diff --git a/packages/gitbook/src/components/SiteSections/SiteSectionTabs.tsx b/packages/gitbook/src/components/SiteSections/SiteSectionTabs.tsx
index 97b94a2ed..341a2c698 100644
--- a/packages/gitbook/src/components/SiteSections/SiteSectionTabs.tsx
+++ b/packages/gitbook/src/components/SiteSections/SiteSectionTabs.tsx
@@ -17,9 +17,13 @@ import type {
     ClientSiteSections,
 } from './encodeClientSiteSections';
 
+const DESKTOP_BREAKPOINT = 768;
 const SCREEN_OFFSET = 16; // 1rem
 const MAX_ITEMS_PER_COLUMN = 10; // number of items per column
-const GROUP_MASONRY_THRESHOLD = 6; // if a section group has more than this many child groups, it will be shown in a masonry grid
+const GROUP_MASONRY_THRESHOLD = 3; // if a section group has more than this many child groups, it will be shown in a masonry grid
+const COLUMN_WIDTH = '18rem';
+const COLUMN_GAP = '2rem';
+const MAX_MASONRY_COLUMNS = 4;
 
 /**
  * A set of navigational links representing site sections for multi-section sites
@@ -37,24 +41,19 @@ export function SiteSectionTabs(props: {
 
     const containerRef = React.useRef<HTMLDivElement>(null);
     const currentTriggerRef = React.useRef<HTMLButtonElement | null>(null);
-    const [offset, setOffset] = React.useState<number | null>(null);
     const [value, setValue] = React.useState<string | undefined>();
 
-    const isMobile = useIsMobile(768);
-
-    React.useEffect(() => {
-        const trigger = currentTriggerRef.current;
-        const container = containerRef.current;
-        if (!value || !trigger || !container) {
-            return;
-        }
-
-        const triggerWidth = trigger.getBoundingClientRect().width - SCREEN_OFFSET;
-        const triggerLeft =
-            trigger.getBoundingClientRect().left -
-            (window.innerWidth - container.getBoundingClientRect().width) / 2;
-        setOffset(triggerLeft + triggerWidth / 2);
-    }, [value]);
+    const isMobile = useIsMobile(DESKTOP_BREAKPOINT);
+    const offset = useNavigationMenuViewportOffset({
+        value,
+        isMobile,
+        triggerRef: currentTriggerRef,
+        containerRef,
+    });
+    const viewportLeft =
+        !isMobile && offset !== null
+            ? `clamp(0px, calc(${offset - SCREEN_OFFSET}px - var(--radix-navigation-menu-viewport-width, 0px)/2), calc(100% - var(--radix-navigation-menu-viewport-width, 0px)))`
+            : '0px';
 
     return structure.length > 0 ? (
         <NavigationMenu.Root
@@ -65,6 +64,12 @@ export function SiteSectionTabs(props: {
                 className
             )}
             ref={containerRef}
+            style={
+                {
+                    '--site-section-column-width': COLUMN_WIDTH,
+                    '--site-section-column-gap': COLUMN_GAP,
+                } as React.CSSProperties
+            }
             value={value}
             onValueChange={setValue}
             skipDelayDuration={500}
@@ -122,11 +127,22 @@ export function SiteSectionTabs(props: {
                                                 icon={icon as IconName}
                                             />
                                         </NavigationMenu.Trigger>
-                                        <NavigationMenu.Content>
-                                            <SectionGroupTileList
-                                                items={structureItem.children}
-                                                currentSection={currentSection}
-                                            />
+                                        <NavigationMenu.Content
+                                            className={tcls([
+                                                'absolute top-0 left-0 w-full md:w-auto',
+                                                'data-[motion=from-start]:*:animate-[enterFromLeft_300ms_ease_both] data-[motion=to-end]:*:animate-[exitToRight_300ms_ease_both] data-[motion=to-start]:*:animate-[exitToLeft_300ms_ease_both] motion-safe:data-[motion=from-end]:*:animate-[enterFromRight_300ms_ease_both]',
+                                            ])}
+                                        >
+                                            <div
+                                                className={tcls(
+                                                    'max-h-[calc(100vh-8rem)] w-full overflow-y-auto overflow-x-hidden'
+                                                )}
+                                            >
+                                                <SectionGroupTileList
+                                                    items={structureItem.children}
+                                                    currentSection={currentSection}
+                                                />
+                                            </div>
                                         </NavigationMenu.Content>
                                     </>
                                 ) : (
@@ -153,23 +169,18 @@ export function SiteSectionTabs(props: {
 
             <div
                 className="absolute top-full left-0 z-20 flex w-full"
-                style={{
-                    padding: `0 ${SCREEN_OFFSET}px 0 ${SCREEN_OFFSET}px`,
-                }}
+                style={{ paddingInline: `${SCREEN_OFFSET}px` }}
             >
                 <NavigationMenu.Viewport
                     className={tcls(
-                        'relative origin-top overflow-auto circular-corners:rounded-3xl rounded-corners:rounded-xl border border-tint bg-tint-base shadow-lg ease-in-out',
-                        '-mt-0.5 w-full md:w-max',
+                        'relative origin-[center_top] overflow-hidden circular-corners:rounded-3xl rounded-corners:rounded-xl border border-tint bg-tint-base shadow-lg',
+                        '-mt-0.5 h-(--radix-navigation-menu-viewport-height) w-full max-w-full md:w-(--radix-navigation-menu-viewport-width)',
                         'max-h-[calc(100vh-8rem)] data-[state=closed]:animate-scale-out data-[state=open]:animate-scale-in',
-                        "[&:not([style*='--radix-navigation-menu-viewport-width'])]:hidden" // The viewport width is only calculated once it's triggered, and can take a while. We hide the viewport until it's ready.
+                        'ease has-[&[data-motion]]:transition-[left,width,height] has-[&[data-motion]]:duration-300'
                     )}
                     style={{
-                        translate:
-                            !isMobile && offset
-                                ? `clamp(0px, calc(${offset}px - var(--radix-navigation-menu-viewport-width, 0px)/2), calc(100vw - var(--radix-navigation-menu-viewport-width, 0px) - ${SCREEN_OFFSET * 3}px)) 0 0`
-                                : '0 0 0', // TranslateZ is needed to force a stacking context, fixing a rendering bug on Safari
-                        display: offset === null ? 'none' : undefined,
+                        left: viewportLeft,
+                        translate: '0 0 0', // TranslateZ is needed to force a stacking context, fixing a rendering bug on Safari
                     }}
                 />
             </div>
@@ -177,6 +188,41 @@ export function SiteSectionTabs(props: {
     ) : null;
 }
 
+function useNavigationMenuViewportOffset(args: {
+    value: string | undefined;
+    isMobile: boolean;
+    triggerRef: React.RefObject<HTMLButtonElement | null>;
+    containerRef: React.RefObject<HTMLDivElement | null>;
+}) {
+    const { value, isMobile, triggerRef, containerRef } = args;
+    const [offset, setOffset] = React.useState<number | null>(null);
+
+    React.useLayoutEffect(() => {
+        if (isMobile) {
+            setOffset(null);
+            return;
+        }
+
+        if (!value) {
+            return;
+        }
+
+        const trigger = triggerRef.current;
+        const container = containerRef.current;
+        if (!trigger || !container) {
+            return;
+        }
+
+        const containerLeft = container.getBoundingClientRect().left;
+        const triggerWidth = trigger.getBoundingClientRect().width;
+        const triggerLeft = trigger.getBoundingClientRect().left - containerLeft;
+
+        setOffset(triggerLeft + triggerWidth / 2);
+    }, [containerRef, isMobile, triggerRef, value]);
+
+    return offset;
+}
+
 /**
  * A tab representing a section or section group
  */
@@ -222,14 +268,16 @@ function SectionGroupTileList(props: {
 
     const hasSections = sections.length > 0;
     const hasGroups = groups.length > 0;
+    const isMasonryLayout = groups.length > GROUP_MASONRY_THRESHOLD;
+    const masonryColumnCount = Math.min(Math.ceil(groups.length / 2), MAX_MASONRY_COLUMNS);
 
     return (
-        <div className="flex flex-col md:flex-row">
+        <div className="flex w-full flex-col md:flex-row">
             {/* Non-grouped sections */}
             {hasSections && (
                 <ul
                     className={tcls(
-                        'flex min-w-48 shrink-0 grid-flow-row flex-col gap-x-2 gap-y-1 self-start p-3 md:grid',
+                        'flex w-full shrink-0 grid-flow-row flex-col gap-x-2 gap-y-0.5 self-stretch p-3 md:sticky md:top-0 md:grid md:w-max md:self-start',
                         hasGroups ? 'bg-tint-base' : ''
                     )}
                     style={{
@@ -248,25 +296,38 @@ function SectionGroupTileList(props: {
 
             {/* Grouped sections */}
             {hasGroups && (
-                <ul
+                <div
                     className={tcls(
-                        'grow gap-x-8 space-y-8 p-3',
-                        groups.length > GROUP_MASONRY_THRESHOLD
-                            ? 'w-screen md:columns-[15rem]'
-                            : 'flex flex-col justify-start md:flex-row md:items-start',
+                        'w-full md:w-max md:min-w-0 md:max-w-full',
                         hasSections
                             ? 'border-tint-subtle bg-tint-subtle max-md:border-t md:border-l'
                             : ''
                     )}
                 >
-                    {groups.map((group) => (
-                        <SectionGroupTile
-                            key={group.id}
-                            child={group}
-                            currentSection={currentSection}
-                        />
-                    ))}
-                </ul>
+                    <ul
+                        className={tcls(
+                            'p-3',
+                            isMasonryLayout
+                                ? 'w-full max-md:space-y-8 md:w-max md:max-w-full md:gap-x-[var(--site-section-column-gap)] md:[column-count:var(--masonry-columns)] md:[&>li]:mb-4'
+                                : 'flex w-full flex-col justify-start space-y-8 md:w-max md:flex-row md:items-start md:gap-[var(--site-section-column-gap)] md:space-y-0'
+                        )}
+                        style={
+                            isMasonryLayout
+                                ? ({
+                                      '--masonry-columns': String(masonryColumnCount),
+                                  } as React.CSSProperties)
+                                : undefined
+                        }
+                    >
+                        {groups.map((group) => (
+                            <SectionGroupTile
+                                key={group.id}
+                                child={group}
+                                currentSection={currentSection}
+                            />
+                        ))}
+                    </ul>
+                </div>
             )}
         </div>
     );
@@ -278,38 +339,40 @@ function SectionGroupTileList(props: {
 function SectionGroupTile(props: {
     child: ClientSiteSection | ClientSiteSectionGroup;
     currentSection: ClientSiteSection;
+    invertIcon?: boolean;
 }) {
-    const { child, currentSection } = props;
+    const { child, currentSection, invertIcon } = props;
 
     if (child.object === 'site-section') {
         const { url, icon, title, description } = child;
         const isActive = child.id === currentSection.id;
         return (
-            <li className="group/section-tile flex shrink-0 grow md:max-w-68">
+            <li className="group/section-tile flex w-full min-w-0 shrink-0 grow md:max-w-[var(--site-section-column-width)]">
                 <Link
                     href={url}
                     className={tcls(
-                        'grow circular-corners:rounded-2xl rounded-corners:rounded-lg px-3 py-2 transition-colors',
+                        'grow circular-corners:rounded-2xl rounded-corners:rounded-lg px-2.5 py-1.5 transition-colors',
                         isActive
                             ? 'bg-primary-active text-primary-strong'
                             : 'text-tint-strong hover:bg-tint-hover'
                     )}
                 >
-                    <div className="mb-auto flex grow items-center gap-2">
+                    <div className="mb-auto flex min-w-0 grow items-center gap-2">
                         {icon && (
                             <div
                                 className={tcls(
                                     '-ml-1 self-start circular-corners:rounded-2xl rounded-corners:rounded-lg p-2 transition-colors',
+                                    isActive || invertIcon ? 'bg-primary-base' : 'bg-tint',
                                     isActive
-                                        ? 'bg-primary-base text-primary-subtle'
-                                        : 'bg-tint text-tint-strong group-hover/section-tile:bg-tint-base'
+                                        ? 'text-primary-subtle'
+                                        : 'text-tint-strong group-hover/section-tile:bg-tint-base'
                                 )}
                             >
                                 <SectionIcon isActive={isActive} icon={icon as IconName} />
                             </div>
                         )}
-                        <div className="flex flex-col gap-1">
-                            {title}
+                        <div className="flex min-w-0 flex-col gap-0.5">
+                            <span className="block min-w-0 whitespace-normal">{title}</span>
                             {description && (
                                 <p className={isActive ? 'text-primary' : 'text-tint'}>
                                     {description}
@@ -326,15 +389,15 @@ function SectionGroupTile(props: {
     const { title, icon, children } = child;
 
     return (
-        <li className="flex shrink-0 break-inside-avoid flex-col gap-1">
-            <div className="mt-3 mb-1 flex gap-2.5 px-3 font-semibold text-tint-subtle text-xs uppercase tracking-wider">
+        <li className="flex w-full min-w-0 shrink-0 break-inside-avoid flex-col gap-1 md:w-auto">
+            <div className="mt-2 mb-1 flex min-w-0 gap-2 px-2.5 font-semibold text-tint-subtle text-xs">
                 {icon && (
                     <SectionIcon className="mt-0.5" isActive={false} icon={icon as IconName} />
                 )}
-                {title}
+                <span className="min-w-0 flex-1 whitespace-normal">{title}</span>
             </div>
             <ul
-                className="flex grid-flow-row flex-col gap-x-2 gap-y-1 md:grid"
+                className="flex w-full grid-flow-row flex-col gap-x-2 gap-y-0.5 md:grid"
                 style={{
                     gridTemplateColumns: `repeat(${Math.ceil(children.length / MAX_ITEMS_PER_COLUMN)}, minmax(0, auto))`,
                 }}
@@ -344,6 +407,7 @@ function SectionGroupTile(props: {
                         key={nestedChild.id}
                         child={nestedChild}
                         currentSection={currentSection}
+                        invertIcon={true}
                     />
                 ))}
             </ul>