diff --git a/frontend/src/app/PanelManagerContext.tsx b/frontend/src/app/PanelManagerContext.tsx
index 714a640..feca22d 100644
--- a/frontend/src/app/PanelManagerContext.tsx
+++ b/frontend/src/app/PanelManagerContext.tsx
@@ -10,13 +10,16 @@ import React, {
 } from 'react';
 import type { CSSProperties, PointerEvent as ReactPointerEvent, RefObject } from 'react';
 import { useSidebarContext } from '../sidebar/SidebarContext';
-
-type PanelKey = 'sidebar' | 'detail';
-
-interface PanelLimits {
-  maxRatio: number;
-  minPx: number;
-}
+import {
+  DEFAULT_DETAIL_WIDTH,
+  DEFAULT_SIDEBAR_WIDTH,
+  MINIMAL_FREE_RATIO,
+  MINIMUM_MAIN_CONTENT_WIDTH,
+  PANEL_LIMITS,
+  PANEL_STORAGE_KEYS,
+  SIDEBAR_SOLO_THRESHOLD,
+  type PanelKey,
+} from '../constants/layout';
 
 interface SetPanelWidthOptions {
   commit?: boolean;
@@ -50,29 +53,6 @@ type PanelResizeBindings = {
 
 const PanelManagerContext = createContext<PanelManagerContextValue | null>(null);
 
-const PANEL_LIMITS: Record<PanelKey, PanelLimits> = {
-  sidebar: {
-    maxRatio: 1 / 3,
-    minPx: 280,
-  },
-  detail: {
-    maxRatio: 2 / 3,
-    minPx: 320,
-  },
-};
-
-const STORAGE_KEYS: Record<PanelKey, string> = {
-  sidebar: 'papercrate_sidebar_width',
-  detail: 'papercrate_detail_width',
-};
-
-const DEFAULT_SIDEBAR_WIDTH = 320;
-const DEFAULT_DETAIL_WIDTH = 420;
-
-const MINIMAL_FREE_RATIO = 1 / 3;
-const SIDEBAR_SOLO_THRESHOLD = 1 / 2;
-const MINIMUM_MAIN_CONTENT_WIDTH = 160;
-
 const clampPanelWidth = (panel: PanelKey, value: number): number => {
   const numeric = Number(value);
   const limits = PANEL_LIMITS[panel];
@@ -86,7 +66,7 @@ const clampPanelWidth = (panel: PanelKey, value: number): number => {
 };
 
 const readStoredWidth = (panel: PanelKey, fallback: number): number => {
-  const raw = window.localStorage.getItem(STORAGE_KEYS[panel]);
+  const raw = window.localStorage.getItem(PANEL_STORAGE_KEYS[panel]);
   if (!raw) {
     return fallback;
   }
@@ -95,7 +75,7 @@ const readStoredWidth = (panel: PanelKey, fallback: number): number => {
 };
 
 const persistWidth = (panel: PanelKey, value: number): void => {
-  window.localStorage.setItem(STORAGE_KEYS[panel], String(Math.round(value)));
+  window.localStorage.setItem(PANEL_STORAGE_KEYS[panel], String(Math.round(value)));
 };
 
 const applyPanelWidthToRoot = (panel: PanelKey, width: number, active: boolean): void => {
diff --git a/frontend/src/app/appState.tsx b/frontend/src/app/appState.tsx
index 0f3357d..2b2c485 100644
--- a/frontend/src/app/appState.tsx
+++ b/frontend/src/app/appState.tsx
@@ -2,6 +2,7 @@ import React, { useContext, useEffect, useMemo, useReducer } from 'react';
 import { clearAuthToken, setAuthToken, setAuthRefreshHandlers } from '../lib/apiClient';
 import { ApiProvider } from './ApiContext';
 import { listTenants } from '../lib/apiClient';
+import { STORED_TOKEN_KEY } from '../constants/app';
 
 type Tenant = Record<string, unknown> | null;
 
@@ -47,7 +48,7 @@ type AppAction =
 
 const storage = window.sessionStorage;
 
-const STORED_TOKEN = storage?.getItem('papercrate_token') ?? '';
+const storedToken = storage?.getItem(STORED_TOKEN_KEY) ?? '';
 let STORED_TENANT: Tenant = null;
 
 if (storage) {
@@ -61,13 +62,13 @@ if (storage) {
   }
 }
 
-if (STORED_TOKEN) {
-  setAuthToken(STORED_TOKEN);
+if (storedToken) {
+  setAuthToken(storedToken);
 }
 
 const initialAppState: AppState = {
-  status: STORED_TOKEN ? 'authenticated' : 'logged-out',
-  token: STORED_TOKEN,
+  status: storedToken ? 'authenticated' : 'logged-out',
+  token: storedToken,
   error: null,
   isRefreshing: false,
   tenantSelection: null,
diff --git a/frontend/src/app/entryKey.ts b/frontend/src/app/entryKey.ts
index a95d0ad..74e304b 100644
--- a/frontend/src/app/entryKey.ts
+++ b/frontend/src/app/entryKey.ts
@@ -1,10 +1,9 @@
 import type { DocumentId, FolderId } from '../types/identifiers';
+import { ENTRY_KEY_SEPARATOR } from '../constants/app';
 
 // Entry key utilities for workspace selection
 // Entry keys are strings in the format "document:id" or "folder:id"
 
-const ENTRY_KEY_SEPARATOR = ':';
-
 // Create entry key strings
 export const createDocumentEntryKey = (documentId: DocumentId): string =>
     `document${ENTRY_KEY_SEPARATOR}${documentId}`;
diff --git a/frontend/src/app/useDocumentsPreferences.ts b/frontend/src/app/useDocumentsPreferences.ts
index 8371916..91ed717 100644
--- a/frontend/src/app/useDocumentsPreferences.ts
+++ b/frontend/src/app/useDocumentsPreferences.ts
@@ -4,11 +4,12 @@ import {
   DEFAULT_SORT_FIELD,
   SORT_FIELD_VALUES,
 } from './workspaceUtils';
-
-const VIEW_MODE_STORAGE_KEY = 'papercrate_view_mode';
-const SORT_FIELD_STORAGE_KEY = 'papercrate_sort_field';
-const SORT_DIRECTION_STORAGE_KEY = 'papercrate_sort_direction';
-const INCLUDE_DESCENDANTS_STORAGE_KEY = 'papercrate_include_descendants';
+import {
+  INCLUDE_DESCENDANTS_STORAGE_KEY,
+  SORT_DIRECTION_STORAGE_KEY,
+  SORT_FIELD_STORAGE_KEY,
+  VIEW_MODE_STORAGE_KEY,
+} from '../constants/workspace';
 
 const readSessionStorage = (key: string): string | null => {
   try {
diff --git a/frontend/src/app/useManagementModals.tsx b/frontend/src/app/useManagementModals.tsx
index 8f44ca2..322763a 100644
--- a/frontend/src/app/useManagementModals.tsx
+++ b/frontend/src/app/useManagementModals.tsx
@@ -4,9 +4,7 @@ import TagsPanel from '../tags/TagsPanel';
 import CorrespondentsPanel, { CorrespondentsPanelProps } from '../correspondents/CorrespondentsPanel';
 import PanelHeader from '../ui/PanelHeader';
 import { CloseIcon } from '../ui/icons';
-
-const TAGS_MODAL = 'tags';
-const CORRESPONDENTS_MODAL = 'correspondents';
+import { CORRESPONDENTS_MODAL, TAGS_MODAL } from '../constants/app';
 
 interface TagRecord {
   id?: string;
diff --git a/frontend/src/app/workspaceUtils.ts b/frontend/src/app/workspaceUtils.ts
index b30fedb..55b1adb 100644
--- a/frontend/src/app/workspaceUtils.ts
+++ b/frontend/src/app/workspaceUtils.ts
@@ -1,8 +1,18 @@
-export const DEFAULT_FOLDER_NAME = 'Documents';
-export const DEFAULT_SORT_FIELD = 'title';
-export const DEFAULT_SORT_DIRECTION = 'asc';
-export const SORT_FIELD_VALUES = ['title', 'issued_at', 'created_at', 'updated_at'];
-export const TAG_FILTER_UNTAGGED = '__UNTAGGED__';
+import {
+  DEFAULT_FOLDER_NAME,
+  DEFAULT_SORT_DIRECTION,
+  DEFAULT_SORT_FIELD,
+  SORT_FIELD_VALUES,
+  TAG_FILTER_UNTAGGED,
+} from '../constants/workspace';
+
+export {
+  DEFAULT_FOLDER_NAME,
+  DEFAULT_SORT_DIRECTION,
+  DEFAULT_SORT_FIELD,
+  SORT_FIELD_VALUES,
+  TAG_FILTER_UNTAGGED,
+};
 
 export const hasFiles = (event) =>
   Array.from(event.dataTransfer?.types || []).includes('Files');
diff --git a/frontend/src/constants/app.ts b/frontend/src/constants/app.ts
new file mode 100644
index 0000000..0de6b27
--- /dev/null
+++ b/frontend/src/constants/app.ts
@@ -0,0 +1,4 @@
+export const ENTRY_KEY_SEPARATOR = ':';
+export const TAGS_MODAL = 'tags';
+export const CORRESPONDENTS_MODAL = 'correspondents';
+export const STORED_TOKEN_KEY = 'papercrate_token';
diff --git a/frontend/src/constants/colors.ts b/frontend/src/constants/colors.ts
new file mode 100644
index 0000000..b769eb1
--- /dev/null
+++ b/frontend/src/constants/colors.ts
@@ -0,0 +1 @@
+export const HEX_COLOR_PATTERN = /^#?([0-9a-fA-F]{6})$/;
diff --git a/frontend/src/constants/desktop.ts b/frontend/src/constants/desktop.ts
new file mode 100644
index 0000000..b24ec25
--- /dev/null
+++ b/frontend/src/constants/desktop.ts
@@ -0,0 +1,48 @@
+export const DB_NAME = 'papercrate_desk';
+export const DB_VERSION = 1;
+export const LAYOUT_STORE = 'layouts';
+
+export const CLICK_ACTIONS = {
+  selectSingle: 'selectSingle',
+  openDetail: 'openDetail',
+  addCard: 'addCard',
+  addStack: 'addStack',
+  none: 'none',
+} as const;
+
+export const DRAG_ACTIONS = {
+  dragSelectSingle: 'dragSelectSingle',
+  dragSelection: 'dragSelection',
+  dragSelectStack: 'dragSelectStack',
+  none: 'none',
+} as const;
+
+export const STACK_HIT_EPSILON = 4;
+export const POINTER_DRAG_THRESHOLD_SQUARED = 16;
+export const LONG_PRESS_DURATION_MS = 450;
+
+export const DRAG_HYSTERESIS_PX = 4;
+export const DRAG_HYSTERESIS_SQUARED = DRAG_HYSTERESIS_PX * DRAG_HYSTERESIS_PX;
+export const EDGE_COLLISION_THRESHOLD = 0.5;
+
+export const TAG_REMOVE_DISTANCE = 160;
+
+export const DEBUG_DRAG = false;
+export const DEBUG_FOCUS = false;
+
+export const DESK_CANVAS_PADDING = 24;
+export const DESK_ROTATION_RANGE = 7;
+export const DESK_DEFAULT_CANVAS_WIDTH = 1024;
+export const DESK_DEFAULT_CANVAS_HEIGHT = 680;
+export const DESK_CARD_MIN = 240;
+export const DESK_CARD_MAX = 340;
+export const CARD_PAGE_WEIGHT_GRAMS = 5;
+export const CARD_BASE_WEIGHT_GRAMS = 30;
+export const DEFAULT_Z_START = 10;
+export const MIN_TIMESTEP = 1 / 120;
+export const MAX_TIMESTEP = 1 / 20;
+export const MAX_DYNAMIC_ROTATION = 7;
+export const MAX_ANGULAR_VELOCITY = 210;
+export const ANGULAR_DAMPING = 10;
+export const TORQUE_TO_ACCELERATION = 0.007;
+export const SETTLE_ANGULAR_VELOCITY = 0.45;
diff --git a/frontend/src/constants/documents.ts b/frontend/src/constants/documents.ts
new file mode 100644
index 0000000..c1872a5
--- /dev/null
+++ b/frontend/src/constants/documents.ts
@@ -0,0 +1,18 @@
+export const DEFAULT_THUMBNAIL_SIZE = 48;
+
+export const TAG_MIME_TYPES = ['application/x-papercrate-tag', 'text/papercrate-tag'] as const;
+export const TAG_TEXT_MIME_TYPE = 'text/plain';
+
+export const DEFAULT_GRID_ICON_SIZE = 144;
+
+export const SORT_OPTIONS = [
+  { value: 'title', label: 'Title' },
+  { value: 'issued_at', label: 'Issued date' },
+  { value: 'created_at', label: 'Added' },
+  { value: 'updated_at', label: 'Updated date' },
+] as const;
+
+export const SORT_LABEL_LOOKUP = SORT_OPTIONS.reduce<Record<string, string>>((acc, option) => {
+  acc[option.value] = option.label;
+  return acc;
+}, {});
diff --git a/frontend/src/constants/layout.ts b/frontend/src/constants/layout.ts
new file mode 100644
index 0000000..74a6ace
--- /dev/null
+++ b/frontend/src/constants/layout.ts
@@ -0,0 +1,23 @@
+export const DEFAULT_SIDEBAR_WIDTH = 320;
+export const DEFAULT_DETAIL_WIDTH = 420;
+export const MINIMAL_FREE_RATIO = 1 / 3;
+export const SIDEBAR_SOLO_THRESHOLD = 1 / 2;
+export const MINIMUM_MAIN_CONTENT_WIDTH = 160;
+
+export type PanelKey = 'sidebar' | 'detail';
+
+export const PANEL_LIMITS: Record<PanelKey, { maxRatio: number; minPx: number }> = {
+  sidebar: {
+    maxRatio: 1 / 3,
+    minPx: 280,
+  },
+  detail: {
+    maxRatio: 2 / 3,
+    minPx: 320,
+  },
+};
+
+export const PANEL_STORAGE_KEYS: Record<PanelKey, string> = {
+  sidebar: 'papercrate_sidebar_width',
+  detail: 'papercrate_detail_width',
+};
diff --git a/frontend/src/constants/preview.ts b/frontend/src/constants/preview.ts
new file mode 100644
index 0000000..d568611
--- /dev/null
+++ b/frontend/src/constants/preview.ts
@@ -0,0 +1,32 @@
+export const RERENDER_DELTA = 48;
+export const MAX_PIXEL_RATIO = 2;
+export const FAST_SCROLL_VELOCITY_THRESHOLD = 0.8;
+export const FAST_SCROLL_DWELL_THRESHOLD_MS = 120;
+export const SCROLL_VELOCITY_MIN_DELTA = 0.05;
+
+export const AUDIO_EXTENSIONS = new Set([
+  'aac',
+  'aiff',
+  'flac',
+  'm4a',
+  'mp3',
+  'ogg',
+  'oga',
+  'opus',
+  'wav',
+  'weba',
+]);
+
+export const VIDEO_EXTENSIONS = new Set([
+  'avi',
+  'mkv',
+  'mov',
+  'mp4',
+  'm4v',
+  'webm',
+  'wmv',
+]);
+
+export const DOCUMENT_VIEWER_PORTRAIT_HEIGHT_RATIO = 0.4;
+export const PORTRAIT_RATIO_STYLE_ID = 'document-viewer-portrait-ratio-style';
+export const MIN_STACKED_BREAKPOINT = 480;
diff --git a/frontend/src/constants/settings.ts b/frontend/src/constants/settings.ts
new file mode 100644
index 0000000..c483948
--- /dev/null
+++ b/frontend/src/constants/settings.ts
@@ -0,0 +1,28 @@
+import type { SettingsSectionConfig } from '../settings/SettingsModal';
+import ApiTokensSection from '../settings/sections/ApiTokensSection';
+import CapabilitySetsSection from '../settings/sections/CapabilitySetsSection';
+import PasskeysSection from '../settings/sections/PasskeysSection';
+
+export const PASSKEYS_SECTION: SettingsSectionConfig = {
+  id: 'passkeys',
+  label: 'Passkeys',
+  component: PasskeysSection,
+};
+
+export const API_TOKENS_SECTION: SettingsSectionConfig = {
+  id: 'apiTokens',
+  label: 'API tokens',
+  component: ApiTokensSection,
+};
+
+export const CAPABILITY_SETS_SECTION: SettingsSectionConfig = {
+  id: 'capabilitySets',
+  label: 'Capability sets',
+  component: CapabilitySetsSection,
+};
+
+export const DEFAULT_SETTINGS_SECTIONS = [
+  PASSKEYS_SECTION,
+  API_TOKENS_SECTION,
+  CAPABILITY_SETS_SECTION,
+];
diff --git a/frontend/src/constants/sidebar.ts b/frontend/src/constants/sidebar.ts
new file mode 100644
index 0000000..ed24baf
--- /dev/null
+++ b/frontend/src/constants/sidebar.ts
@@ -0,0 +1,13 @@
+export const SIDEBAR_COLLAPSE_STORAGE_KEY = 'papercrate_sidebar_collapsed';
+export const THEME_STORAGE_KEY = 'papercrate_theme_settings';
+export const DEFAULT_NEUTRAL_HUE = 29;
+export const DEFAULT_NEUTRAL_CHROMA = 0.44;
+export const DEFAULT_NEUTRAL_CONTRAST = 0.56;
+export const DEFAULT_THEME_MODE = 'system';
+export const THEME_MODES = ['system', 'light', 'dark'];
+export const THEME_MODE_LABELS = {
+  system: 'System default',
+  light: 'Light',
+  dark: 'Dark',
+};
+export const DARK_MODE_MEDIA_QUERY = '(prefers-color-scheme: dark)';
diff --git a/frontend/src/constants/ui.ts b/frontend/src/constants/ui.ts
new file mode 100644
index 0000000..60c7d12
--- /dev/null
+++ b/frontend/src/constants/ui.ts
@@ -0,0 +1,7 @@
+export const NBSP = String.fromCharCode(160);
+export const DEFAULT_VIEWPORT_MARGIN = 8;
+
+export const ELLIPSIS = { id: '__breadcrumbs_ellipsis__', label: '…', onClick: null, raw: null } as const;
+export const WIDTH_TOLERANCE = 1;
+export const WIDTH_BUFFER_RATIO = 0.95;
+export const WIDTH_CHANGE_TOLERANCE = 0.25;
diff --git a/frontend/src/constants/workspace.ts b/frontend/src/constants/workspace.ts
new file mode 100644
index 0000000..33bec91
--- /dev/null
+++ b/frontend/src/constants/workspace.ts
@@ -0,0 +1,12 @@
+export const DEFAULT_FOLDER_NAME = 'Documents';
+export const DEFAULT_SORT_FIELD = 'title';
+export const DEFAULT_SORT_DIRECTION = 'asc';
+export const SORT_FIELD_VALUES = ['title', 'issued_at', 'created_at', 'updated_at'];
+export const TAG_FILTER_UNTAGGED = '__UNTAGGED__';
+
+export const VIEW_MODE_STORAGE_KEY = 'papercrate_view_mode';
+export const SORT_FIELD_STORAGE_KEY = 'papercrate_sort_field';
+export const SORT_DIRECTION_STORAGE_KEY = 'papercrate_sort_direction';
+export const INCLUDE_DESCENDANTS_STORAGE_KEY = 'papercrate_include_descendants';
+
+export const ROOT_FOLDER_LABEL = DEFAULT_FOLDER_NAME;
diff --git a/frontend/src/desktop/DesktopWorkspace.tsx b/frontend/src/desktop/DesktopWorkspace.tsx
index 7a95b93..9d9ad6f 100644
--- a/frontend/src/desktop/DesktopWorkspace.tsx
+++ b/frontend/src/desktop/DesktopWorkspace.tsx
@@ -25,6 +25,7 @@ import useDeskPointer from './pointer/useDeskPointer';
 import useDeskTagInteractions from './tags/useDeskTagInteractions';
 import DesktopDocumentCard from './DesktopDocumentCard';
 import usePreviewMetadata from './hooks/usePreviewMetadata';
+import { DEBUG_DRAG, DEBUG_FOCUS } from '../constants/desktop';
 import '../styles/workspace/workspace-layout.css';
 import '../styles/workspace/workspace-items.css';
 import '../styles/workspace/workspace-cards.css';
@@ -186,8 +187,6 @@ interface DesktopWorkspaceViewProps {
   markLayoutDirty: () => void;
 }
 
-const DEBUG_DRAG = false;
-const DEBUG_FOCUS = false;
 const defaultGetDocumentAsset: GetAsset = () => null;
 
 const DesktopWorkspace: React.FC<DesktopWorkspaceProps> = ({
diff --git a/frontend/src/desktop/db.ts b/frontend/src/desktop/db.ts
index d4c3116..2396025 100644
--- a/frontend/src/desktop/db.ts
+++ b/frontend/src/desktop/db.ts
@@ -1,10 +1,7 @@
 import type { DocumentId } from '../types/identifiers';
+import { DB_NAME, DB_VERSION, LAYOUT_STORE } from '../constants/desktop';
 type TenantId = import('../types/identifiers').TenantId;
 
-const DB_NAME = 'papercrate_desk';
-const DB_VERSION = 1;
-const LAYOUT_STORE = 'layouts';
-
 const currentDbPromise: { value: Promise<IDBDatabase | null> | null } = { value: null };
 
 const openDatabase = (): Promise<IDBDatabase> => {
diff --git a/frontend/src/desktop/pointer/pointerUtils.ts b/frontend/src/desktop/pointer/pointerUtils.ts
index 0d1e99f..31a7a2c 100644
--- a/frontend/src/desktop/pointer/pointerUtils.ts
+++ b/frontend/src/desktop/pointer/pointerUtils.ts
@@ -1,28 +1,18 @@
 import { safeInvoke } from '../events';
 import type { DocumentId } from '../../types/identifiers';
+import {
+  CLICK_ACTIONS,
+  DRAG_ACTIONS,
+  LONG_PRESS_DURATION_MS,
+  POINTER_DRAG_THRESHOLD_SQUARED,
+  STACK_HIT_EPSILON,
+} from '../../constants/desktop';
 
-export const CLICK_ACTIONS = {
-  selectSingle: 'selectSingle',
-  openDetail: 'openDetail',
-  addCard: 'addCard',
-  addStack: 'addStack',
-  none: 'none',
-} as const;
-
-export const DRAG_ACTIONS = {
-  dragSelectSingle: 'dragSelectSingle',
-  dragSelection: 'dragSelection',
-  dragSelectStack: 'dragSelectStack',
-  none: 'none',
-} as const;
+export { CLICK_ACTIONS, DRAG_ACTIONS, STACK_HIT_EPSILON, POINTER_DRAG_THRESHOLD_SQUARED, LONG_PRESS_DURATION_MS };
 
 export type ClickAction = (typeof CLICK_ACTIONS)[keyof typeof CLICK_ACTIONS];
 export type DragAction = (typeof DRAG_ACTIONS)[keyof typeof DRAG_ACTIONS];
 
-export const STACK_HIT_EPSILON = 4;
-export const POINTER_DRAG_THRESHOLD_SQUARED = 16;
-export const LONG_PRESS_DURATION_MS = 450;
-
 export const withinThreshold = (dx: number, dy: number, thresholdSquared: number): boolean => (dx * dx + dy * dy) <= thresholdSquared;
 
 interface PointerIntentArgs {
diff --git a/frontend/src/desktop/tags/useDeskTagInteractions.js b/frontend/src/desktop/tags/useDeskTagInteractions.js
index cc064b8..830e08d 100644
--- a/frontend/src/desktop/tags/useDeskTagInteractions.js
+++ b/frontend/src/desktop/tags/useDeskTagInteractions.js
@@ -9,8 +9,7 @@ import {
   parseTagTransferPayload,
   writeTagTransferData,
 } from '../../documents/tagTransfer';
-
-const TAG_REMOVE_DISTANCE = 160;
+import { TAG_REMOVE_DISTANCE } from '../../constants/desktop';
 
 const createDragPreview = (node, clientX, clientY) => {
   if (!(node instanceof HTMLElement)) {
diff --git a/frontend/src/desktop/useDocumentDrag.ts b/frontend/src/desktop/useDocumentDrag.ts
index cae7c07..1134741 100644
--- a/frontend/src/desktop/useDocumentDrag.ts
+++ b/frontend/src/desktop/useDocumentDrag.ts
@@ -19,6 +19,7 @@ import {
   applyDomTransform,
   type WorkspaceEngine,
 } from './workspaceEngine';
+import { DRAG_HYSTERESIS_SQUARED, EDGE_COLLISION_THRESHOLD } from '../constants/desktop';
 import type { DocumentId, Identifier } from '../types/identifiers';
 
 interface DocumentLike {
@@ -168,10 +169,6 @@ interface DragTapMetadata {
   docTitle: string;
 }
 
-const DRAG_HYSTERESIS_PX = 4;
-const DRAG_HYSTERESIS_SQUARED = DRAG_HYSTERESIS_PX * DRAG_HYSTERESIS_PX;
-const EDGE_COLLISION_THRESHOLD = 0.5;
-
 const getDocumentPageCount = (doc?: DocumentLike | null): number | null => {
   const raw = doc?.current_version?.metadata?.page_count ?? doc?.metadata?.page_count;
   if (raw == null) {
diff --git a/frontend/src/desktop/workspaceEngine.ts b/frontend/src/desktop/workspaceEngine.ts
index e3495d0..6341ea4 100644
--- a/frontend/src/desktop/workspaceEngine.ts
+++ b/frontend/src/desktop/workspaceEngine.ts
@@ -1,8 +1,44 @@
 import { clamp, formatTransform } from '../utils/math';
 import { fetchLayoutRecords, upsertLayoutRecords } from './db';
+import {
+  ANGULAR_DAMPING,
+  CARD_BASE_WEIGHT_GRAMS,
+  CARD_PAGE_WEIGHT_GRAMS,
+  DEFAULT_Z_START,
+  DESK_CANVAS_PADDING,
+  DESK_CARD_MAX,
+  DESK_CARD_MIN,
+  DESK_DEFAULT_CANVAS_HEIGHT,
+  DESK_DEFAULT_CANVAS_WIDTH,
+  DESK_ROTATION_RANGE,
+  MAX_ANGULAR_VELOCITY,
+  MAX_DYNAMIC_ROTATION,
+  MAX_TIMESTEP,
+  MIN_TIMESTEP,
+  SETTLE_ANGULAR_VELOCITY,
+  TORQUE_TO_ACCELERATION,
+} from '../constants/desktop';
 import type { DocumentId } from '../types/identifiers';
 type TenantId = import('../types/identifiers').TenantId;
 
+export {
+  ANGULAR_DAMPING,
+  CARD_BASE_WEIGHT_GRAMS,
+  CARD_PAGE_WEIGHT_GRAMS,
+  DESK_CANVAS_PADDING,
+  DESK_CARD_MAX,
+  DESK_CARD_MIN,
+  DESK_DEFAULT_CANVAS_HEIGHT,
+  DESK_DEFAULT_CANVAS_WIDTH,
+  DESK_ROTATION_RANGE,
+  MAX_ANGULAR_VELOCITY,
+  MAX_DYNAMIC_ROTATION,
+  MAX_TIMESTEP,
+  MIN_TIMESTEP,
+  SETTLE_ANGULAR_VELOCITY,
+  TORQUE_TO_ACCELERATION,
+};
+
 interface Point {
   x: number;
   y: number;
@@ -128,24 +164,6 @@ type UseSyncExternalStoreHook = <State>(
   getServerSnapshot: () => State,
 ) => State;
 
-export const DESK_CANVAS_PADDING = 24;
-export const DESK_ROTATION_RANGE = 7;
-export const DESK_DEFAULT_CANVAS_WIDTH = 1024;
-export const DESK_DEFAULT_CANVAS_HEIGHT = 680;
-export const DESK_CARD_MIN = 240;
-export const DESK_CARD_MAX = 340;
-export const CARD_PAGE_WEIGHT_GRAMS = 5;
-export const CARD_BASE_WEIGHT_GRAMS = 30;
-
-const DEFAULT_Z_START = 10;
-export const MIN_TIMESTEP = 1 / 120;
-export const MAX_TIMESTEP = 1 / 20;
-export const MAX_DYNAMIC_ROTATION = 7;
-export const MAX_ANGULAR_VELOCITY = 210;
-export const ANGULAR_DAMPING = 10;
-export const TORQUE_TO_ACCELERATION = 0.007;
-export const SETTLE_ANGULAR_VELOCITY = 0.45;
-
 const getMassScale = (massGrams?: number): number => {
   if (!Number.isFinite(massGrams) || Number(massGrams) <= 0) {
     return 1;
diff --git a/frontend/src/documents/CorrespondentLinks.tsx b/frontend/src/documents/CorrespondentLinks.tsx
index ff717de..e4612a1 100644
--- a/frontend/src/documents/CorrespondentLinks.tsx
+++ b/frontend/src/documents/CorrespondentLinks.tsx
@@ -1,6 +1,5 @@
 import React from 'react';
-
-const NBSP = String.fromCharCode(160);
+import { NBSP } from '../constants/ui';
 
 export interface CorrespondentLinkEntry {
   id?: string | null;
diff --git a/frontend/src/documents/DocumentThumbnailImage.tsx b/frontend/src/documents/DocumentThumbnailImage.tsx
index 8b9a1ae..2542505 100644
--- a/frontend/src/documents/DocumentThumbnailImage.tsx
+++ b/frontend/src/documents/DocumentThumbnailImage.tsx
@@ -5,6 +5,7 @@ import {
   resolveDocumentAssetUrl,
   resolveAssetUrl,
 } from '../asset_manager';
+import { DEFAULT_THUMBNAIL_SIZE } from '../constants/documents';
 import type {
   DocumentLike as AssetManagerDocumentLike,
   AssetLike as AssetManagerAssetLike,
@@ -12,8 +13,6 @@ import type {
   GetAsset as AssetManagerGetAsset,
 } from '../asset_manager';
 
-const DEFAULT_THUMBNAIL_SIZE = 48;
-
 // Detect when an element becomes visible within a scroll container so we can delay loading.
 const useLazyVisibility = (
   rootRef: MutableRefObject<Element | null> | null,
diff --git a/frontend/src/documents/SelectionFloatingActions.tsx b/frontend/src/documents/SelectionFloatingActions.tsx
index ded7c66..759cdc8 100644
--- a/frontend/src/documents/SelectionFloatingActions.tsx
+++ b/frontend/src/documents/SelectionFloatingActions.tsx
@@ -12,10 +12,9 @@ import SelectionAssignmentMenu, { SelectionAssignmentMenuItem } from './Selectio
 import SelectionSummary from './SelectionSummary';
 import { useAppState } from '../app/appState';
 import { useWorkspaceSelectionContext } from '../app/WorkspaceSelectionContext';
+import { DEFAULT_FOLDER_NAME } from '../constants/workspace';
 import type { DocumentId } from '../types/identifiers';
 
-const ROOT_FOLDER_LABEL = 'Documents';
-
 type NullableDocumentId = DocumentId | null;
 
 type SelectedIdList = NullableDocumentId[] | null;
@@ -128,11 +127,11 @@ const buildFolderTreeOptions = (tree?: FolderTreeNode[] | null): SelectionAssign
     });
   };
 
-  traverse(Array.isArray(tree) ? tree : [], [ROOT_FOLDER_LABEL]);
+  traverse(Array.isArray(tree) ? tree : [], [DEFAULT_FOLDER_NAME]);
 
   entries.sort((a, b) => (a.label || '').localeCompare(b.label || '', undefined, { sensitivity: 'base' }));
 
-  return [{ id: 'root', label: ROOT_FOLDER_LABEL, state: 'none', payload: { id: 'root' } }, ...entries];
+  return [{ id: 'root', label: DEFAULT_FOLDER_NAME, state: 'none', payload: { id: 'root' } }, ...entries];
 };
 
 const buildTagAssignments = (
diff --git a/frontend/src/documents/panel/DocumentsPanel.tsx b/frontend/src/documents/panel/DocumentsPanel.tsx
index 2079f7d..6ef3b24 100644
--- a/frontend/src/documents/panel/DocumentsPanel.tsx
+++ b/frontend/src/documents/panel/DocumentsPanel.tsx
@@ -18,10 +18,9 @@ import DocumentsPanelHeader, {
 import { SelectionFloatingPanel } from '../SelectionFloatingActions';
 import { createDocumentsTableHeaderActions } from './DocumentsToolbar';
 import { useDocumentsFilter } from '../context/DocumentsFilterContext';
+import { DEFAULT_GRID_ICON_SIZE } from '../../constants/documents';
 import type { Identifier } from '../../types/identifiers';
 
-const DEFAULT_GRID_ICON_SIZE = 144;
-
 const EntryType = {
   folder: 'folder',
   document: 'document',
diff --git a/frontend/src/documents/panel/SortFieldQuickMenu.tsx b/frontend/src/documents/panel/SortFieldQuickMenu.tsx
index f21db84..d603e78 100644
--- a/frontend/src/documents/panel/SortFieldQuickMenu.tsx
+++ b/frontend/src/documents/panel/SortFieldQuickMenu.tsx
@@ -1,19 +1,7 @@
 import React, { useCallback, useMemo } from 'react';
+import { SORT_LABEL_LOOKUP, SORT_OPTIONS } from '../../constants/documents';
 import QuickAddMenu from '../../ui/QuickAddMenu';
 
-const SORT_OPTIONS = [
-  { value: 'title', label: 'Title' },
-  { value: 'issued_at', label: 'Issued date' },
-  { value: 'created_at', label: 'Added' },
-  { value: 'updated_at', label: 'Updated date' },
-];
-
-const SORT_LABEL_LOOKUP = SORT_OPTIONS.reduce((acc, option) => {
-  const next = acc;
-  next[option.value] = option.label;
-  return next;
-}, {});
-
 interface SortFieldQuickMenuProps {
   sortField: string;
   onChange?: (value: string) => void;
diff --git a/frontend/src/documents/tagTransfer.ts b/frontend/src/documents/tagTransfer.ts
index 5c74201..b679466 100644
--- a/frontend/src/documents/tagTransfer.ts
+++ b/frontend/src/documents/tagTransfer.ts
@@ -1,7 +1,5 @@
 import type { DocumentId, TagId } from '../types/identifiers';
-
-const TAG_MIME_TYPES = ['application/x-papercrate-tag', 'text/papercrate-tag'];
-const TAG_TEXT_MIME_TYPE = 'text/plain';
+import { TAG_MIME_TYPES, TAG_TEXT_MIME_TYPE } from '../constants/documents';
 
 interface TagPayload {
   id: TagId;
diff --git a/frontend/src/preview/DocumentViewerLayout.tsx b/frontend/src/preview/DocumentViewerLayout.tsx
index 73760bd..efe8b41 100644
--- a/frontend/src/preview/DocumentViewerLayout.tsx
+++ b/frontend/src/preview/DocumentViewerLayout.tsx
@@ -3,6 +3,7 @@ import type { JSX } from 'react';
 import DocumentInfoPanel from '../documents/DocumentInfoPanel';
 import { DownloadIcon } from '../ui/icons';
 import PdfViewer from './PdfViewer';
+import { AUDIO_EXTENSIONS, VIDEO_EXTENSIONS } from '../constants/preview';
 
 interface DocumentLike {
   id?: string;
@@ -48,29 +49,6 @@ interface DocumentViewerLayoutProps {
   layoutMode?: LayoutMode;
 }
 
-const AUDIO_EXTENSIONS = new Set([
-  'aac',
-  'aiff',
-  'flac',
-  'm4a',
-  'mp3',
-  'ogg',
-  'oga',
-  'opus',
-  'wav',
-  'weba',
-]);
-
-const VIDEO_EXTENSIONS = new Set([
-  'avi',
-  'mkv',
-  'mov',
-  'mp4',
-  'm4v',
-  'webm',
-  'wmv',
-]);
-
 const getFileExtension = (filename?: string | null) => {
   if (!filename) {
     return '';
diff --git a/frontend/src/preview/PdfViewer.tsx b/frontend/src/preview/PdfViewer.tsx
index df39cc2..14ab38f 100644
--- a/frontend/src/preview/PdfViewer.tsx
+++ b/frontend/src/preview/PdfViewer.tsx
@@ -17,6 +17,13 @@ import type {
   PDFDocumentProxy,
   RenderTask,
 } from 'pdfjs-dist/types/src/display/api';
+import {
+  FAST_SCROLL_DWELL_THRESHOLD_MS,
+  FAST_SCROLL_VELOCITY_THRESHOLD,
+  MAX_PIXEL_RATIO,
+  RERENDER_DELTA,
+  SCROLL_VELOCITY_MIN_DELTA,
+} from '../constants/preview';
 GlobalWorkerOptions.workerSrc = new URL(
   'pdfjs-dist/build/pdf.worker.min.mjs',
   import.meta.url,
@@ -45,12 +52,6 @@ interface RenderQueueRequest {
   cancel: () => void;
 }
 
-const RERENDER_DELTA = 48;
-const MAX_PIXEL_RATIO = 2;
-const FAST_SCROLL_VELOCITY_THRESHOLD = 0.8; // px/ms ~ 800px/s
-const FAST_SCROLL_DWELL_THRESHOLD_MS = 120;
-const SCROLL_VELOCITY_MIN_DELTA = 0.05;
-
 const getAvailableViewportSize = (viewportNode: Element, stackNode: Element) => {
   const viewportStyle = window.getComputedStyle(viewportNode);
   const viewportPaddingX = parseFloat(viewportStyle.paddingLeft || '0')
diff --git a/frontend/src/preview/useViewerLayoutMode.ts b/frontend/src/preview/useViewerLayoutMode.ts
index 0d8dbf5..c16ee60 100644
--- a/frontend/src/preview/useViewerLayoutMode.ts
+++ b/frontend/src/preview/useViewerLayoutMode.ts
@@ -1,7 +1,11 @@
 import { MutableRefObject, useLayoutEffect, useState } from 'react';
+import {
+  DOCUMENT_VIEWER_PORTRAIT_HEIGHT_RATIO,
+  MIN_STACKED_BREAKPOINT,
+  PORTRAIT_RATIO_STYLE_ID,
+} from '../constants/preview';
 
-export const DOCUMENT_VIEWER_PORTRAIT_HEIGHT_RATIO = 0.4;
-const PORTRAIT_RATIO_STYLE_ID = 'document-viewer-portrait-ratio-style';
+export { DOCUMENT_VIEWER_PORTRAIT_HEIGHT_RATIO };
 
 const ensurePortraitRatioStyle = () => {
   const cssValue = String(DOCUMENT_VIEWER_PORTRAIT_HEIGHT_RATIO);
@@ -19,8 +23,6 @@ const ensurePortraitRatioStyle = () => {
   }
 };
 
-const MIN_STACKED_BREAKPOINT = 480;
-
 const computeStackedLayoutBreakpoint = () => Math.max(window.innerWidth / 2, MIN_STACKED_BREAKPOINT);
 
 export const useViewerLayoutMode = (
diff --git a/frontend/src/settings/sections/ApiTokensSection.tsx b/frontend/src/settings/sections/ApiTokensSection.tsx
index 0803b81..abb292c 100644
--- a/frontend/src/settings/sections/ApiTokensSection.tsx
+++ b/frontend/src/settings/sections/ApiTokensSection.tsx
@@ -489,10 +489,4 @@ const ApiTokensSection = ({
   );
 };
 
-export const API_TOKENS_SECTION = {
-  id: 'apiTokens',
-  label: 'API tokens',
-  component: ApiTokensSection,
-};
-
 export default ApiTokensSection;
diff --git a/frontend/src/settings/sections/CapabilitySetsSection.tsx b/frontend/src/settings/sections/CapabilitySetsSection.tsx
index 3806f14..f88174c 100644
--- a/frontend/src/settings/sections/CapabilitySetsSection.tsx
+++ b/frontend/src/settings/sections/CapabilitySetsSection.tsx
@@ -5,7 +5,6 @@ import React, {
   useMemo,
   useState,
 } from 'react';
-import type { SettingsSectionConfig } from '../SettingsModal';
 import { IconX } from '../../ui/icons';
 import CapabilityDropdown, { CapabilityDropdownOption } from '../components/CapabilityDropdown';
 import type { CapabilitySetId, CapabilityValue } from '../../types/identifiers';
@@ -641,10 +640,4 @@ const CapabilitySetsSection: React.FC<CapabilitySetsSectionProps> = ({
   );
 };
 
-export const CAPABILITY_SETS_SECTION: SettingsSectionConfig = {
-  id: 'capabilitySets',
-  label: 'Capability sets',
-  component: CapabilitySetsSection,
-};
-
 export default CapabilitySetsSection;
diff --git a/frontend/src/settings/sections/PasskeysSection.tsx b/frontend/src/settings/sections/PasskeysSection.tsx
index a3dee9f..ad1e4f4 100644
--- a/frontend/src/settings/sections/PasskeysSection.tsx
+++ b/frontend/src/settings/sections/PasskeysSection.tsx
@@ -172,10 +172,4 @@ const PasskeysSection = ({
   );
 };
 
-export const PASSKEYS_SECTION = {
-  id: 'passkeys',
-  label: 'Passkeys',
-  component: PasskeysSection,
-};
-
 export default PasskeysSection;
diff --git a/frontend/src/settings/sections/index.ts b/frontend/src/settings/sections/index.ts
index f0bad0d..6fe29ce 100644
--- a/frontend/src/settings/sections/index.ts
+++ b/frontend/src/settings/sections/index.ts
@@ -1,15 +1,12 @@
-import PasskeysSection, { PASSKEYS_SECTION } from './PasskeysSection';
-import ApiTokensSection, { API_TOKENS_SECTION } from './ApiTokensSection';
-import CapabilitySetsSection, { CAPABILITY_SETS_SECTION } from './CapabilitySetsSection';
-
-export const DEFAULT_SETTINGS_SECTIONS = [
-  PASSKEYS_SECTION,
+import PasskeysSection from './PasskeysSection';
+import ApiTokensSection from './ApiTokensSection';
+import CapabilitySetsSection from './CapabilitySetsSection';
+import {
   API_TOKENS_SECTION,
   CAPABILITY_SETS_SECTION,
-];
+  DEFAULT_SETTINGS_SECTIONS,
+  PASSKEYS_SECTION,
+} from '../../constants/settings';
 
-export {
-  PasskeysSection,
-  ApiTokensSection,
-  CapabilitySetsSection,
-};
+export { PasskeysSection, ApiTokensSection, CapabilitySetsSection };
+export { PASSKEYS_SECTION, API_TOKENS_SECTION, CAPABILITY_SETS_SECTION, DEFAULT_SETTINGS_SECTIONS };
diff --git a/frontend/src/sidebar/Sidebar.tsx b/frontend/src/sidebar/Sidebar.tsx
index 3cc0a91..4bacf50 100644
--- a/frontend/src/sidebar/Sidebar.tsx
+++ b/frontend/src/sidebar/Sidebar.tsx
@@ -32,6 +32,7 @@ import { useSidebarContext } from './SidebarContext';
 import { usePanelManager, usePanelResizeBindings } from '../app/PanelManagerContext';
 import type { StatusMessage } from '../hooks/documents/store/useDocumentsStore';
 import type { Identifier } from '../types/identifiers';
+import { THEME_MODE_LABELS, THEME_MODES } from '../constants/sidebar';
 
 interface CommunityLink {
   label: string;
@@ -260,13 +261,6 @@ const FolderNode: React.FC<FolderNodeProps> = ({
   );
 };
 
-const THEME_MODES = ['system', 'light', 'dark'];
-const THEME_MODE_LABELS = {
-  system: 'System',
-  light: 'Light',
-  dark: 'Dark',
-};
-
 interface FloatingMenuControls {
   isOpen: boolean;
   toggle: () => void;
diff --git a/frontend/src/sidebar/SidebarContext.tsx b/frontend/src/sidebar/SidebarContext.tsx
index 402ba68..ff6caa5 100644
--- a/frontend/src/sidebar/SidebarContext.tsx
+++ b/frontend/src/sidebar/SidebarContext.tsx
@@ -6,6 +6,16 @@ import React, {
   useCallback,
   useEffect,
 } from 'react';
+import {
+  DARK_MODE_MEDIA_QUERY,
+  DEFAULT_NEUTRAL_CHROMA,
+  DEFAULT_NEUTRAL_CONTRAST,
+  DEFAULT_NEUTRAL_HUE,
+  DEFAULT_THEME_MODE,
+  SIDEBAR_COLLAPSE_STORAGE_KEY,
+  THEME_MODES,
+  THEME_STORAGE_KEY,
+} from '../constants/sidebar';
 
 interface SidebarContextValue {
   collapsed: boolean;
@@ -25,20 +35,10 @@ interface SidebarContextValue {
   themeModes: ThemeMode[];
 }
 
-type ThemeMode = 'system' | 'light' | 'dark';
-
-const SIDEBAR_COLLAPSE_STORAGE_KEY = 'papercrate_sidebar_collapsed';
+type ThemeMode = (typeof THEME_MODES)[number];
 
 const SidebarContext = createContext<SidebarContextValue | null>(null);
 
-const THEME_STORAGE_KEY = 'papercrate_theme_settings';
-const DEFAULT_NEUTRAL_HUE = 29;
-const DEFAULT_NEUTRAL_CHROMA = 0.44;
-const DEFAULT_NEUTRAL_CONTRAST = 0.56;
-const DEFAULT_THEME_MODE = 'system';
-const THEME_MODES = ['system', 'light', 'dark'];
-const DARK_MODE_MEDIA_QUERY = '(prefers-color-scheme: dark)';
-
 const loadInitialThemeSettings = () => {
   const defaults = {
     neutralHue: DEFAULT_NEUTRAL_HUE,
diff --git a/frontend/src/ui/BreadcrumbTrail.tsx b/frontend/src/ui/BreadcrumbTrail.tsx
index 3c99321..0c83064 100644
--- a/frontend/src/ui/BreadcrumbTrail.tsx
+++ b/frontend/src/ui/BreadcrumbTrail.tsx
@@ -8,6 +8,12 @@ import React, {
 import { createPortal } from 'react-dom';
 import PropTypes from 'prop-types';
 import useFloatingMenu from './useFloatingMenu';
+import {
+  ELLIPSIS,
+  WIDTH_BUFFER_RATIO,
+  WIDTH_CHANGE_TOLERANCE,
+  WIDTH_TOLERANCE,
+} from '../constants/ui';
 
 const normalizeEntries = (entries) =>
   (Array.isArray(entries) ? entries : [])
@@ -22,11 +28,6 @@ const normalizeEntries = (entries) =>
     })
     .filter(Boolean);
 
-const ELLIPSIS = { id: '__breadcrumbs_ellipsis__', label: '…', onClick: null, raw: null };
-const WIDTH_TOLERANCE = 1;
-const WIDTH_BUFFER_RATIO = 0.95;
-const WIDTH_CHANGE_TOLERANCE = 0.25;
-
 const BreadcrumbTrail = ({
   entries = [],
   className = '',
diff --git a/frontend/src/ui/useFloatingMenu.ts b/frontend/src/ui/useFloatingMenu.ts
index 33e5af7..67c90ab 100644
--- a/frontend/src/ui/useFloatingMenu.ts
+++ b/frontend/src/ui/useFloatingMenu.ts
@@ -1,8 +1,7 @@
 import { useCallback, useEffect, useRef, useState } from 'react';
 import type { MutableRefObject, CSSProperties } from 'react';
 import { clamp } from '../utils/math';
-
-const DEFAULT_VIEWPORT_MARGIN = 8;
+import { DEFAULT_VIEWPORT_MARGIN } from '../constants/ui';
 
 type PositionStrategy = 'fixed' | 'absolute' | (string & {});
 
diff --git a/frontend/src/utils/colors.ts b/frontend/src/utils/colors.ts
index 15043af..de6eb18 100644
--- a/frontend/src/utils/colors.ts
+++ b/frontend/src/utils/colors.ts
@@ -1,4 +1,4 @@
-const HEX_COLOR_PATTERN = /^#?([0-9a-fA-F]{6})$/;
+import { HEX_COLOR_PATTERN } from '../constants/colors';
 
 const clamp01 = (value: number): number => Math.min(1, Math.max(0, value));