diff --git a/src/Layout.tsx b/src/Layout.tsx
index 23fb1d7e..db4a69c7 100644
--- a/src/Layout.tsx
+++ b/src/Layout.tsx
@@ -16,6 +16,7 @@ export { scrollFadeMask }
 
 import React from 'react'
 import { getNavItemsWithComputed, NavItem, NavItemComponent } from './NavItemComponent.js'
+import { Collapsible } from './MenuModal/Collapsible.js'
 import { parseMarkdownMini } from './parseMarkdownMini.js'
 import { usePageContext } from './renderer/usePageContext.js'
 import { ExternalLinks } from './ExternalLinks.js'
@@ -135,6 +136,7 @@ function LayoutDocsPage({ children }: { children: React.ReactNode }) {
   }
   #nav-left {
     min-width: ${navLeftWidthMax + blockMargin}px;
+    transition: width 0.3s ease;
   }
 }
 .page-content {
@@ -265,24 +267,57 @@ function getStyleNavLeft() {
 }`
 }
 
-function NavigationContent(props: {
-  navItems: NavItem[]
-  showOnlyRelevant?: true
-}) {
+function NavigationContent(props: { navItems: NavItem[]; showOnlyRelevant?: true }) {
   const pageContext = usePageContext()
   const navItemsWithComputed = getNavItemsWithComputed(props.navItems, pageContext.urlPathname)
 
-  let navItemsRelevant = navItemsWithComputed
-  if (props.showOnlyRelevant) navItemsRelevant = navItemsRelevant.filter((navItemGroup) => navItemGroup.isRelevant)
-  const navContent = navItemsRelevant.map((navItem, i) => <NavItemComponent navItem={navItem} key={i} />)
+  if (props.showOnlyRelevant) {
+    const sections = groupBySections(navItemsWithComputed)
+    return (
+      <div className="navigation-content" style={{ marginTop: 10 }}>
+        {sections.map((section, i) => (
+          <Collapsible
+            key={i}
+            head={(onClick) => <NavItemComponent navItem={section.level1} onClick={onClick} />}
+            disabled={false}
+            collapsedInit={!section.level1.isRelevant}
+          >
+            {section.children.map((navItem, j) => (
+              <NavItemComponent key={j} navItem={navItem} />
+            ))}
+          </Collapsible>
+        ))}
+      </div>
+    )
+  }
 
   return (
     <div className="navigation-content" style={{ marginTop: 10 }}>
-      {navContent}
+      {navItemsWithComputed.map((navItem, i) => (
+        <NavItemComponent key={i} navItem={navItem} />
+      ))}
     </div>
   )
 }
 
+type NavItemsSection = {
+  level1: ReturnType<typeof getNavItemsWithComputed>[number]
+  children: ReturnType<typeof getNavItemsWithComputed>
+}
+function groupBySections(navItems: ReturnType<typeof getNavItemsWithComputed>): NavItemsSection[] {
+  const sections: NavItemsSection[] = []
+  let current: NavItemsSection | null = null
+  for (const navItem of navItems) {
+    if (navItem.level === 1) {
+      current = { level1: navItem, children: [] }
+      sections.push(current)
+    } else if (current) {
+      current.children.push(navItem)
+    }
+  }
+  return sections
+}
+
 function isNavLeftAlwaysHidden() {
   const pageContext = usePageContext()
   const { isLandingPage, navItemsDetached, pageDesign } = pageContext.resolved
diff --git a/src/MenuModal/Collapsible.tsx b/src/MenuModal/Collapsible.tsx
index d99af5ed..06c2a3e5 100644
--- a/src/MenuModal/Collapsible.tsx
+++ b/src/MenuModal/Collapsible.tsx
@@ -25,7 +25,7 @@ function Collapsible({
     if (!disabled) {
       setIsAnimating(true)
       if (!collapsed) {
-        // If expanding, set height to current scroll height before animation
+        // If collapsing, set height to current scroll height before animation
         contentRef.current!.style.height = `${contentRef.current!.scrollHeight}px`
         // Force a reflow
         contentRef.current!.offsetHeight
@@ -34,8 +34,8 @@ function Collapsible({
     }
   }
 
-  const onTransitionEnd = () => {
-    setIsAnimating(false)
+  const onTransitionEnd = (e: React.TransitionEvent) => {
+    if (e.propertyName === 'height') setIsAnimating(false)
   }
 
   const showContent = disabled ? true : !collapsed
@@ -50,6 +50,7 @@ function Collapsible({
         onTransitionEnd={onTransitionEnd}
         style={{
           height: !showContent ? 0 : isAnimating ? contentRef.current!.scrollHeight : 'auto',
+          width: !showContent ? 0 : 'auto',
           overflow: 'hidden',
           transition: 'none 0.3s ease',
           transitionProperty: 'height, margin-bottom',
@@ -57,7 +58,7 @@ function Collapsible({
         }}
         aria-expanded={showContent}
       >
-        {children}
+        <div style={{ minWidth: 'max-content' }}>{children}</div>
       </div>
     </div>
   )
diff --git a/src/NavItemComponent.css b/src/NavItemComponent.css
index fe673bf9..405723d7 100644
--- a/src/NavItemComponent.css
+++ b/src/NavItemComponent.css
@@ -53,10 +53,12 @@
     }
   }
   #nav-left & {
-    border-bottom: 3px solid var(--color-category);
-    padding-bottom: 2px;
     margin-top: 3px;
     margin-bottom: 10px;
+    .nav-item-title {
+      border-bottom: 3px solid var(--color-category);
+      padding-bottom: 2px;
+    }
   }
 }
 .nav-item-level-2 {
@@ -110,6 +112,8 @@
 
 #nav-left {
   .nav-item-level-1 {
+    display: flex;
+    cursor: pointer;
     margin-left: min(25px, max(5px, 30 * (1vw - 12.7px) - 5px));
   }
   .nav-head-logo {
@@ -120,4 +124,9 @@
   .nav-item-level-4 {
     padding-left: min(30px, max(8px, 30 * (1vw - 12.7px)));
   }
+  .collapsible-icon {
+    position: static;
+    margin-left: auto;
+    padding-left: 6px;
+  }
 }
diff --git a/src/NavItemComponent.tsx b/src/NavItemComponent.tsx
index 43993908..56ad7da1 100644
--- a/src/NavItemComponent.tsx
+++ b/src/NavItemComponent.tsx
@@ -93,8 +93,10 @@ function NavItemComponent({
   if (navItem.level === 1) {
     children = (
       <>
-        {icon}
-        {children}
+        <span className="nav-item-title">
+          {icon}
+          {children}
+        </span>
         <Chevron className="collapsible-icon" height={9} />
       </>
     )