diff --git a/packages/noodl-core-ui/src/components/inputs/TokenPicker/TokenPicker.module.scss b/packages/noodl-core-ui/src/components/inputs/TokenPicker/TokenPicker.module.scss
new file mode 100644
index 0000000..681a00d
--- /dev/null
+++ b/packages/noodl-core-ui/src/components/inputs/TokenPicker/TokenPicker.module.scss
@@ -0,0 +1,299 @@
+/**
+ * STYLE-001 Phase 3: TokenPicker styles
+ * All colours via design tokens — no hardcoded values.
+ */
+
+.TokenPicker {
+  position: relative;
+  display: flex;
+  flex-direction: column;
+  gap: var(--spacing-1, 4px);
+  width: 100%;
+}
+
+// ── Label ────────────────────────────────────────────────────────────────────
+
+.TokenPicker-label {
+  font-size: var(--font-size-xsmall, 11px);
+  font-weight: 500;
+  color: var(--theme-color-fg-default-shy);
+  text-transform: uppercase;
+  letter-spacing: 0.05em;
+  user-select: none;
+}
+
+// ── Trigger button ───────────────────────────────────────────────────────────
+
+.TokenPicker-trigger {
+  display: flex;
+  align-items: center;
+  gap: var(--spacing-1, 4px);
+  width: 100%;
+  padding: var(--spacing-1, 4px) var(--spacing-2, 8px);
+  background: var(--theme-color-bg-3);
+  color: var(--theme-color-fg-default);
+  border: 1px solid var(--theme-color-border-default);
+  border-radius: var(--border-radius-small, 4px);
+  font-size: var(--font-size-small, 12px);
+  cursor: pointer;
+  text-align: left;
+  transition: border-color 100ms ease, background 100ms ease;
+  min-height: 26px;
+
+  &:hover:not(:disabled) {
+    background: var(--theme-color-bg-2);
+    border-color: var(--theme-color-primary);
+  }
+
+  &:focus-visible {
+    outline: 2px solid var(--theme-color-primary);
+    outline-offset: 1px;
+  }
+
+  &:disabled {
+    opacity: 0.5;
+    cursor: not-allowed;
+  }
+
+  // When a token is selected — highlight border subtly
+  &--hasValue {
+    border-color: color-mix(in srgb, var(--theme-color-primary) 40%, var(--theme-color-border-default));
+  }
+}
+
+// Colour swatch in the trigger
+.TokenPicker-swatch {
+  display: inline-block;
+  width: 14px;
+  height: 14px;
+  border-radius: 2px;
+  border: 1px solid rgba(255, 255, 255, 0.15);
+  flex-shrink: 0;
+}
+
+.TokenPicker-triggerText {
+  flex: 1;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.TokenPicker-clearBtn {
+  flex-shrink: 0;
+  width: 16px;
+  height: 16px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  background: transparent;
+  border: none;
+  color: var(--theme-color-fg-default-shy);
+  font-size: 14px;
+  line-height: 1;
+  cursor: pointer;
+  border-radius: 2px;
+  padding: 0;
+
+  &:hover {
+    color: var(--theme-color-fg-default);
+    background: var(--theme-color-bg-2);
+  }
+}
+
+.TokenPicker-chevron {
+  flex-shrink: 0;
+  font-size: 10px;
+  color: var(--theme-color-fg-default-shy);
+  line-height: 1;
+  pointer-events: none;
+}
+
+// ── Dropdown panel ───────────────────────────────────────────────────────────
+
+.TokenPicker-dropdown {
+  position: absolute;
+  top: calc(100% + var(--spacing-1, 4px));
+  left: 0;
+  right: 0;
+  z-index: 300;
+  background: var(--theme-color-bg-2);
+  border: 1px solid var(--theme-color-border-default);
+  border-radius: var(--border-radius-small, 4px);
+  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.4);
+  display: flex;
+  flex-direction: column;
+  max-height: 320px;
+  overflow: hidden;
+  min-width: 200px;
+}
+
+// ── Search row ───────────────────────────────────────────────────────────────
+
+.TokenPicker-searchRow {
+  padding: var(--spacing-1, 4px) var(--spacing-2, 8px);
+  border-bottom: 1px solid var(--theme-color-border-default);
+  flex-shrink: 0;
+}
+
+.TokenPicker-search {
+  width: 100%;
+  padding: 3px var(--spacing-1, 4px);
+  background: var(--theme-color-bg-3);
+  color: var(--theme-color-fg-default);
+  border: 1px solid var(--theme-color-border-default);
+  border-radius: 3px;
+  font-size: var(--font-size-small, 12px);
+  outline: none;
+
+  &::placeholder {
+    color: var(--theme-color-fg-default-shy);
+  }
+
+  &:focus {
+    border-color: var(--theme-color-primary);
+  }
+}
+
+// ── Token list ───────────────────────────────────────────────────────────────
+
+.TokenPicker-list {
+  overflow-y: auto;
+  flex: 1;
+}
+
+.TokenPicker-empty {
+  padding: var(--spacing-2, 8px) var(--spacing-3, 12px);
+  font-size: var(--font-size-small, 12px);
+  color: var(--theme-color-fg-default-shy);
+  text-align: center;
+}
+
+// ── Token group ───────────────────────────────────────────────────────────────
+
+.TokenPicker-group {
+  & + & {
+    border-top: 1px solid var(--theme-color-border-default);
+  }
+}
+
+.TokenPicker-groupLabel {
+  display: block;
+  padding: var(--spacing-1, 4px) var(--spacing-2, 8px);
+  font-size: 10px;
+  font-weight: 600;
+  text-transform: uppercase;
+  letter-spacing: 0.06em;
+  color: var(--theme-color-fg-default-shy);
+  user-select: none;
+  position: sticky;
+  top: 0;
+  background: var(--theme-color-bg-2);
+  z-index: 1;
+}
+
+// ── Token option ─────────────────────────────────────────────────────────────
+
+.TokenPicker-option {
+  display: flex;
+  align-items: center;
+  gap: var(--spacing-1, 4px);
+  padding: 3px var(--spacing-2, 8px);
+  background: transparent;
+  color: var(--theme-color-fg-default);
+  border: none;
+  font-size: var(--font-size-small, 12px);
+  cursor: pointer;
+  text-align: left;
+  width: 100%;
+  transition: background 60ms ease;
+
+  &:hover {
+    background: var(--theme-color-bg-3);
+  }
+
+  &--active {
+    color: var(--theme-color-primary);
+    background: color-mix(in srgb, var(--theme-color-primary) 10%, transparent);
+
+    &:hover {
+      background: color-mix(in srgb, var(--theme-color-primary) 15%, transparent);
+    }
+  }
+
+  // Custom tokens get a subtle tint
+  &--custom {
+    .TokenPicker-optionName {
+      font-style: italic;
+    }
+  }
+}
+
+.TokenPicker-optionPreview {
+  flex-shrink: 0;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  width: 20px;
+  height: 20px;
+}
+
+.TokenPicker-optionSwatch {
+  display: block;
+  width: 14px;
+  height: 14px;
+  border-radius: 3px;
+  border: 1px solid rgba(255, 255, 255, 0.12);
+  flex-shrink: 0;
+}
+
+.TokenPicker-optionValueBadge {
+  display: block;
+  font-size: 9px;
+  font-weight: 600;
+  color: var(--theme-color-fg-default-shy);
+  text-transform: uppercase;
+  letter-spacing: 0;
+  max-width: 20px;
+  overflow: hidden;
+  text-overflow: clip;
+  white-space: nowrap;
+}
+
+.TokenPicker-optionBody {
+  flex: 1;
+  overflow: hidden;
+  display: flex;
+  flex-direction: column;
+  gap: 1px;
+}
+
+.TokenPicker-optionName {
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  font-size: var(--font-size-small, 12px);
+  line-height: 1.3;
+}
+
+.TokenPicker-optionValue {
+  font-size: 10px;
+  color: var(--theme-color-fg-default-shy);
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  line-height: 1.2;
+}
+
+.TokenPicker-customBadge {
+  flex-shrink: 0;
+  font-size: 9px;
+  color: var(--theme-color-primary);
+  opacity: 0.7;
+}
+
+.TokenPicker-checkmark {
+  flex-shrink: 0;
+  font-size: 10px;
+  color: var(--theme-color-primary);
+  line-height: 1;
+}
diff --git a/packages/noodl-core-ui/src/components/inputs/TokenPicker/TokenPicker.tsx b/packages/noodl-core-ui/src/components/inputs/TokenPicker/TokenPicker.tsx
new file mode 100644
index 0000000..c48ef2c
--- /dev/null
+++ b/packages/noodl-core-ui/src/components/inputs/TokenPicker/TokenPicker.tsx
@@ -0,0 +1,397 @@
+/**
+ * STYLE-001 Phase 3: TokenPicker
+ *
+ * Reusable dropdown component for selecting a design token to bind to a CSS property.
+ * Displays the current token (with colour swatch preview for colour tokens) and opens
+ * a searchable, grouped list of all available tokens.
+ *
+ * This component is fully dumb — it receives tokens as plain data and fires callbacks.
+ * Token resolution (var() → actual CSS value) must be done by the caller before passing
+ * items in. This keeps noodl-core-ui free of editor-specific model dependencies.
+ *
+ * Usage:
+ *   <TokenPicker
+ *     tokens={allTokens.map(t => ({ ...t, resolvedValue: model.resolveToken(t.name) }))}
+ *     selectedToken="--primary"
+ *     onTokenSelect={(cssVar) => applyValue(cssVar)}
+ *     onClear={() => applyValue('')}
+ *     filterCategories={['color-semantic', 'color-palette']}
+ *     label="Background Color"
+ *   />
+ */
+
+import React, { useCallback, useEffect, useMemo, useRef, useState } from 'react';
+
+import css from './TokenPicker.module.scss';
+
+// ─── Public types (no editor dependencies) ───────────────────────────────────
+
+export interface TokenPickerItem {
+  /** CSS custom property name, e.g. '--primary' */
+  name: string;
+  /** Raw token value — may be a var() reference */
+  value: string;
+  /** Resolved CSS value for preview rendering, e.g. '#3b82f6'. Pre-resolved by caller. */
+  resolvedValue?: string;
+  /** Category string matching TokenCategory in the editor, e.g. 'color-semantic' */
+  category: string;
+  /** Whether this token has been customised from the project defaults */
+  isCustom?: boolean;
+  /** Optional description shown in the dropdown */
+  description?: string;
+}
+
+export interface TokenPickerGroup {
+  /** Display label for the group header */
+  label: string;
+  /** Tokens belonging to this group */
+  tokens: TokenPickerItem[];
+}
+
+export interface TokenPickerProps {
+  /** All available tokens to show in the dropdown. */
+  tokens: TokenPickerItem[];
+
+  /**
+   * Groups to use for displaying tokens in the dropdown.
+   * If provided, overrides the auto-grouping from `groupBy`.
+   */
+  groups?: TokenPickerGroup[];
+
+  /**
+   * Derive the display group label from a category string.
+   * Defaults to capitalising the category's prefix (e.g. 'color-semantic' → 'Colors').
+   */
+  groupBy?: (category: string) => string;
+
+  /**
+   * Currently selected token name (CSS custom property name, without var() wrapper).
+   * Pass null or undefined if no token is currently selected.
+   */
+  selectedToken: string | null | undefined;
+
+  /**
+   * Called when the user picks a token.
+   * The argument is the full CSS `var(--token-name)` string, ready to use as a style value.
+   */
+  onTokenSelect: (cssVar: string) => void;
+
+  /**
+   * Called when the user clears the token selection.
+   * If not provided, the clear button is hidden.
+   */
+  onClear?: () => void;
+
+  /** Filter to specific category strings. When empty/undefined, all tokens are shown. */
+  filterCategories?: string[];
+
+  /** Label shown above the trigger button. */
+  label?: string;
+
+  /** Placeholder text when no token is selected. Defaults to 'Choose token'. */
+  placeholder?: string;
+
+  /** Disable the picker. */
+  disabled?: boolean;
+}
+
+// ─── Helpers ─────────────────────────────────────────────────────────────────
+
+/** Detect whether a value (or category) represents a colour. */
+function isColorCategory(category: string): boolean {
+  return category.startsWith('color');
+}
+
+/** Check whether a resolved CSS value looks like a colour (hex, rgb, hsl, named). */
+function looksLikeColor(value: string): boolean {
+  const v = value.trim();
+  return (
+    v.startsWith('#') || v.startsWith('rgb') || v.startsWith('hsl') || /^[a-z]+$/.test(v) // css named colours
+  );
+}
+
+/**
+ * Format a token name for display.
+ * '--color-primary' → 'color-primary'
+ * '--space-4' → 'space-4'
+ */
+function formatTokenLabel(name: string): string {
+  return name.replace(/^--/, '');
+}
+
+/**
+ * Derive a group label from a category string.
+ * 'color-semantic' → 'Colors'
+ * 'typography-size' → 'Typography'
+ * 'border-radius' → 'Borders'
+ */
+function defaultGroupBy(category: string): string {
+  const prefix = category.split('-')[0];
+  const map: Record<string, string> = {
+    color: 'Colors',
+    spacing: 'Spacing',
+    typography: 'Typography',
+    border: 'Borders',
+    shadow: 'Effects',
+    animation: 'Animation'
+  };
+  return map[prefix] ?? prefix.charAt(0).toUpperCase() + prefix.slice(1);
+}
+
+/** Group a flat token list into labelled groups, preserving insertion order. */
+function buildGroups(tokens: TokenPickerItem[], groupBy: (cat: string) => string): TokenPickerGroup[] {
+  const map = new Map<string, TokenPickerItem[]>();
+  for (const token of tokens) {
+    const label = groupBy(token.category);
+    if (!map.has(label)) map.set(label, []);
+    map.get(label)!.push(token);
+  }
+  return Array.from(map.entries()).map(([label, items]) => ({ label, tokens: items }));
+}
+
+// ─── Component ───────────────────────────────────────────────────────────────
+
+export function TokenPicker({
+  tokens,
+  groups: groupsProp,
+  groupBy = defaultGroupBy,
+  selectedToken,
+  onTokenSelect,
+  onClear,
+  filterCategories,
+  label,
+  placeholder = 'Choose token',
+  disabled = false
+}: TokenPickerProps) {
+  const [isOpen, setIsOpen] = useState(false);
+  const [search, setSearch] = useState('');
+  const containerRef = useRef<HTMLDivElement>(null);
+  const searchRef = useRef<HTMLInputElement>(null);
+
+  // Resolve the currently selected token item
+  const selectedItem = useMemo(
+    () => (selectedToken ? tokens.find((t) => t.name === selectedToken) ?? null : null),
+    [tokens, selectedToken]
+  );
+
+  // Filter & group tokens for the dropdown
+  const visibleGroups = useMemo<TokenPickerGroup[]>(() => {
+    // Start from explicit groups or auto-build them
+    const source = groupsProp ?? buildGroups(tokens, groupBy);
+
+    // Apply category filter
+    const categorized =
+      filterCategories && filterCategories.length > 0
+        ? source.map((g) => ({ ...g, tokens: g.tokens.filter((t) => filterCategories.includes(t.category)) }))
+        : source;
+
+    // Apply search filter
+    const q = search.trim().toLowerCase();
+    if (!q) return categorized.filter((g) => g.tokens.length > 0);
+
+    return categorized
+      .map((g) => ({
+        ...g,
+        tokens: g.tokens.filter(
+          (t) =>
+            t.name.toLowerCase().includes(q) ||
+            (t.description ?? '').toLowerCase().includes(q) ||
+            (t.resolvedValue ?? t.value).toLowerCase().includes(q)
+        )
+      }))
+      .filter((g) => g.tokens.length > 0);
+  }, [tokens, groupsProp, groupBy, filterCategories, search]);
+
+  // ── Event handlers ──────────────────────────────────────────────────────
+
+  const open = useCallback(() => {
+    if (!disabled) {
+      setIsOpen(true);
+      setSearch('');
+    }
+  }, [disabled]);
+
+  const close = useCallback(() => {
+    setIsOpen(false);
+    setSearch('');
+  }, []);
+
+  const handleSelect = useCallback(
+    (item: TokenPickerItem) => {
+      close();
+      onTokenSelect(`var(${item.name})`);
+    },
+    [close, onTokenSelect]
+  );
+
+  const handleClear = useCallback(
+    (e: React.MouseEvent) => {
+      e.stopPropagation();
+      close();
+      onClear?.();
+    },
+    [close, onClear]
+  );
+
+  // Focus search on open
+  useEffect(() => {
+    if (isOpen) {
+      requestAnimationFrame(() => searchRef.current?.focus());
+    }
+  }, [isOpen]);
+
+  // Close on outside click
+  useEffect(() => {
+    if (!isOpen) return;
+    function onPointerDown(e: PointerEvent) {
+      if (containerRef.current && !containerRef.current.contains(e.target as Node)) {
+        close();
+      }
+    }
+    document.addEventListener('pointerdown', onPointerDown);
+    return () => document.removeEventListener('pointerdown', onPointerDown);
+  }, [isOpen, close]);
+
+  // Close on Escape, navigate with keyboard
+  useEffect(() => {
+    if (!isOpen) return;
+    function onKeyDown(e: KeyboardEvent) {
+      if (e.key === 'Escape') close();
+    }
+    document.addEventListener('keydown', onKeyDown);
+    return () => document.removeEventListener('keydown', onKeyDown);
+  }, [isOpen, close]);
+
+  // ── Trigger swatch ─────────────────────────────────────────────────────
+  const triggerSwatch =
+    selectedItem && isColorCategory(selectedItem.category) && selectedItem.resolvedValue
+      ? selectedItem.resolvedValue
+      : null;
+
+  const totalTokenCount = visibleGroups.reduce((n, g) => n + g.tokens.length, 0);
+
+  // ── Render ──────────────────────────────────────────────────────────────
+  return (
+    <div className={css['TokenPicker']} ref={containerRef}>
+      {label && <span className={css['TokenPicker-label']}>{label}</span>}
+
+      {/* Trigger */}
+      <button
+        type="button"
+        className={[css['TokenPicker-trigger'], selectedItem ? css['TokenPicker-trigger--hasValue'] : '']
+          .filter(Boolean)
+          .join(' ')}
+        onClick={open}
+        disabled={disabled}
+        aria-haspopup="listbox"
+        aria-expanded={isOpen}
+        title={selectedItem ? formatTokenLabel(selectedItem.name) : placeholder}
+      >
+        {triggerSwatch && (
+          <span className={css['TokenPicker-swatch']} style={{ background: triggerSwatch }} aria-hidden />
+        )}
+        <span className={css['TokenPicker-triggerText']}>
+          {selectedItem ? formatTokenLabel(selectedItem.name) : placeholder}
+        </span>
+        {selectedItem && onClear && (
+          <button
+            type="button"
+            className={css['TokenPicker-clearBtn']}
+            onClick={handleClear}
+            title="Clear token"
+            aria-label="Clear token selection"
+          >
+            ×
+          </button>
+        )}
+        {!selectedItem && (
+          <span className={css['TokenPicker-chevron']} aria-hidden>
+            ▾
+          </span>
+        )}
+      </button>
+
+      {/* Dropdown */}
+      {isOpen && (
+        <div className={css['TokenPicker-dropdown']} role="listbox">
+          {/* Search */}
+          <div className={css['TokenPicker-searchRow']}>
+            <input
+              ref={searchRef}
+              type="text"
+              className={css['TokenPicker-search']}
+              placeholder="Search tokens..."
+              value={search}
+              onChange={(e) => setSearch(e.target.value)}
+              aria-label="Search tokens"
+            />
+          </div>
+
+          {/* Groups */}
+          <div className={css['TokenPicker-list']}>
+            {totalTokenCount === 0 && <p className={css['TokenPicker-empty']}>No tokens match</p>}
+            {visibleGroups.map((group) => (
+              <div key={group.label} className={css['TokenPicker-group']}>
+                <span className={css['TokenPicker-groupLabel']}>{group.label}</span>
+                {group.tokens.map((item) => {
+                  const isSelected = item.name === selectedToken;
+                  const swatch =
+                    isColorCategory(item.category) && item.resolvedValue && looksLikeColor(item.resolvedValue)
+                      ? item.resolvedValue
+                      : null;
+
+                  return (
+                    <button
+                      key={item.name}
+                      type="button"
+                      role="option"
+                      aria-selected={isSelected}
+                      className={[
+                        css['TokenPicker-option'],
+                        isSelected ? css['TokenPicker-option--active'] : '',
+                        item.isCustom ? css['TokenPicker-option--custom'] : ''
+                      ]
+                        .filter(Boolean)
+                        .join(' ')}
+                      onClick={() => handleSelect(item)}
+                      title={item.description ?? item.resolvedValue ?? item.value}
+                    >
+                      {/* Colour swatch or value preview */}
+                      <span className={css['TokenPicker-optionPreview']} aria-hidden>
+                        {swatch ? (
+                          <span className={css['TokenPicker-optionSwatch']} style={{ background: swatch }} />
+                        ) : (
+                          <span className={css['TokenPicker-optionValueBadge']}>
+                            {(item.resolvedValue ?? item.value).slice(0, 4)}
+                          </span>
+                        )}
+                      </span>
+
+                      <span className={css['TokenPicker-optionBody']}>
+                        <span className={css['TokenPicker-optionName']}>{formatTokenLabel(item.name)}</span>
+                        {item.resolvedValue && (
+                          <span className={css['TokenPicker-optionValue']}>{item.resolvedValue}</span>
+                        )}
+                      </span>
+
+                      {item.isCustom && (
+                        <span className={css['TokenPicker-customBadge']} title="Custom token" aria-hidden>
+                          ★
+                        </span>
+                      )}
+                      {isSelected && (
+                        <span className={css['TokenPicker-checkmark']} aria-hidden>
+                          ✓
+                        </span>
+                      )}
+                    </button>
+                  );
+                })}
+              </div>
+            ))}
+          </div>
+        </div>
+      )}
+    </div>
+  );
+}
diff --git a/packages/noodl-core-ui/src/components/inputs/TokenPicker/index.ts b/packages/noodl-core-ui/src/components/inputs/TokenPicker/index.ts
new file mode 100644
index 0000000..4f4b406
--- /dev/null
+++ b/packages/noodl-core-ui/src/components/inputs/TokenPicker/index.ts
@@ -0,0 +1,2 @@
+export { TokenPicker } from './TokenPicker';
+export type { TokenPickerItem, TokenPickerGroup, TokenPickerProps } from './TokenPicker';
diff --git a/packages/noodl-editor/src/editor/src/contexts/ProjectDesignTokenContext/ProjectDesignTokenContext.tsx b/packages/noodl-editor/src/editor/src/contexts/ProjectDesignTokenContext/ProjectDesignTokenContext.tsx
index 5a10ef6..128a7d3 100644
--- a/packages/noodl-editor/src/editor/src/contexts/ProjectDesignTokenContext/ProjectDesignTokenContext.tsx
+++ b/packages/noodl-editor/src/editor/src/contexts/ProjectDesignTokenContext/ProjectDesignTokenContext.tsx
@@ -8,6 +8,7 @@ import { StyleTokenRecord, StyleTokensModel } from '@noodl-models/StyleTokensMod
 
 import { Slot } from '@noodl-core-ui/types/global';
 
+import { PreviewTokenInjector } from '../../services/PreviewTokenInjector';
 import { DesignTokenColor, extractProjectColors } from './extractProjectColors';
 
 export interface ProjectDesignTokenContext {
@@ -78,6 +79,11 @@ export function ProjectDesignTokenContextProvider({ children }: ProjectDesignTok
     setDesignTokens(styleTokensModel.getTokens());
   }, [styleTokensModel]);
 
+  // Wire preview token injector so the preview webview reflects the current token values
+  useEffect(() => {
+    PreviewTokenInjector.instance.attachModel(styleTokensModel);
+  }, [styleTokensModel]);
+
   useEventListener(styleTokensModel, 'tokensChanged', () => {
     setDesignTokens(styleTokensModel.getTokens());
   });
diff --git a/packages/noodl-editor/src/editor/src/services/PreviewTokenInjector.ts b/packages/noodl-editor/src/editor/src/services/PreviewTokenInjector.ts
new file mode 100644
index 0000000..6bc5cbb
--- /dev/null
+++ b/packages/noodl-editor/src/editor/src/services/PreviewTokenInjector.ts
@@ -0,0 +1,110 @@
+/**
+ * STYLE-001 Phase 4: PreviewTokenInjector
+ *
+ * Injects design token CSS custom properties into the preview webview so that
+ * var(--token-name) references in user projects resolve to the correct values.
+ *
+ * Architecture:
+ * - Singleton service, initialised once at app startup
+ * - CanvasView calls `notifyDomReady(webview)` after each dom-ready event
+ * - Subscribes to StyleTokensModel 'tokensChanged' and re-injects on every change
+ * - Uses `executeJavaScript` to insert/update a <style id="noodl-design-tokens"> in the
+ *   preview's <head>. The style element is created on first injection and updated in place
+ *   on subsequent calls, avoiding repeated DOM mutations.
+ *
+ * CSS escaping:
+ * - The CSS block is passed as a JSON-encoded string inside the script so that backticks,
+ *   backslashes, and dollar signs in token values cannot break template literal parsing.
+ */
+
+import { StyleTokensModel } from '../models/StyleTokensModel';
+
+const STYLE_ELEMENT_ID = 'noodl-design-tokens';
+
+export class PreviewTokenInjector {
+  private static _instance: PreviewTokenInjector | null = null;
+
+  private _webview: Electron.WebviewTag | null = null;
+  private _tokensModel: StyleTokensModel | null = null;
+
+  private constructor() {}
+
+  static get instance(): PreviewTokenInjector {
+    if (!PreviewTokenInjector._instance) {
+      PreviewTokenInjector._instance = new PreviewTokenInjector();
+    }
+    return PreviewTokenInjector._instance;
+  }
+
+  /**
+   * Attach a StyleTokensModel instance. Called once when the project loads.
+   * The injector subscribes to 'tokensChanged' and re-injects whenever tokens change.
+   */
+  attachModel(model: StyleTokensModel): void {
+    // Detach previous model if any — off(context) removes all listeners bound to `this`
+    this._tokensModel?.off(this);
+
+    this._tokensModel = model;
+
+    model.on('tokensChanged', () => this._inject(), this);
+  }
+
+  /**
+   * Called by CanvasView after each dom-ready event (once the session is valid).
+   * Stores the webview reference and immediately injects the current tokens.
+   */
+  notifyDomReady(webview: Electron.WebviewTag): void {
+    this._webview = webview;
+    this._inject();
+  }
+
+  /**
+   * Clear webview reference (e.g. when the canvas is destroyed).
+   */
+  clearWebview(): void {
+    this._webview = null;
+  }
+
+  // ─── Private ─────────────────────────────────────────────────────────────────
+
+  private _inject(): void {
+    if (!this._webview || !this._tokensModel) return;
+
+    const css = this._tokensModel.generateCss();
+    if (!css) return;
+
+    // JSON-encode the CSS to safely pass it through executeJavaScript without
+    // worrying about backticks, backslashes, or $ signs in token values.
+    const encodedCss = JSON.stringify(css);
+
+    const script = `
+      (function() {
+        var id = '${STYLE_ELEMENT_ID}';
+        var el = document.getElementById(id);
+        if (!el) {
+          el = document.createElement('style');
+          el.id = id;
+          (document.head || document.documentElement).appendChild(el);
+        }
+        el.textContent = ${encodedCss};
+      })();
+    `;
+
+    // executeJavaScript returns a Promise — we intentionally don't await it here
+    // because injection is best-effort and we don't want to block the caller.
+    // Errors are swallowed because the webview may navigate away at any time.
+    this._webview.executeJavaScript(script).catch(() => {
+      // Webview navigated or was destroyed — no action needed.
+    });
+  }
+}
+
+/**
+ * One-time initialisation: wire the injector to the global EventDispatcher so it
+ * can pick up the StyleTokensModel when a project loads.
+ *
+ * Call this from the editor bootstrap (e.g. EditorTopBar or App startup).
+ */
+export function initPreviewTokenInjector(tokensModel: StyleTokensModel): void {
+  PreviewTokenInjector.instance.attachModel(tokensModel);
+}
diff --git a/packages/noodl-editor/src/editor/src/views/VisualCanvas/CanvasView.ts b/packages/noodl-editor/src/editor/src/views/VisualCanvas/CanvasView.ts
index b398ccc..12ba6c7 100644
--- a/packages/noodl-editor/src/editor/src/views/VisualCanvas/CanvasView.ts
+++ b/packages/noodl-editor/src/editor/src/views/VisualCanvas/CanvasView.ts
@@ -5,6 +5,7 @@ import { platform } from '@noodl/platform';
 
 import { EventDispatcher } from '../../../../shared/utils/EventDispatcher';
 import View from '../../../../shared/view';
+import { PreviewTokenInjector } from '../../services/PreviewTokenInjector';
 import { VisualCanvas } from './VisualCanvas';
 
 export class CanvasView extends View {
@@ -108,6 +109,9 @@ export class CanvasView extends View {
         this.webview.executeJavaScript(`NoodlEditorHighlightAPI.selectNode('${this.selectedNodeId}')`);
       }
 
+      // Inject project design tokens into the preview so var(--token-name) resolves correctly.
+      PreviewTokenInjector.instance.notifyDomReady(this.webview);
+
       this.updateViewportSize();
     });
 
@@ -180,6 +184,7 @@ export class CanvasView extends View {
       this.root.unmount();
       this.root = null;
     }
+    PreviewTokenInjector.instance.clearWebview();
     ipcRenderer.off('editor-api-response', this._onEditorApiResponse);
   }
   refresh() {