fix: settings unsaved-changes guard, add Slate theme, improve Light theme

Unsaved-changes guard:
- _closeSettingsPanel() intercepts all three close paths (X button, overlay
  click, Escape key) and checks _settingsDirty before closing
- If dirty: shows inline 'Unsaved changes' bar with Save & Close / Discard
- Discard reverts the live theme preview to what it was when panel opened
- _markSettingsDirty() wired to all inputs via addEventListener in loadSettingsPanel()
- saveSettings() now resets dirty flag and hides the bar on successful save

Theme improvements:
- Add 'Slate' theme: warm charcoal (#2b2d30 bg), a softer/lighter dark option
  that sits between Dark and the full light themes
- Rework 'Light' theme: replace pure white (#f5f5f7) with warm off-white
  (#f0ede8) -- warmer, lower contrast, less harsh on most displays
- Update /theme command to include 'slate' in valid list
- Add test_settings_set_theme_slate() to test_sprint26.py

static/boot.js

@@ -226,7 +226,7 @@ document.addEventListener('keydown',async e=>{
   if(e.key==='Escape'){
     // Close settings overlay if open
     const settingsOverlay=$('settingsOverlay');
-    if(settingsOverlay&&settingsOverlay.style.display!=='none'){toggleSettings();return;}
+    if(settingsOverlay&&settingsOverlay.style.display!=='none'){_closeSettingsPanel();return;}
     // Close workspace dropdown
     closeWsDropdown();
     // Clear session search

static/commands.js

@@ -124,7 +124,7 @@ async function cmdUsage(){
 }
 
 async function cmdTheme(args){
-  const themes=['dark','light','solarized','monokai','nord'];
+  const themes=['dark','slate','light','solarized','monokai','nord'];
   if(!args||!themes.includes(args.toLowerCase())){
     showToast('Usage: /theme '+themes.join('|'));
     return;

static/index.html

@@ -312,7 +312,7 @@
   <div class="settings-panel">
     <div class="settings-header">
       <h3 style="margin:0;font-size:16px">Settings</h3>
-      <button class="panel-icon-btn" onclick="toggleSettings()" title="Close">&#10005;</button>
+      <button class="panel-icon-btn" onclick="_closeSettingsPanel()" title="Close">&#10005;</button>
     </div>
     <div class="settings-body">
       <div class="settings-field">
@@ -334,7 +334,8 @@
         <label for="settingsTheme">Theme</label>
         <select id="settingsTheme" style="width:100%;padding:8px;background:var(--code-bg);color:var(--text);border:1px solid var(--border2);border-radius:6px" onchange="document.documentElement.dataset.theme=this.value;localStorage.setItem('hermes-theme',this.value)">
           <option value="dark">Dark (default)</option>
-          <option value="light">Light</option>
+          <option value="slate">Slate (charcoal)</option>
+          <option value="light">Light (warm off-white)</option>
           <option value="solarized">Solarized Dark</option>
           <option value="monokai">Monokai</option>
           <option value="nord">Nord</option>

static/panels.js

@@ -908,17 +908,70 @@ document.addEventListener('drop',e=>{e.preventDefault();dragCounter=0;wrap.class
 
 // ── Settings panel ───────────────────────────────────────────────────────────
 
+let _settingsDirty = false;
+let _settingsThemeOnOpen = null; // track theme at open time for discard revert
+
 function toggleSettings(){
   const overlay=$('settingsOverlay');
   if(!overlay) return;
   if(overlay.style.display==='none'){
+    _settingsDirty = false;
+    _settingsThemeOnOpen = document.documentElement.dataset.theme || 'dark';
     overlay.style.display='';
     loadSettingsPanel();
   } else {
-    overlay.style.display='none';
+    _closeSettingsPanel();
   }
 }
 
+// Close with unsaved-changes check. If dirty, show a confirm dialog.
+function _closeSettingsPanel(){
+  if(!_settingsDirty){
+    // Nothing changed -- revert any live preview and close
+    _revertSettingsPreview();
+    $('settingsOverlay').style.display='none';
+    return;
+  }
+  // Dirty -- show inline confirm bar
+  _showSettingsUnsavedBar();
+}
+
+// Revert live DOM/localStorage to what they were when the panel opened
+function _revertSettingsPreview(){
+  if(_settingsThemeOnOpen){
+    document.documentElement.dataset.theme = _settingsThemeOnOpen;
+    localStorage.setItem('hermes-theme', _settingsThemeOnOpen);
+  }
+}
+
+// Show the "Unsaved changes" bar inside the settings panel
+function _showSettingsUnsavedBar(){
+  let bar = $('settingsUnsavedBar');
+  if(bar){ bar.style.display=''; return; }
+  // Create it
+  bar = document.createElement('div');
+  bar.id = 'settingsUnsavedBar';
+  bar.style.cssText = 'display:flex;align-items:center;justify-content:space-between;gap:8px;background:rgba(233,69,96,.12);border:1px solid rgba(233,69,96,.3);border-radius:8px;padding:10px 14px;margin:0 0 12px;font-size:13px;';
+  bar.innerHTML = '<span style="color:var(--text)">You have unsaved changes.</span>'
+    + '<span style="display:flex;gap:8px">'
+    + '<button onclick="_discardSettings()" style="padding:5px 12px;border-radius:6px;border:1px solid var(--border2);background:rgba(255,255,255,.06);color:var(--muted);cursor:pointer;font-size:12px;font-weight:600">Discard</button>'
+    + '<button onclick="saveSettings(true)" style="padding:5px 12px;border-radius:6px;border:none;background:var(--accent);color:#fff;cursor:pointer;font-size:12px;font-weight:600">Save & Close</button>'
+    + '</span>';
+  const body = document.querySelector('.settings-body') || document.querySelector('.settings-panel');
+  if(body) body.prepend(bar);
+}
+
+function _discardSettings(){
+  _revertSettingsPreview();
+  _settingsDirty = false;
+  $('settingsOverlay').style.display = 'none';
+}
+
+// Mark settings as dirty whenever anything changes
+function _markSettingsDirty(){
+  _settingsDirty = true;
+}
+
 async function loadSettingsPanel(){
   try{
     const settings=await api('/api/settings');
@@ -940,6 +993,7 @@ async function loadSettingsPanel(){
         }
       }catch(e){}
       modelSel.value=settings.default_model||'';
+      modelSel.addEventListener('change',_markSettingsDirty,{once:false});
     }
     // Populate workspace dropdown from /api/workspaces
     const wsSel=$('settingsWorkspace');
@@ -954,22 +1008,23 @@ async function loadSettingsPanel(){
         }
       }catch(e){}
       wsSel.value=settings.default_workspace||'';
+      wsSel.addEventListener('change',_markSettingsDirty,{once:false});
     }
     // Send key preference
     const sendKeySel=$('settingsSendKey');
-    if(sendKeySel) sendKeySel.value=settings.send_key||'enter';
+    if(sendKeySel){sendKeySel.value=settings.send_key||'enter';sendKeySel.addEventListener('change',_markSettingsDirty,{once:false});}
     // Theme preference
     const themeSel=$('settingsTheme');
-    if(themeSel) themeSel.value=settings.theme||'dark';
+    if(themeSel){themeSel.value=settings.theme||'dark';themeSel.addEventListener('change',_markSettingsDirty,{once:false});}
     const showUsageCb=$('settingsShowTokenUsage');
-    if(showUsageCb) showUsageCb.checked=!!settings.show_token_usage;
+    if(showUsageCb){showUsageCb.checked=!!settings.show_token_usage;showUsageCb.addEventListener('change',_markSettingsDirty,{once:false});}
     const showCliCb=$('settingsShowCliSessions');
-    if(showCliCb) showCliCb.checked=!!settings.show_cli_sessions;
+    if(showCliCb){showCliCb.checked=!!settings.show_cli_sessions;showCliCb.addEventListener('change',_markSettingsDirty,{once:false});}
     const syncCb=$('settingsSyncInsights');
-    if(syncCb) syncCb.checked=!!settings.sync_to_insights;
+    if(syncCb){syncCb.checked=!!settings.sync_to_insights;syncCb.addEventListener('change',_markSettingsDirty,{once:false});}
     // Password field: always blank (we don't send hash back)
     const pwField=$('settingsPassword');
-    if(pwField) pwField.value='';
+    if(pwField){pwField.value='';pwField.addEventListener('input',_markSettingsDirty,{once:false});}
     // Show auth buttons only when auth is active
     try{
       const authStatus=await api('/api/auth/status');
@@ -984,18 +1039,19 @@ async function loadSettingsPanel(){
   }
 }
 
-async function saveSettings(){
+async function saveSettings(andClose){
   const model=($('settingsModel')||{}).value;
   const workspace=($('settingsWorkspace')||{}).value;
   const sendKey=($('settingsSendKey')||{}).value;
   const showTokenUsage=!!($('settingsShowTokenUsage')||{}).checked;
   const showCliSessions=!!($('settingsShowCliSessions')||{}).checked;
   const pw=($('settingsPassword')||{}).value;
+  const theme=($('settingsTheme')||{}).value||'dark';
   const body={};
   if(model) body.default_model=model;
   if(workspace) body.default_workspace=workspace;
   if(sendKey) body.send_key=sendKey;
-  body.theme=($('settingsTheme')||{}).value||'dark';
+  body.theme=theme;
   body.show_token_usage=showTokenUsage;
   body.show_cli_sessions=showCliSessions;
   body.sync_to_insights=!!($('settingsSyncInsights')||{}).checked;
@@ -1006,7 +1062,9 @@ async function saveSettings(){
       window._sendKey=sendKey||'enter';
       window._showTokenUsage=showTokenUsage;
       showToast('Settings saved (password set — login now required)');
-      toggleSettings();
+      _settingsDirty=false; _settingsThemeOnOpen=theme;
+      const bar=$('settingsUnsavedBar'); if(bar) bar.style.display='none';
+      $('settingsOverlay').style.display='none';
       return;
     }catch(e){showToast('Save failed: '+e.message);return;}
   }
@@ -1015,10 +1073,12 @@ async function saveSettings(){
     window._sendKey=sendKey||'enter';
     window._showTokenUsage=showTokenUsage;
     window._showCliSessions=showCliSessions;
+    _settingsDirty=false; _settingsThemeOnOpen=theme;
+    const bar=$('settingsUnsavedBar'); if(bar) bar.style.display='none';
     renderMessages();
     if(typeof renderSessionList==='function') renderSessionList();
     showToast('Settings saved');
-    toggleSettings();
+    $('settingsOverlay').style.display='none';
   }catch(e){
     showToast('Save failed: '+e.message);
   }
@@ -1048,10 +1108,10 @@ async function disableAuth(){
   }
 }
 
-// Close settings on overlay click (not panel click)
+// Close settings on overlay click (not panel click) -- with unsaved-changes check
 document.addEventListener('click',e=>{
   const overlay=$('settingsOverlay');
-  if(overlay&&e.target===overlay) toggleSettings();
+  if(overlay&&e.target===overlay) _closeSettingsPanel();
 });
 
 // ── Cron completion alerts ────────────────────────────────────────────────────

static/style.css

@@ -4,14 +4,19 @@
     --text:#e8e8f0;--muted:#8888aa;--accent:#e94560;--blue:#7cb9ff;--gold:#c9a84c;--code-bg:#0d1117;
     font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",system-ui,sans-serif;font-size:14px;line-height:1.6;
   }
-  /* ── Light theme ── */
+  /* ── Slate theme (warm charcoal, lighter than dark, easier on the eyes) ── */
+  :root[data-theme="slate"]{
+    --bg:#2b2d30;--sidebar:#25272b;--border:rgba(255,255,255,0.09);--border2:rgba(255,255,255,0.16);
+    --text:#d4d4d8;--muted:#8a8a9a;--accent:#e06c75;--blue:#82aaff;--gold:#d4a85a;--code-bg:#1e2023;
+  }
+  /* ── Light theme (warm off-white, softer than pure white) ── */
   :root[data-theme="light"]{
-    --bg:#f5f5f7;--sidebar:#e8e8ed;--border:rgba(0,0,0,0.10);--border2:rgba(0,0,0,0.16);
+    --bg:#f0ede8;--sidebar:#e4e0d8;--border:rgba(0,0,0,0.09);--border2:rgba(0,0,0,0.15);
-    --text:#1c1c1e;--muted:#6e6e80;--accent:#c0392b;--blue:#0a6dc2;--gold:#a07a20;--code-bg:#f0f0f5;
+    --text:#2c2825;--muted:#7a746a;--accent:#b5451b;--blue:#2d6fa3;--gold:#8a6520;--code-bg:#e8e4de;
   }
   :root[data-theme="light"] ::-webkit-scrollbar-thumb{background:rgba(0,0,0,.15);}
   :root[data-theme="light"] ::-webkit-scrollbar-thumb:hover{background:rgba(0,0,0,.3);}
-  :root[data-theme="light"] ::selection{background:rgba(10,109,194,.2);}
+  :root[data-theme="light"] ::selection{background:rgba(45,111,163,.2);}
   /* ── Solarized Dark theme ── */
   :root[data-theme="solarized"]{
     --bg:#002b36;--sidebar:#073642;--border:rgba(255,255,255,0.08);--border2:rgba(255,255,255,0.13);

tests/test_sprint26.py

@@ -74,6 +74,16 @@ def test_settings_set_theme_nord():
         post("/api/settings", {"theme": "dark"})
 
 
+def test_settings_set_theme_slate():
+    """Setting theme to 'slate' should persist."""
+    try:
+        post("/api/settings", {"theme": "slate"})
+        d, _ = get("/api/settings")
+        assert d.get("theme") == "slate"
+    finally:
+        post("/api/settings", {"theme": "dark"})
+
+
 def test_settings_custom_theme_accepted():
     """Custom theme names should be accepted (no enum gate)."""
     try: