diff --git a/src/app/shared/sass-helper/css-variable.actions.ts b/src/app/shared/sass-helper/css-variable.actions.ts
index 93225f9426..2d58a2978b 100644
--- a/src/app/shared/sass-helper/css-variable.actions.ts
+++ b/src/app/shared/sass-helper/css-variable.actions.ts
@@ -1,3 +1,4 @@
+/* eslint-disable max-classes-per-file */
 import { Action } from '@ngrx/store';
 import { type } from '../ngrx/type';
 import { KeyValuePair } from '../key-value-pair.model';
@@ -38,9 +39,6 @@ export class AddAllCSSVariablesAction implements Action {
 
 export class ClearCSSVariablesAction implements Action {
   type = CSSVariableActionTypes.CLEAR;
-
-  constructor() {
-  }
 }
 
 export type CSSVariableAction = AddCSSVariableAction | AddAllCSSVariablesAction | ClearCSSVariablesAction;
diff --git a/src/app/shared/sass-helper/css-variable.reducer.ts b/src/app/shared/sass-helper/css-variable.reducer.ts
index 405cbf5df4..449a936b4e 100644
--- a/src/app/shared/sass-helper/css-variable.reducer.ts
+++ b/src/app/shared/sass-helper/css-variable.reducer.ts
@@ -19,7 +19,7 @@ export function cssVariablesReducer(state = initialState, action: CSSVariableAct
       return Object.assign({}, state, { [variable.name]: variable.value });
     } case CSSVariableActionTypes.ADD_ALL: {
       const variables = action.payload;
-      return Object.assign({}, state, ...variables.map(({ key, value }: KeyValuePair<string, string>) => {return {[key]: value}}));
+      return Object.assign({}, state, ...variables.map(({ key, value }: KeyValuePair<string, string>) => {return {[key]: value};}));
     } case CSSVariableActionTypes.CLEAR: {
       return initialState;
     }
diff --git a/src/app/shared/sass-helper/css-variable.service.ts b/src/app/shared/sass-helper/css-variable.service.ts
index 9ba9dfca3c..af40c634fd 100644
--- a/src/app/shared/sass-helper/css-variable.service.ts
+++ b/src/app/shared/sass-helper/css-variable.service.ts
@@ -87,8 +87,7 @@ export class CSSVariableService {
    * @return array<KeyValuePair<string, string>>
    * ex; [{key: "--color-accent", value: "#b9f500"}, {key: "--color-text", value: "#252525"}, ...]
    */
-  getCSSVariablesFromStylesheets(document: Document): KeyValuePair<string, string>[]
-  {
+  getCSSVariablesFromStylesheets(document: Document): KeyValuePair<string, string>[] {
     // styleSheets is array-like, so we convert it to an array.
     // Filter out any stylesheets not on this domain
     return [...document.styleSheets]
diff --git a/src/app/shared/testing/css-variable-service.stub.ts b/src/app/shared/testing/css-variable-service.stub.ts
index f72e338455..47be5c0ff4 100644
--- a/src/app/shared/testing/css-variable-service.stub.ts
+++ b/src/app/shared/testing/css-variable-service.stub.ts
@@ -1,4 +1,5 @@
 import { Observable, of as observableOf } from 'rxjs';
+import { KeyValuePair } from '../key-value-pair.model';
 
 const variables = {
   '--bs-sm-min': '576px,',
@@ -19,4 +20,16 @@ export class CSSVariableServiceStub {
   addCSSVariable(name: string, value: string): void {
     /**/
   }
+
+  addCSSVariables(variables: KeyValuePair<string, string>[]): void {
+    /**/
+  }
+
+  clearCSSVariables(): void {
+    /**/
+  }
+
+  getCSSVariablesFromStylesheets(document: Document): void {
+    /**/
+  }
 }
diff --git a/src/modules/app/server-init.service.ts b/src/modules/app/server-init.service.ts
index e93c692cd7..9f6aa65921 100644
--- a/src/modules/app/server-init.service.ts
+++ b/src/modules/app/server-init.service.ts
@@ -18,7 +18,7 @@ import { LocaleService } from '../../app/core/locale/locale.service';
 import { Angulartics2DSpace } from '../../app/statistics/angulartics/dspace-provider';
 import { MetadataService } from '../../app/core/metadata/metadata.service';
 import { BreadcrumbsService } from '../../app/breadcrumbs/breadcrumbs.service';
-import { CSSVariableService } from '../../app/shared/sass-helper/sass-helper.service';
+import { CSSVariableService } from '../../sass-helper/css-variable.service';
 import { ThemeService } from '../../app/shared/theme-support/theme.service';
 import { take } from 'rxjs/operators';