diff --git a/public/js/app.js b/public/js/app.js
index d1ed0b5..220520e 100644
--- a/public/js/app.js
+++ b/public/js/app.js
@@ -1813,22 +1813,17 @@
 
     const settings = {
       page_name: dom.pageNameInput.value.trim(),
-      title: dom.siteTitleInput.value.trim(),
-      logo_url: dom.logoUrlInput.value.trim(),
-      default_theme: dom.defaultThemeInput.value,
-      show_95_bandwidth: dom.show95BandwidthInput.value === "1" ? 1 : 0,
-      p95_type: dom.p95TypeSelect.value,
-      ps_filing: dom.psFilingInput ? dom.psFilingInput.value : '',
-      icp_filing: dom.icpFilingInput ? dom.icpFilingInput.value : '',
+      title: dom.siteTitleInput ? dom.siteTitleInput.value.trim() : dom.pageNameInput.value.trim(),
+      logo_url: dom.logoUrlInput ? dom.logoUrlInput.value.trim() : '',
       logo_url_dark: dom.logoUrlDarkInput ? dom.logoUrlDarkInput.value.trim() : '',
-      favicon_url: dom.faviconUrlInput ? dom.faviconUrlInput.value.trim() : ''
+      favicon_url: dom.faviconUrlInput ? dom.faviconUrlInput.value.trim() : '',
+      default_theme: dom.defaultThemeInput ? dom.defaultThemeInput.value : 'dark',
+      show_95_bandwidth: dom.show95BandwidthInput ? (dom.show95BandwidthInput.value === "1") : false,
+      p95_type: dom.p95TypeSelect ? dom.p95TypeSelect.value : 'tx',
+      ps_filing: dom.psFilingInput ? dom.psFilingInput.value.trim() : '',
+      icp_filing: dom.icpFilingInput ? dom.icpFilingInput.value.trim() : ''
     };
 
-    // If user sets default to auto, we should clear their manual override or set it to auto
-    if (settings.default_theme === 'auto') {
-      localStorage.setItem('theme', 'auto');
-    }
-
     dom.btnSaveSiteSettings.disabled = true;
     dom.btnSaveSiteSettings.textContent = '保存中...';
 
@@ -1841,17 +1836,20 @@
 
       if (response.ok) {
         showSiteMessage('设置保存成功', 'success');
-        applySiteSettings(settings);
+        // Update global object and UI immediately
+        window.SITE_SETTINGS = { ...window.SITE_SETTINGS, ...settings };
+        applySiteSettings(window.SITE_SETTINGS);
       } else {
         const err = await response.json();
-        showSiteMessage(`保存失败: ${err.error}`, 'error');
+        showSiteMessage(`保存失败: ${err.error || '未知错误'}`, 'error');
         if (response.status === 401) openLoginModal();
       }
     } catch (err) {
       showSiteMessage(`保存失败: ${err.message}`, 'error');
+      console.error('Save settings error:', err);
     } finally {
       dom.btnSaveSiteSettings.disabled = false;
-      dom.btnSaveSiteSettings.textContent = '保存基础设置';
+      dom.btnSaveSiteSettings.textContent = '保存设置';
     }
   }
 
diff --git a/server/db-integrity-check.js b/server/db-integrity-check.js
index f17e77d..08069b8 100644
--- a/server/db-integrity-check.js
+++ b/server/db-integrity-check.js
@@ -57,58 +57,41 @@ async function checkAndFixDatabase() {
     // Check for new columns in site_settings
     const [columns] = await db.query("SHOW COLUMNS FROM site_settings");
     const columnNames = columns.map(c => c.Field);
-    if (!columnNames.includes('show_95_bandwidth')) {
-      console.log(`[Database Integrity] ⚠️ Missing column 'show_95_bandwidth' in 'site_settings'. Adding it...`);
-      await db.query("ALTER TABLE site_settings ADD COLUMN show_95_bandwidth TINYINT(1) DEFAULT 0 AFTER default_theme");
-      console.log(`[Database Integrity] ✅ Column 'show_95_bandwidth' added.`);
-    }
-    if (!columnNames.includes('p95_type')) {
-      console.log(`[Database Integrity] ⚠️ Missing column 'p95_type' in 'site_settings'. Adding it...`);
-      await db.query("ALTER TABLE site_settings ADD COLUMN p95_type VARCHAR(20) DEFAULT 'tx' AFTER show_95_bandwidth");
-      console.log(`[Database Integrity] ✅ Column 'p95_type' added.`);
-    }
-    if (!columnNames.includes('blackbox_source_id')) {
-      console.log(`[Database Integrity] ⚠️ Missing column 'blackbox_source_id' in 'site_settings'. Adding it...`);
-      await db.query("ALTER TABLE site_settings ADD COLUMN blackbox_source_id INT AFTER p95_type");
-      console.log(`[Database Integrity] ✅ Column 'blackbox_source_id' added.`);
-    }
-    if (!columnNames.includes('latency_source')) {
-      console.log(`[Database Integrity] ⚠️ Missing column 'latency_source' in 'site_settings'. Adding it...`);
-      await db.query("ALTER TABLE site_settings ADD COLUMN latency_source VARCHAR(100) AFTER blackbox_source_id");
-      console.log(`[Database Integrity] ✅ Column 'latency_source' added.`);
-    }
-    if (!columnNames.includes('latency_dest')) {
-      console.log(`[Database Integrity] ⚠️ Missing column 'latency_dest' in 'site_settings'. Adding it...`);
-      await db.query("ALTER TABLE site_settings ADD COLUMN latency_dest VARCHAR(100) AFTER latency_source");
-      console.log(`[Database Integrity] ✅ Column 'latency_dest' added.`);
-    }
-    if (!columnNames.includes('latency_target')) {
-      console.log(`[Database Integrity] ⚠️ Missing column 'latency_target' in 'site_settings'. Adding it...`);
-      await db.query("ALTER TABLE site_settings ADD COLUMN latency_target VARCHAR(255) AFTER latency_dest");
-      console.log(`[Database Integrity] ✅ Column 'latency_target' added.`);
-    }
-    if (!columnNames.includes('icp_filing')) {
-      console.log(`[Database Integrity] ⚠️ Missing column 'icp_filing' in 'site_settings'. Adding it...`);
-      await db.query("ALTER TABLE site_settings ADD COLUMN icp_filing VARCHAR(255) AFTER latency_target");
-      console.log(`[Database Integrity] ✅ Column 'icp_filing' added.`);
-    }
-    if (!columnNames.includes('ps_filing')) {
-      console.log(`[Database Integrity] ⚠️ Missing column 'ps_filing' in 'site_settings'. Adding it...`);
-      await db.query("ALTER TABLE site_settings ADD COLUMN ps_filing VARCHAR(255) AFTER icp_filing");
-      console.log(`[Database Integrity] ✅ Column 'ps_filing' added.`);
-    }
-    if (!columnNames.includes('logo_url_dark')) {
-      console.log(`[Database Integrity] ⚠️ Missing column 'logo_url_dark' in 'site_settings'. Adding it...`);
-      await db.query("ALTER TABLE site_settings ADD COLUMN logo_url_dark TEXT AFTER logo_url");
-      console.log(`[Database Integrity] ✅ Column 'logo_url_dark' added.`);
-    }
-    if (!columnNames.includes('favicon_url')) {
-      console.log(`[Database Integrity] ⚠️ Missing column 'favicon_url' in 'site_settings'. Adding it...`);
-      await db.query("ALTER TABLE site_settings ADD COLUMN favicon_url TEXT AFTER logo_url_dark");
-      console.log(`[Database Integrity] ✅ Column 'favicon_url' added.`);
-    }
+    const addColumn = async (columnName, sql) => {
+      if (!columnNames.includes(columnName)) {
+        try {
+          console.log(`[Database Integrity] ⚠️ Missing column '${columnName}' in 'site_settings'. Adding it...`);
+          await db.query(sql);
+          console.log(`[Database Integrity] ✅ Column '${columnName}' added.`);
+        } catch (err) {
+          console.error(`[Database Integrity] ❌ Failed to add column '${columnName}':`, err.message);
+          // Try without AFTER if it exists
+          if (sql.includes('AFTER')) {
+            try {
+              const fallback = sql.split(' AFTER')[0];
+              console.log(`[Database Integrity] 🔄 Retrying column '${columnName}' WITHOUT 'AFTER'...`);
+              await db.query(fallback);
+              console.log(`[Database Integrity] ✅ Column '${columnName}' added via fallback.`);
+            } catch (err2) {
+              console.error(`[Database Integrity] ❌ Fallback also failed:`, err2.message);
+            }
+          }
+        }
+      }
+    };
+
+    await addColumn('show_95_bandwidth', "ALTER TABLE site_settings ADD COLUMN show_95_bandwidth TINYINT(1) DEFAULT 0 AFTER default_theme");
+    await addColumn('p95_type', "ALTER TABLE site_settings ADD COLUMN p95_type VARCHAR(20) DEFAULT 'tx' AFTER show_95_bandwidth");
+    await addColumn('blackbox_source_id', "ALTER TABLE site_settings ADD COLUMN blackbox_source_id INT AFTER p95_type");
+    await addColumn('latency_source', "ALTER TABLE site_settings ADD COLUMN latency_source VARCHAR(100) AFTER blackbox_source_id");
+    await addColumn('latency_dest', "ALTER TABLE site_settings ADD COLUMN latency_dest VARCHAR(100) AFTER latency_source");
+    await addColumn('latency_target', "ALTER TABLE site_settings ADD COLUMN latency_target VARCHAR(255) AFTER latency_dest");
+    await addColumn('icp_filing', "ALTER TABLE site_settings ADD COLUMN icp_filing VARCHAR(255) AFTER latency_target");
+    await addColumn('ps_filing', "ALTER TABLE site_settings ADD COLUMN ps_filing VARCHAR(255) AFTER icp_filing");
+    await addColumn('logo_url_dark', "ALTER TABLE site_settings ADD COLUMN logo_url_dark TEXT AFTER logo_url");
+    await addColumn('favicon_url', "ALTER TABLE site_settings ADD COLUMN favicon_url TEXT AFTER logo_url_dark");
   } catch (err) {
-    console.error('[Database Integrity] ❌ Error checking integrity:', err.message);
+    console.error('[Database Integrity] ❌ Overall site_settings check error:', err.message);
   }
 }
 
diff --git a/server/index.js b/server/index.js
index dff8037..a0eb227 100644
--- a/server/index.js
+++ b/server/index.js
@@ -588,34 +588,67 @@ app.get('/api/settings', async (req, res) => {
 
 // Update site settings
 app.post('/api/settings', requireAuth, async (req, res) => {
-    const { page_name, title, logo_url, logo_url_dark, favicon_url, default_theme, show_95_bandwidth, p95_type, blackbox_source_id, latency_source, latency_dest, latency_target, icp_filing, ps_filing } = req.body;
-    try {
-      await db.query(
-        `INSERT INTO site_settings (id, page_name, title, logo_url, logo_url_dark, favicon_url, default_theme, show_95_bandwidth, p95_type, blackbox_source_id, latency_source, latency_dest, latency_target, icp_filing, ps_filing) 
-         VALUES (1, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?) 
-         ON DUPLICATE KEY UPDATE 
-           page_name = VALUES(page_name), 
-           title = VALUES(title), 
-           logo_url = VALUES(logo_url),
-           logo_url_dark = VALUES(logo_url_dark),
-           favicon_url = VALUES(favicon_url),
-           default_theme = VALUES(default_theme),
-           show_95_bandwidth = VALUES(show_95_bandwidth),
-           p95_type = VALUES(p95_type),
-           blackbox_source_id = VALUES(blackbox_source_id),
-           latency_source = VALUES(latency_source),
-           latency_dest = VALUES(latency_dest),
-           latency_target = VALUES(latency_target),
-           icp_filing = VALUES(icp_filing),
-           ps_filing = VALUES(ps_filing)`,
-        [
-          page_name, title, logo_url, logo_url_dark, favicon_url, default_theme, 
-          show_95_bandwidth ? 1 : 0, p95_type || 'tx', 
-          blackbox_source_id || null, latency_source || null, 
-          latency_dest || null, latency_target || null,
-          icp_filing || null, ps_filing || null
-        ]
-      );
+  try {
+    // 1. Fetch current settings first to preserve fields not sent by the UI
+    const [rows] = await db.query('SELECT * FROM site_settings WHERE id = 1');
+    let current = rows.length > 0 ? rows[0] : {};
+
+    // 2. Destructure fields from body
+    const { 
+      page_name, title, logo_url, logo_url_dark, favicon_url, 
+      default_theme, show_95_bandwidth, p95_type, 
+      icp_filing, ps_filing 
+    } = req.body;
+
+    // 3. Prepare parameters, prioritizing body but falling back to current
+    const settings = {
+      page_name: page_name !== undefined ? page_name : (current.page_name || '数据可视化展示大屏'),
+      title: title !== undefined ? title : (current.title || '数据可视化展示大屏'),
+      logo_url: logo_url !== undefined ? logo_url : (current.logo_url || null),
+      logo_url_dark: logo_url_dark !== undefined ? logo_url_dark : (current.logo_url_dark || null),
+      favicon_url: favicon_url !== undefined ? favicon_url : (current.favicon_url || null),
+      default_theme: default_theme !== undefined ? default_theme : (current.default_theme || 'dark'),
+      show_95_bandwidth: show_95_bandwidth !== undefined ? (show_95_bandwidth ? 1 : 0) : (current.show_95_bandwidth || 0),
+      p95_type: p95_type !== undefined ? p95_type : (current.p95_type || 'tx'),
+      blackbox_source_id: current.blackbox_source_id || null, // UI doesn't send this
+      latency_source: current.latency_source || null,       // UI doesn't send this
+      latency_dest: current.latency_dest || null,           // UI doesn't send this
+      latency_target: current.latency_target || null,       // UI doesn't send this
+      icp_filing: icp_filing !== undefined ? icp_filing : (current.icp_filing || null),
+      ps_filing: ps_filing !== undefined ? ps_filing : (current.ps_filing || null)
+    };
+
+    // 4. Update database
+    await db.query(
+      `INSERT INTO site_settings (
+        id, page_name, title, logo_url, logo_url_dark, favicon_url, 
+        default_theme, show_95_bandwidth, p95_type, 
+        blackbox_source_id, latency_source, latency_dest, latency_target, 
+        icp_filing, ps_filing
+      ) VALUES (1, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?) 
+      ON DUPLICATE KEY UPDATE 
+        page_name = VALUES(page_name), 
+        title = VALUES(title), 
+        logo_url = VALUES(logo_url),
+        logo_url_dark = VALUES(logo_url_dark),
+        favicon_url = VALUES(favicon_url),
+        default_theme = VALUES(default_theme),
+        show_95_bandwidth = VALUES(show_95_bandwidth),
+        p95_type = VALUES(p95_type),
+        blackbox_source_id = VALUES(blackbox_source_id),
+        latency_source = VALUES(latency_source),
+        latency_dest = VALUES(latency_dest),
+        latency_target = VALUES(latency_target),
+        icp_filing = VALUES(icp_filing),
+        ps_filing = VALUES(ps_filing)`,
+      [
+        settings.page_name, settings.title, settings.logo_url, settings.logo_url_dark, settings.favicon_url,
+        settings.default_theme, settings.show_95_bandwidth, settings.p95_type,
+        settings.blackbox_source_id, settings.latency_source, settings.latency_dest, settings.latency_target,
+        settings.icp_filing, settings.ps_filing
+      ]
+    );
+
     res.json({ success: true });
   } catch (err) {
     console.error('Error updating settings:', err);