入兑换码',
+    'credits/count invalid': '积分或发行数量不合法',
+    'user not found': '用户不存在',
+    'user disabled': '账户已被禁用，无法执行此操作',
+    'amount must not be zero': '积分调整金额不能为 0',
+    'amount cannot be zero': '积分调整金额不能为 0',
+    'keyword required': '请输入搜索关键词',
+    'source/rid/title required': '歌曲信息不完整，无法加入下载队列',
+    'only failed tasks can be retried': '只有失败的任务才支持重试',
+    'invalid role': '无效的用户角色',
+    'invalid status': '无效的账户状态',
+    'invalid user id': '无效的用户 ID',
+    'invalid request body': '请求参数格式错误',
+    'username must be 4-10 English letters and password must be 8+ characters': '用户名必须为 4-10 位英文字母，密码至少 8 位',
+    'cannot remove the last active admin account': '系统必须保留至少一个激活的管理员账号',
+    'WebDAV URL、用户名或密码未配置': 'WebDAV URL、用户名或密码未配置'
+  };
+  for (const [k, v] of Object.entries(dict)) {
+    if (str.toLowerCase().includes(k.toLowerCase())) return v;
+  }
+  return str;
+}
+async function api(u,o){const r=await fetch('/api'+u,o);if(r.status===401){showLogin();throw new Error('请先登录')}if(!r.ok){const txt=await r.text();throw new Error(parseErrorMsg(txt))}return r.status===204?null:r.json()}
 function showLogin(){document.getElementById('loginOverlay').style.display='flex'}
 async function loadAccount(){try{const c=await api('/credits');$('creditPanel').textContent='余额 '+c.balance+' · 预留 '+c.reserved+' · 可用 '+c.available;const u=window.currentUser||{};$('userDavCard').style.display=(u.role==='admin'||u.role==='privileged')?'':'none';if(u.role==='admin'||u.role==='privileged'){const d=await api('/webdav/config');$('userDavUrl').value=d.url||'';$('userDavUser').value=d.username||'';$('userDavRoot').value=d.rootPath||''}}catch(e){$('creditPanel').textContent=e.message}}
 let adminUsersCache=[];let adminRoleFilter='all';