diff --git a/core/bubbles/bubble.ts b/core/bubbles/bubble.ts
index 35b9e7dde0a..cac1c648528 100644
--- a/core/bubbles/bubble.ts
+++ b/core/bubbles/bubble.ts
@@ -106,11 +106,7 @@ export abstract class Bubble implements IBubble, ISelectable {
     );
     const embossGroup = dom.createSvgElement(
       Svg.G,
-      {
-        'filter': `url(#${
-          this.workspace.getRenderer().getConstants().embossFilterId
-        })`,
-      },
+      {'class': 'blocklyEmboss'},
       this.svgRoot,
     );
     this.tail = dom.createSvgElement(
diff --git a/core/css.ts b/core/css.ts
index 0c547ca0a95..fe507141167 100644
--- a/core/css.ts
+++ b/core/css.ts
@@ -85,6 +85,10 @@ let content = `
   transition: transform .5s;
 }
 
+.blocklyEmboss {
+  filter: var(--blocklyEmbossFilter);
+}
+
 .blocklyTooltipDiv {
   background-color: #ffffc7;
   border: 1px solid #ddc;
@@ -138,6 +142,10 @@ let content = `
   border-color: inherit;
 }
 
+.blocklyHighlighted>.blocklyPath {
+  filter: var(--blocklyEmbossFilter);
+}
+
 .blocklyHighlightedConnectionPath {
   fill: none;
   stroke: #fc3;
@@ -189,6 +197,7 @@ let content = `
 }
 
 .blocklyDisabled>.blocklyPath {
+  fill: var(--blocklyDisabledPattern);
   fill-opacity: .5;
   stroke-opacity: .5;
 }
diff --git a/core/grid.ts b/core/grid.ts
index 1a5de250e5c..45c1674f9b7 100644
--- a/core/grid.ts
+++ b/core/grid.ts
@@ -210,6 +210,9 @@ export class Grid {
    * @param rnd A random ID to append to the pattern's ID.
    * @param gridOptions The object containing grid configuration.
    * @param defs The root SVG element for this workspace's defs.
+   * @param injectionDiv The div containing the parent workspace and all related
+   *   workspaces and block containers. CSS variables representing SVG patterns
+   *   will be scoped to this container.
    * @returns The SVG element for the grid pattern.
    * @internal
    */
@@ -217,6 +220,7 @@ export class Grid {
     rnd: string,
     gridOptions: GridOptions,
     defs: SVGElement,
+    injectionDiv?: HTMLElement,
   ): SVGElement {
     /*
           <pattern id="blocklyGridPattern837493" patternUnits="userSpaceOnUse">
@@ -247,6 +251,17 @@ export class Grid {
       // Edge 16 doesn't handle empty patterns
       dom.createSvgElement(Svg.LINE, {}, gridPattern);
     }
+
+    if (injectionDiv) {
+      // Add CSS variables scoped to the injection div referencing the created
+      // patterns so that CSS can apply the patterns to any element in the
+      // injection div.
+      injectionDiv.style.setProperty(
+        '--blocklyGridPattern',
+        `url(#${gridPattern.id})`,
+      );
+    }
+
     return gridPattern;
   }
 }
diff --git a/core/inject.ts b/core/inject.ts
index 55409b7f3d2..d04b23ed766 100644
--- a/core/inject.ts
+++ b/core/inject.ts
@@ -89,7 +89,7 @@ export function inject(
  * @param options Dictionary of options.
  * @returns Newly created SVG image.
  */
-function createDom(container: Element, options: Options): SVGElement {
+function createDom(container: HTMLElement, options: Options): SVGElement {
   // Sadly browsers (Chrome vs Firefox) are currently inconsistent in laying
   // out content in RTL mode.  Therefore Blockly forces the use of LTR,
   // then manually positions content in RTL as needed.
@@ -132,7 +132,12 @@ function createDom(container: Element, options: Options): SVGElement {
   // https://neil.fraser.name/news/2015/11/01/
   const rnd = String(Math.random()).substring(2);
 
-  options.gridPattern = Grid.createDom(rnd, options.gridOptions, defs);
+  options.gridPattern = Grid.createDom(
+    rnd,
+    options.gridOptions,
+    defs,
+    container,
+  );
   return svg;
 }
 
@@ -144,7 +149,7 @@ function createDom(container: Element, options: Options): SVGElement {
  * @returns Newly created main workspace.
  */
 function createMainWorkspace(
-  injectionDiv: Element,
+  injectionDiv: HTMLElement,
   svg: SVGElement,
   options: Options,
 ): WorkspaceSvg {
diff --git a/core/renderers/common/constants.ts b/core/renderers/common/constants.ts
index 01217edb725..c5a7a759c5c 100644
--- a/core/renderers/common/constants.ts
+++ b/core/renderers/common/constants.ts
@@ -926,8 +926,18 @@ export class ConstantProvider {
    * @param svg The root of the workspace's SVG.
    * @param tagName The name to use for the CSS style tag.
    * @param selector The CSS selector to use.
+   * @param injectionDivIfIsParent The div containing the parent workspace and
+   *   all related workspaces and block containers, if this renderer is for the
+   *   parent workspace. CSS variables representing SVG patterns will be scoped
+   *   to this container. Child workspaces should not override the CSS variables
+   *   created by the parent and thus do not need access to the injection div.
    */
-  createDom(svg: SVGElement, tagName: string, selector: string) {
+  createDom(
+    svg: SVGElement,
+    tagName: string,
+    selector: string,
+    injectionDivIfIsParent?: HTMLElement,
+  ) {
     this.injectCSS_(tagName, selector);
 
     /*
@@ -1034,6 +1044,24 @@ export class ConstantProvider {
     this.disabledPattern = disabledPattern;
 
     this.createDebugFilter();
+
+    if (injectionDivIfIsParent) {
+      // If this renderer is for the parent workspace, add CSS variables scoped
+      // to the injection div referencing the created patterns so that CSS can
+      // apply the patterns to any element in the injection div.
+      injectionDivIfIsParent.style.setProperty(
+        '--blocklyEmbossFilter',
+        `url(#${this.embossFilterId})`,
+      );
+      injectionDivIfIsParent.style.setProperty(
+        '--blocklyDisabledPattern',
+        `url(#${this.disabledPatternId})`,
+      );
+      injectionDivIfIsParent.style.setProperty(
+        '--blocklyDebugFilter',
+        `url(#${this.debugFilterId})`,
+      );
+    }
   }
 
   /**
diff --git a/core/renderers/common/path_object.ts b/core/renderers/common/path_object.ts
index 12e23b6c4aa..823ab678525 100644
--- a/core/renderers/common/path_object.ts
+++ b/core/renderers/common/path_object.ts
@@ -173,13 +173,8 @@ export class PathObject implements IPathObject {
 
   updateHighlighted(enable: boolean) {
     if (enable) {
-      this.svgPath.setAttribute(
-        'filter',
-        'url(#' + this.constants.embossFilterId + ')',
-      );
       this.setClass_('blocklyHighlighted', true);
     } else {
-      this.svgPath.setAttribute('filter', 'none');
       this.setClass_('blocklyHighlighted', false);
     }
   }
@@ -206,12 +201,6 @@ export class PathObject implements IPathObject {
    */
   protected updateDisabled_(disabled: boolean) {
     this.setClass_('blocklyDisabled', disabled);
-    if (disabled) {
-      this.svgPath.setAttribute(
-        'fill',
-        'url(#' + this.constants.disabledPatternId + ')',
-      );
-    }
   }
 
   /**
diff --git a/core/renderers/common/renderer.ts b/core/renderers/common/renderer.ts
index 255bc81ff52..62d392a8bd5 100644
--- a/core/renderers/common/renderer.ts
+++ b/core/renderers/common/renderer.ts
@@ -78,13 +78,23 @@ export class Renderer implements IRegistrable {
    *
    * @param svg The root of the workspace's SVG.
    * @param theme The workspace theme object.
+   * @param injectionDivIfIsParent The div containing the parent workspace and
+   *   all related workspaces and block containers, if this renderer is for the
+   *   parent workspace. CSS variables representing SVG patterns will be scoped
+   *   to this container. Child workspaces should not override the CSS variables
+   *   created by the parent and thus do not need access to the injection div.
    * @internal
    */
-  createDom(svg: SVGElement, theme: Theme) {
+  createDom(
+    svg: SVGElement,
+    theme: Theme,
+    injectionDivIfIsParent?: HTMLElement,
+  ) {
     this.constants_.createDom(
       svg,
       this.name + '-' + theme.name,
       '.' + this.getClassName() + '.' + theme.getClassName(),
+      injectionDivIfIsParent,
     );
   }
 
@@ -93,8 +103,17 @@ export class Renderer implements IRegistrable {
    *
    * @param svg The root of the workspace's SVG.
    * @param theme The workspace theme object.
-   */
-  refreshDom(svg: SVGElement, theme: Theme) {
+   * @param injectionDivIfIsParent The div containing the parent workspace and
+   *   all related workspaces and block containers, if this renderer is for the
+   *   parent workspace. CSS variables representing SVG patterns will be scoped
+   *   to this container. Child workspaces should not override the CSS variables
+   *   created by the parent and thus do not need access to the injection div.
+   */
+  refreshDom(
+    svg: SVGElement,
+    theme: Theme,
+    injectionDivIfIsParent?: HTMLElement,
+  ) {
     const previousConstants = this.getConstants();
     previousConstants.dispose();
     this.constants_ = this.makeConstants_();
@@ -105,7 +124,7 @@ export class Renderer implements IRegistrable {
     this.constants_.randomIdentifier = previousConstants.randomIdentifier;
     this.constants_.setTheme(theme);
     this.constants_.init();
-    this.createDom(svg, theme);
+    this.createDom(svg, theme, injectionDivIfIsParent);
   }
 
   /**
diff --git a/core/renderers/geras/renderer.ts b/core/renderers/geras/renderer.ts
index 06062e9bc30..635391c8128 100644
--- a/core/renderers/geras/renderer.ts
+++ b/core/renderers/geras/renderer.ts
@@ -50,8 +50,12 @@ export class Renderer extends BaseRenderer {
     this.highlightConstants.init();
   }
 
-  override refreshDom(svg: SVGElement, theme: Theme) {
-    super.refreshDom(svg, theme);
+  override refreshDom(
+    svg: SVGElement,
+    theme: Theme,
+    injectionDiv: HTMLElement,
+  ) {
+    super.refreshDom(svg, theme, injectionDiv);
     this.getHighlightConstants().init();
   }
 
diff --git a/core/renderers/zelos/constants.ts b/core/renderers/zelos/constants.ts
index 213d8a25967..3677d347792 100644
--- a/core/renderers/zelos/constants.ts
+++ b/core/renderers/zelos/constants.ts
@@ -675,8 +675,13 @@ export class ConstantProvider extends BaseConstantProvider {
     return utilsColour.blend('#000', colour, 0.25) || colour;
   }
 
-  override createDom(svg: SVGElement, tagName: string, selector: string) {
-    super.createDom(svg, tagName, selector);
+  override createDom(
+    svg: SVGElement,
+    tagName: string,
+    selector: string,
+    injectionDivIfIsParent?: HTMLElement,
+  ) {
+    super.createDom(svg, tagName, selector, injectionDivIfIsParent);
     /*
         <defs>
           ... filters go here ...
@@ -795,6 +800,20 @@ export class ConstantProvider extends BaseConstantProvider {
     );
     this.replacementGlowFilterId = replacementGlowFilter.id;
     this.replacementGlowFilter = replacementGlowFilter;
+
+    if (injectionDivIfIsParent) {
+      // If this renderer is for the parent workspace, add CSS variables scoped
+      // to the injection div referencing the created patterns so that CSS can
+      // apply the patterns to any element in the injection div.
+      injectionDivIfIsParent.style.setProperty(
+        '--blocklySelectedGlowFilter',
+        `url(#${this.selectedGlowFilterId})`,
+      );
+      injectionDivIfIsParent.style.setProperty(
+        '--blocklyReplacementGlowFilter',
+        `url(#${this.replacementGlowFilterId})`,
+      );
+    }
   }
 
   override getCSS_(selector: string) {
@@ -873,7 +892,7 @@ export class ConstantProvider extends BaseConstantProvider {
 
       // Disabled outline paths.
       `${selector} .blocklyDisabled > .blocklyOutlinePath {`,
-      `fill: url(#blocklyDisabledPattern${this.randomIdentifier})`,
+      `fill: var(--blocklyDisabledPattern)`,
       `}`,
 
       // Insertion marker.
@@ -881,6 +900,15 @@ export class ConstantProvider extends BaseConstantProvider {
       `fill-opacity: ${this.INSERTION_MARKER_OPACITY};`,
       `stroke: none;`,
       `}`,
+
+      `${selector} .blocklySelected>.blocklyPath.blocklyPathSelected {`,
+      `fill: none;`,
+      `filter: var(--blocklySelectedGlowFilter);`,
+      `}`,
+
+      `${selector} .blocklyReplaceable>.blocklyPath {`,
+      `filter: var(--blocklyReplacementGlowFilter);`,
+      `}`,
     ];
   }
 }
diff --git a/core/renderers/zelos/path_object.ts b/core/renderers/zelos/path_object.ts
index fdc6ab8a626..6cb3a0506ef 100644
--- a/core/renderers/zelos/path_object.ts
+++ b/core/renderers/zelos/path_object.ts
@@ -91,11 +91,7 @@ export class PathObject extends BasePathObject {
     if (enable) {
       if (!this.svgPathSelected) {
         this.svgPathSelected = this.svgPath.cloneNode(true) as SVGElement;
-        this.svgPathSelected.setAttribute('fill', 'none');
-        this.svgPathSelected.setAttribute(
-          'filter',
-          'url(#' + this.constants.selectedGlowFilterId + ')',
-        );
+        this.svgPathSelected.classList.add('blocklyPathSelected');
         this.svgRoot.appendChild(this.svgPathSelected);
       }
     } else {
@@ -108,14 +104,6 @@ export class PathObject extends BasePathObject {
 
   override updateReplacementFade(enable: boolean) {
     this.setClass_('blocklyReplaceable', enable);
-    if (enable) {
-      this.svgPath.setAttribute(
-        'filter',
-        'url(#' + this.constants.replacementGlowFilterId + ')',
-      );
-    } else {
-      this.svgPath.removeAttribute('filter');
-    }
   }
 
   override updateShapeForInputHighlight(conn: Connection, enable: boolean) {
diff --git a/core/workspace_svg.ts b/core/workspace_svg.ts
index 5447bdf51b8..30dcaaeb9a9 100644
--- a/core/workspace_svg.ts
+++ b/core/workspace_svg.ts
@@ -225,7 +225,7 @@ export class WorkspaceSvg extends Workspace implements IASTNodeLocationSvg {
    * The first parent div with 'injectionDiv' in the name, or null if not set.
    * Access this with getInjectionDiv.
    */
-  private injectionDiv: Element | null = null;
+  private injectionDiv: HTMLElement | null = null;
 
   /**
    * Last known position of the page scroll.
@@ -539,7 +539,12 @@ export class WorkspaceSvg extends Workspace implements IASTNodeLocationSvg {
    */
   refreshTheme() {
     if (this.svgGroup_) {
-      this.renderer.refreshDom(this.svgGroup_, this.getTheme());
+      const isParentWorkspace = this.options.parentWorkspace === null;
+      this.renderer.refreshDom(
+        this.svgGroup_,
+        this.getTheme(),
+        isParentWorkspace ? this.getInjectionDiv() : undefined,
+      );
     }
 
     // Update all blocks in workspace that have a style name.
@@ -636,20 +641,24 @@ export class WorkspaceSvg extends Workspace implements IASTNodeLocationSvg {
       // Before the SVG canvas, scale the coordinates.
       scale = this.scale;
     }
+    let ancestor: Element = element;
     do {
       // Loop through this block and every parent.
-      const xy = svgMath.getRelativeXY(element);
-      if (element === this.getCanvas() || element === this.getBubbleCanvas()) {
+      const xy = svgMath.getRelativeXY(ancestor);
+      if (
+        ancestor === this.getCanvas() ||
+        ancestor === this.getBubbleCanvas()
+      ) {
         // After the SVG canvas, don't scale the coordinates.
         scale = 1;
       }
       x += xy.x * scale;
       y += xy.y * scale;
-      element = element.parentNode as SVGElement;
+      ancestor = ancestor.parentNode as Element;
     } while (
-      element &&
-      element !== this.getParentSvg() &&
-      element !== this.getInjectionDiv()
+      ancestor &&
+      ancestor !== this.getParentSvg() &&
+      ancestor !== this.getInjectionDiv()
     );
     return new Coordinate(x, y);
   }
@@ -687,7 +696,7 @@ export class WorkspaceSvg extends Workspace implements IASTNodeLocationSvg {
    * @returns The first parent div with 'injectionDiv' in the name.
    * @internal
    */
-  getInjectionDiv(): Element {
+  getInjectionDiv(): HTMLElement {
     // NB: it would be better to pass this in at createDom, but is more likely
     // to break existing uses of Blockly.
     if (!this.injectionDiv) {
@@ -695,7 +704,7 @@ export class WorkspaceSvg extends Workspace implements IASTNodeLocationSvg {
       while (element) {
         const classes = element.getAttribute('class') || '';
         if ((' ' + classes + ' ').includes(' injectionDiv ')) {
-          this.injectionDiv = element;
+          this.injectionDiv = element as HTMLElement;
           break;
         }
         element = element.parentNode as Element;
@@ -739,7 +748,7 @@ export class WorkspaceSvg extends Workspace implements IASTNodeLocationSvg {
    *     'blocklyMutatorBackground'.
    * @returns The workspace's SVG group.
    */
-  createDom(opt_backgroundClass?: string, injectionDiv?: Element): Element {
+  createDom(opt_backgroundClass?: string, injectionDiv?: HTMLElement): Element {
     if (!this.injectionDiv) {
       this.injectionDiv = injectionDiv ?? null;
     }
@@ -765,8 +774,7 @@ export class WorkspaceSvg extends Workspace implements IASTNodeLocationSvg {
       );
 
       if (opt_backgroundClass === 'blocklyMainBackground' && this.grid) {
-        this.svgBackground_.style.fill =
-          'url(#' + this.grid.getPatternId() + ')';
+        this.svgBackground_.style.fill = 'var(--blocklyGridPattern)';
       } else {
         this.themeManager_.subscribe(
           this.svgBackground_,
@@ -823,7 +831,12 @@ export class WorkspaceSvg extends Workspace implements IASTNodeLocationSvg {
 
     CursorClass && this.markerManager.setCursor(new CursorClass());
 
-    this.renderer.createDom(this.svgGroup_, this.getTheme());
+    const isParentWorkspace = this.options.parentWorkspace === null;
+    this.renderer.createDom(
+      this.svgGroup_,
+      this.getTheme(),
+      isParentWorkspace ? this.getInjectionDiv() : undefined,
+    );
     return this.svgGroup_;
   }