diff --git a/packages/core/src/renderer/components/+catalog/catalog-menu.tsx b/packages/core/src/renderer/components/+catalog/catalog-menu.tsx
index 73121e3b1c..bbbac83ed5 100644
--- a/packages/core/src/renderer/components/+catalog/catalog-menu.tsx
+++ b/packages/core/src/renderer/components/+catalog/catalog-menu.tsx
@@ -16,14 +16,15 @@ import { withInjectables } from "@ogre-tools/injectable-react";
 import filteredCategoriesInjectable from "../../../common/catalog/filtered-categories.injectable";
 import { TreeGroup, TreeItem, TreeView } from "../tree-view/tree-view";
 import { browseCatalogTab } from "./catalog-browse-tab";
+import { HorizontalLine } from "../horizontal-line/horizontal-line";
 
 export interface CatalogMenuProps {
   activeTab: string | undefined;
   onItemClick: (id: string) => void;
 }
 
-function getCategoryIcon(category: CatalogCategory) {
-  const { icon } = category.metadata ?? {};
+function CategoryIcon(props: { category: CatalogCategory }) {
+  const { icon } = props.category.metadata ?? {};
 
   if (typeof icon === "string") {
     return Icon.isSvg(icon)
@@ -42,41 +43,38 @@ const NonInjectedCatalogMenu = observer(({
   activeTab,
   filteredCategories,
   onItemClick,
-}: CatalogMenuProps & Dependencies) => {
-  console.log(treeStyles);
-
-  return (
-    <div className="flex flex-col w-full">
-      <div className={styles.catalog}>Catalog</div>
-      <TreeView>
-        <TreeItem
-          label="Browse"
-          data-testid="*-tab"
-          onClick={() => onItemClick("*")}
-          selected={activeTab === browseCatalogTab} />
-        <TreeGroup
-          classes={treeStyles}
-          label={<div className={styles.parent}>Categories</div>}
-        >
-          {filteredCategories.get()
-            .map(category => (
-              <TreeItem
-                key={category.getId()}
-                label={(
-                  <>
-                    {getCategoryIcon(category)}
-                    <CatalogCategoryLabel category={category} />
-                  </>
-                )}
-                selected={activeTab === category.getId()}
-                data-testid={`${category.getId()}-tab`}
-                onClick={() => onItemClick(category.getId())} />
-            ))}
-        </TreeGroup>
-      </TreeView>
-    </div>
-  );
-});
+}: CatalogMenuProps & Dependencies) => (
+  <div className="flex flex-col w-full">
+    <div className={styles.catalog}>Catalog</div>
+    <TreeView>
+      <TreeItem
+        classes={treeStyles}
+        label="Browse"
+        data-testid="*-tab"
+        onClick={() => onItemClick("*")}
+        selected={activeTab === browseCatalogTab}
+      />
+      <HorizontalLine size="xxs" />
+      <TreeGroup
+        classes={treeStyles}
+        label={<div className={styles.parent}>Categories</div>}
+      >
+        {filteredCategories.get()
+          .map(category => (
+            <TreeItem
+              classes={treeStyles}
+              key={category.getId()}
+              icon={<CategoryIcon category={category} />}
+              label={<CatalogCategoryLabel category={category} />}
+              selected={activeTab === category.getId()}
+              data-testid={`${category.getId()}-tab`}
+              onClick={() => onItemClick(category.getId())}
+            />
+          ))}
+      </TreeGroup>
+    </TreeView>
+  </div>
+));
 
 export const CatalogMenu = withInjectables<Dependencies, CatalogMenuProps>(NonInjectedCatalogMenu, {
   getProps: (di, props) => ({
diff --git a/packages/core/src/renderer/components/+catalog/catalog-tree.module.scss b/packages/core/src/renderer/components/+catalog/catalog-tree.module.scss
index f190d04417..60d595df45 100644
--- a/packages/core/src/renderer/components/+catalog/catalog-tree.module.scss
+++ b/packages/core/src/renderer/components/+catalog/catalog-tree.module.scss
@@ -23,39 +23,8 @@
 .content {
   min-height: 26px;
   line-height: 1.3;
-  padding: 2px var(--padding) 2px 0;
-
-  &:hover {
-    background-color: var(--sidebarItemHoverBackground);
-    border-radius: 2px;
-  }
-
-  &:active {
-    color: white;
-    background-color: var(--blue);
-  }
 }
 
 .group {
   margin-left: 0px;
-
-  .iconContainer {
-    margin-left: 28px;
-    margin-top: 2px;
-    align-self: flex-start;
-  }
-}
-
-.selected {
-  & > *:first-child {
-    background-color: var(--blue);
-    color: white;
-    border-radius: 2px;
-  }
-}
-
-.iconContainer {
-  width: 21px;
-  margin-left: 5px;
-  margin-right: 0;
 }
diff --git a/packages/core/src/renderer/components/+catalog/catalog.tsx b/packages/core/src/renderer/components/+catalog/catalog.tsx
index 42578dcad7..f644e52a2d 100644
--- a/packages/core/src/renderer/components/+catalog/catalog.tsx
+++ b/packages/core/src/renderer/components/+catalog/catalog.tsx
@@ -177,7 +177,6 @@ class NonInjectedCatalog extends React.Component<Dependencies> {
   }
 
   onTabChange = action((tabId: string | null) => {
-    console.log(tabId);
     const activeCategory = this.categories.find(category => category.getId() === tabId);
 
     this.props.emitEvent({
diff --git a/packages/core/src/renderer/components/horizontal-line/horizontal-line.module.scss b/packages/core/src/renderer/components/horizontal-line/horizontal-line.module.scss
index 91dc5106d3..b21c21c62b 100644
--- a/packages/core/src/renderer/components/horizontal-line/horizontal-line.module.scss
+++ b/packages/core/src/renderer/components/horizontal-line/horizontal-line.module.scss
@@ -20,6 +20,9 @@
 
 $baseline: 8px;
 
+@include horizontalLineSize('xxs', 0.5 * $baseline);
+@include horizontalLineSize('xs', 1 * $baseline);
 @include horizontalLineSize('sm', 2 * $baseline);
 @include horizontalLineSize('md', 3 * $baseline);
+@include horizontalLineSize('lg', 4 * $baseline);
 @include horizontalLineSize('xl', 5 * $baseline);
diff --git a/packages/core/src/renderer/components/horizontal-line/horizontal-line.tsx b/packages/core/src/renderer/components/horizontal-line/horizontal-line.tsx
index 107a269b35..63fad2d5ea 100644
--- a/packages/core/src/renderer/components/horizontal-line/horizontal-line.tsx
+++ b/packages/core/src/renderer/components/horizontal-line/horizontal-line.tsx
@@ -7,7 +7,7 @@ import styles from "./horizontal-line.module.scss";
 import { cssNames } from "../../utils";
 
 interface HorizontalLineProps {
-  size?: "sm" | "md" | "xl";
+  size?: "xxs" | "xs" | "sm" | "md" | "lg" | "xl";
 }
 
 export const HorizontalLine = ({ size = "xl" }: HorizontalLineProps = { size: "xl" }) => {
diff --git a/packages/core/src/renderer/components/tree-view/tree-view.module.scss b/packages/core/src/renderer/components/tree-view/tree-view.module.scss
new file mode 100644
index 0000000000..9f54c9ad4d
--- /dev/null
+++ b/packages/core/src/renderer/components/tree-view/tree-view.module.scss
@@ -0,0 +1,63 @@
+.treeItem {
+  display: flex;
+  flex-direction: row;
+  padding: 2px var(--padding) 2px 0;
+  cursor: pointer;
+
+  &:hover {
+    background-color: var(--sidebarItemHoverBackground);
+  }
+
+  &.selected:hover {
+    background-color: var(--blue);
+  }
+}
+
+.selected {
+  background-color: var(--blue);
+  color: white;
+  border-radius: 2px;
+  width: 100%;
+}
+
+.treeGroup {
+  display: flex;
+  flex-direction: column;
+  cursor: pointer;
+}
+
+.contents {
+  padding-left: 25px;
+  transition: all 300ms ease;
+  overflow: hidden;
+
+  &.expanded {
+    max-height: 100%;
+  }
+
+  &:not(.expanded) {
+    max-height: 0;
+  }
+}
+
+.selected {
+  color: white;
+  background-color: var(--blue);
+}
+
+.group {
+  display: flex;
+  flex-direction: row;
+}
+
+.iconContainer {
+  align-self: flex-start;
+  width: 21px;
+  margin-left: 5px;
+  margin-right: 5px;
+}
+
+.treeView {
+  display: flex;
+  flex-direction: column;
+}
diff --git a/packages/core/src/renderer/components/tree-view/tree-view.tsx b/packages/core/src/renderer/components/tree-view/tree-view.tsx
index 1063f50588..63bfc34de3 100644
--- a/packages/core/src/renderer/components/tree-view/tree-view.tsx
+++ b/packages/core/src/renderer/components/tree-view/tree-view.tsx
@@ -3,6 +3,7 @@
  * Licensed under MIT License. See LICENSE in root directory for more information.
  */
 
+import styles from "./tree-view.module.scss";
 import type { MouseEventHandler } from "react";
 import React, { useState } from "react";
 import { cssNames } from "../../utils";
@@ -20,7 +21,7 @@ export interface TreeViewProps {
 export function TreeView(props: TreeViewProps) {
   return (
     <ul
-      className={props.classes?.root}
+      className={cssNames(props.classes?.root, styles.treeView)}
       role="tree"
     >
       {props.children}
@@ -31,10 +32,14 @@ export function TreeView(props: TreeViewProps) {
 export interface TreeItemClasses {
   root?: string;
   label?: string;
+  selected?: string;
+  hover?: string;
+  iconContainer?: string;
 }
 
 export interface TreeItemProps {
   classes?: TreeItemClasses;
+  icon?: JSX.Element;
   label: JSX.Element | string;
   testId?: string;
   selected?: boolean;
@@ -42,15 +47,31 @@ export interface TreeItemProps {
 }
 
 export function TreeItem(props: TreeItemProps) {
+  const [hovering, setHovering] = useState(false);
+  const optionalCssNames: Partial<Record<string, any>> = {};
+
+  if (props.classes?.selected) {
+    optionalCssNames[props.classes.selected] = props.selected ?? false;
+  }
+
+  if (props.classes?.hover) {
+    optionalCssNames[props.classes.hover] = hovering;
+  }
+
   return (
     <li
-      className={cssNames(props.classes?.root, {
-        selected: props.selected ?? false,
+      className={cssNames(props.classes?.root, optionalCssNames, styles.treeItem, {
+        [styles.selected]: props.selected ?? false,
       })}
       role="treeitem"
       data-testid={props.testId}
       onClick={props.onClick}
+      onMouseOver={() => setHovering(true)}
+      onMouseLeave={() => setHovering(false)}
     >
+      <div className={cssNames(props.classes?.iconContainer, styles.iconContainer)}>
+        {props.icon}
+      </div>
       <div className={props.classes?.label}>
         {props.label}
       </div>
@@ -60,7 +81,7 @@ export function TreeItem(props: TreeItemProps) {
 
 export interface TreeGroupClasses {
   root?: string;
-  header?: string;
+  group?: string;
   iconContainer?: string;
   label?: string;
   contents?: string;
@@ -81,12 +102,15 @@ export function TreeGroup(props: TreeGroupProps) {
 
   return (
     <li
-      className={props.classes?.root}
+      className={cssNames(props.classes?.root, styles.treeGroup)}
       role="group"
       data-testid={props.testId}
     >
-      <div className={props.classes?.header} onClick={() => setExpanded(!expanded)}>
-        <div className={props.classes?.iconContainer}>
+      <div
+        className={cssNames(props.classes?.group, styles.group)}
+        onClick={() => setExpanded(!expanded)}
+      >
+        <div className={cssNames(props.classes?.iconContainer, styles.iconContainer)}>
           {
             expanded
               ? props.collapseIcon ?? <Icon material="expand_more" />
@@ -97,13 +121,13 @@ export function TreeGroup(props: TreeGroupProps) {
           {props.label}
         </div>
       </div>
-      <div className={props.classes?.contents}>
-        {
-          expanded
-            ? props.children
-            : null
-        }
-      </div>
+      <ul
+        className={cssNames(props.classes?.contents, styles.contents, {
+          [styles.expanded]: expanded,
+        })}
+      >
+        {props.children}
+      </ul>
     </li>
   );
 }
diff --git a/tsconfig.json b/tsconfig.json
index 87d282e152..38419a76b6 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -21,7 +21,6 @@
     "skipLibCheck": true,
     "allowJs": false,
     "esModuleInterop": true,
-    "allowSyntheticDefaultImports": true,
     "importsNotUsedAsValues": "error",
     "traceResolution": false,
     "resolveJsonModule": true,