diff --git a/frontend/src/index.jsx b/frontend/src/index.jsx
index b2f5ed8..35f2880 100644
--- a/frontend/src/index.jsx
+++ b/frontend/src/index.jsx
@@ -461,6 +461,22 @@ const AppLayout = () => {
     const stored = window.localStorage.getItem('papercrate_view_mode');
     return stored === 'grid' ? 'grid' : 'list';
   });
+  const [neutralHue, setNeutralHue] = useState(() => {
+    if (typeof window === 'undefined') {
+      return 260;
+    }
+    const stored = window.localStorage.getItem('papercrate_neutral_hue');
+    if (stored) {
+      const parsedStored = Number.parseInt(stored, 10);
+      if (!Number.isNaN(parsedStored)) {
+        return parsedStored;
+      }
+    }
+    const root = document.documentElement;
+    const current = root.style.getPropertyValue('--neutral-hue');
+    const parsed = Number.parseInt(current, 10);
+    return Number.isNaN(parsed) ? 260 : parsed;
+  });
   const initialRowSelection = [];
   const [selectedRowKeys, setSelectedRowKeys] = useState(initialRowSelection);
   const [selectionOrder, setSelectionOrder] = useState(initialRowSelection);
@@ -558,6 +574,27 @@ const AppLayout = () => {
     }
   }, [token, appStatus, refreshAccessToken]);
 
+  useEffect(() => {
+    if (typeof document !== 'undefined') {
+      document.documentElement.style.setProperty('--neutral-hue', `${neutralHue}deg`);
+    }
+    if (typeof window !== 'undefined') {
+      window.localStorage.setItem('papercrate_neutral_hue', String(neutralHue));
+    }
+  }, [neutralHue]);
+
+  const handleNeutralHueChange = useCallback((value) => {
+    if (value === '') {
+      setNeutralHue(260);
+      return;
+    }
+    const parsed = Number(value);
+    if (Number.isNaN(parsed)) {
+      return;
+    }
+    setNeutralHue(parsed);
+  }, []);
+
   const clearFilters = useCallback(() => {
     setSearchQuery('');
     setActiveTagFilters([]);
@@ -5035,6 +5072,8 @@ const AppLayout = () => {
       draggedFolderId,
       onCreateFolder: handlePromptCreateFolder,
       creatingFolder,
+      onNeutralHueChange: handleNeutralHueChange,
+      neutralHue,
       tags,
       activeTagIds: activeTagFilters,
       onToggleTagFilter: toggleTagFilter,
@@ -5093,6 +5132,8 @@ const AppLayout = () => {
       handleCorrespondentCreate,
       handlePromptCreateFolder,
       creatingFolder,
+      handleNeutralHueChange,
+      neutralHue,
     ],
   );
 
diff --git a/frontend/src/sidebar/Sidebar.jsx b/frontend/src/sidebar/Sidebar.jsx
index be2e00d..92c01ff 100644
--- a/frontend/src/sidebar/Sidebar.jsx
+++ b/frontend/src/sidebar/Sidebar.jsx
@@ -11,6 +11,7 @@ import {
   CheckIcon,
   PlusIcon,
   FolderPlusIcon,
+  RestoreIcon,
 } from '../ui/icons';
 
 import { getTagColorStyle } from '../utils/colors';
@@ -142,6 +143,8 @@ const Sidebar = ({
   draggedFolderId,
   onCreateFolder,
   creatingFolder = false,
+  onNeutralHueChange,
+  neutralHue,
   tags = [],
   activeTagIds = [],
   onToggleTagFilter,
@@ -220,6 +223,10 @@ const Sidebar = ({
     onCreateFolder?.();
   }, [creatingFolder, onCreateFolder]);
 
+  const handleNeutralHueReset = useCallback(() => {
+    onNeutralHueChange?.('');
+  }, [onNeutralHueChange]);
+
   const handleSearchInputChange = useCallback(
     (event) => {
       onSearchChange?.(event.target.value);
@@ -587,6 +594,35 @@ const Sidebar = ({
             })}
           </ul>
         </div>
+        {typeof neutralHue === 'number' || typeof neutralHue === 'string' ? (
+          <div className="sidebar-section">
+            <div className="sidebar-section__header">
+              <h3>Theme</h3>
+              <div className="sidebar-section__actions">
+                <button
+                  type="button"
+                  className="icon-button"
+                  onClick={handleNeutralHueReset}
+                  aria-label="Reset neutral hue"
+                >
+                  <RestoreIcon size={16} />
+                </button>
+              </div>
+            </div>
+            <label className="sidebar-slider">
+              <span className="sidebar-slider__label">Neutral hue</span>
+              <input
+                type="range"
+                min="0"
+                max="360"
+                step="1"
+                value={neutralHue}
+                onChange={(event) => onNeutralHueChange?.(event.target.value)}
+              />
+              <span className="sidebar-slider__value">{neutralHue}°</span>
+            </label>
+          </div>
+        ) : null}
       </div>
     </aside>
   );
diff --git a/frontend/src/styles.css b/frontend/src/styles.css
index 3d6f8ff..941d0d1 100644
--- a/frontend/src/styles.css
+++ b/frontend/src/styles.css
@@ -1518,6 +1518,26 @@ button.danger:hover:not([disabled]) {
   color: var(--muted);
 }
 
+.sidebar-slider {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+  font-size: 0.8rem;
+  color: var(--muted);
+}
+
+.sidebar-slider input[type='range'] {
+  flex: 1;
+  accent-color: var(--accent);
+}
+
+.sidebar-slider__value {
+  min-width: 3rem;
+  text-align: right;
+  color: var(--fg);
+  font-variant-numeric: tabular-nums;
+}
+
 .sidebar-item {
   background: transparent;
   padding: 0.16rem 0.26rem;
diff --git a/frontend/src/ui/icons.js b/frontend/src/ui/icons.js
index f62f958..91af1e2 100644
--- a/frontend/src/ui/icons.js
+++ b/frontend/src/ui/icons.js
@@ -17,6 +17,7 @@ import {
   IconTextScan2,
   IconFolderPlus,
   IconRefresh,
+  IconRestore,
   IconMinusVertical,
   IconLogout,
   IconChevronDown,
@@ -171,6 +172,15 @@ export const RefreshIcon = ({ className, size = '1em', stroke = 1.6, ...rest })
   />
 );
 
+export const RestoreIcon = ({ className, size = '1em', stroke = 1.6, ...rest }) => (
+  <IconRestore
+    className={composeClassName('icon', className)}
+    size={size}
+    stroke={stroke}
+    {...rest}
+  />
+);
+
 export const ArrowUpIcon = ({ className, size = '1em', stroke = 1.6, ...rest }) => (
   <IconArrowUp
     className={composeClassName('icon', className)}