Allow unprefixed Dialog max-width classes to override the default viewport cap at desktop breakpoints.

Sidebar: mobile rewrite, smooth collapse transitions, and new props

New features:

• mobileBreakpoint prop on Provider — configurable viewport width for mobile detection
• contentClassName prop on Sidebar root — pass-through class for the inner content container
• Controlled mobile state — open prop now controls the mobile sidebar too, not just desktop

Fixes:

• Replaced Base UI Dialog mobile sidebar with a plain <nav> + backdrop for simpler, more predictable transitions
• Collapsible sections now animate closed smoothly when the sidebar collapses instead of snapping shut
• Removed hidden class from Sidebar.MenuSub so sub-menus participate in collapse animations
• Removed inertValue React-version helper — SidebarSlidingView now sets inert imperatively for React 18 compatibility
• Restored inert on closed SidebarCollapsibleContent while removing its data-open attribute

Styling:

• bg-kumo-tint → bg-(--sidebar-active-bg) CSS variable for active/hover/focus backgrounds
• Icon opacity 0.5 → 0.4; chevron gains hover opacity transition
• Header gains shrink-0 and animated padding on collapse
• Content scroll area gains animated gap transition and tabIndex={-1} on viewport
• Sliding views container gains max-w-(--sidebar-width) to prevent overflow
• Mobile sidebar uses --sidebar-animation-duration CSS variable for slide transition

Add React 18 and React 19 compatibility checks for Kumo tests.

Fix Chart (and SankeyChart) rendering in dark mode. The chart canvas now stays transparent so the surrounding bg-kumo-* surface shows through symmetrically in both modes, and ECharts' built-in "dark" theme is applied when isDarkMode is true so the tooltip card, axes, splitLines, and legend text are themed correctly.

fix(sidebar): add text truncation with ellipsis to Sidebar.MenuButton content

Previously, Sidebar.MenuButton used overflow-hidden which clipped long text without showing an ellipsis. Now uses truncate to match Sidebar.MenuSubButton's behavior.

Fix segmented Tabs scroll fade, scroll-into-view, and ring styling:

• Rewrite CSS scroll-fade masking to use @property-animated custom properties, fixing proportional fade rendering across browsers.
• Scroll the selected tab into view on click so it stays visible in overflowing tab lists.
• Move ring ring-kumo-hairline/70 from the inner list to the root container so the segmented variant ring wraps the entire component correctly.

Fix Flow connector rendering in Firefox by emitting valid SVG path data without array commas and setting visible overflow on the SVG element attribute.

Restore React 18-compatible Sidebar inert attribute handling while keeping the full React compatibility CI suite.

Fix Combobox and Autocomplete rendering in React 18 by using the explicit context provider API.

Update Banner to use borderless tinted styling by default and add a secondary variant.

Re-export useFilter from Combobox and Autocomplete namespaces. Use it to write custom filter props that preserve Base UI's default case- and accent-insensitive matching via Intl.Collator.

Sidebar: comprehensive modernization

Breaking changes:

• Removed Sidebar.Input — build custom search triggers inline
• Removed Sidebar.MenuAction — unused in practice
• Removed Sidebar.GroupContent and group-level collapsible props (collapsible, defaultOpen, open, onOpenChange) from Sidebar.Group — use Sidebar.Collapsible at the item level instead
• Replaced Base UI Collapsible dependency with custom CSS grid-rows implementation
• SidebarState type is now "expanded" | "collapsed" | "peeking" (was "expanded" | "collapsed")

New features:

• contained prop on Provider — absolute positioning for embedded/demo sidebars
• peekable prop on Provider — hover/focus collapsed sidebar to temporarily expand
• animationDuration prop on Provider — configurable animation timing
• Sidebar.SlidingViews + Sidebar.SlidingView — animated horizontal transitions between navigation surfaces
• Animated SidebarPanelIcon replacing Phosphor SidebarSimpleIcon
• Enhanced Sidebar.Trigger with aria-expanded and dynamic aria-label
• Keyboard-accessible resize handle (arrow keys, Home, End)
• Custom Sidebar.Collapsible with keyboard auto-expand on focus

Token/styling fixes:

• border-kumo-hairline → border-kumo-line throughout
• Hardcoded duration-250 → --sidebar-animation-duration CSS custom property
• bg-kumo-base → bg-(--sidebar-bg) for theme overridability
• Focus styles: ring-2/ring-kumo-brand → outline-none/text-kumo-strong/bg-kumo-tint
• Icon opacity-50, updated spacing (header h-58px, footer h-12, menu gap-y-px)
• isolate on sidebar root with low z-index (z-1, z-2) instead of z-20/z-50
• Mobile sidebar now has correct data-state/data-side/data-variant/data-collapsible attributes

TimeseriesChart: React tooltip with Base UI positioning

Replaces ECharts' HTML-string tooltip with a React component positioned by Base UI's Tooltip primitive:

• Tooltip rendered as a React component with correct theme tokens — no more inline styles or getComputedStyle hacks
• Positioning handled by Base UI Tooltip (Floating UI), with automatic collision avoidance and viewport flipping
• New tooltipFollowCursor prop: "both" (default, free-following) or "x" (axis-locked, Recharts-style)
• New tooltipMode prop: "all" (default) or "single" (nearest series to cursor)
• New tooltipMaxItems prop: caps rows in "all" mode with +N more footer (default 10)
• Date formatted with Intl.DateTimeFormat (locale-aware) instead of ISO string
• Values sorted descending; fallback formatter avoids scientific notation

Banner: replace dark: Tailwind variants with new kumo-banner-info and kumo-banner-warning semantic tokens so dark-mode opacity is baked into the design system. No visual change.

fix(styles): show pointer cursor on clickable Kumo elements by default

Adds a global cursor: pointer rule scoped to elements rendered by Kumo components, identified by the new data-kumo-component and data-kumo-part attributes. Interactive component roots and parts now opt into the rule by setting these attributes, which gives the library a stable scoping primitive that doesn't couple to Tailwind class names.

Components updated to set data-kumo-component / data-kumo-part: Button, LinkButton, Link, Checkbox, Radio, Switch, Select (trigger, option), DropdownMenu (item, link-item, checkbox-item, radio-item, submenu-trigger), Combobox (trigger, item, clear, chip-remove), Autocomplete (item), Dialog (trigger, close), Popover (trigger), Tabs (tab), Collapsible (trigger, default-trigger), Breadcrumbs (link), TableOfContents (item, group-link), Sidebar (menu-button, menu-sub-button, trigger, rail), MenuBar (option), Toast (close), SensitiveInput (toggle-visibility, copy, masked-container).

fix(sidebar): collapsed state styling, transitions, and sliding views

Add flex items-center to ComboboxBase.Icon in TriggerInput for consistency with TriggerValue and Select

Fix Select placeholder not showing when renderValue is provided and the value is empty.

Update semantic color tokens to better represent status icons and indicators:

• Adjust status token values in the theme generator and refresh generated theme output
• Update toast and badge status background treatments
• Update docs to reflect new tint token usage

Adjust toast visual styling for improved readability and emphasis: increase background tint intensity for success/warning/info variants, refine description text contrast, and update close-button icon contrast.

Fixed vertical alignment of checkbox and radio indicators with multi-line labels.

When label text wrapped to multiple lines, the indicators were vertically centered against the entire text block. They now align to the top, sitting next to the first line of text.

echarts is now an optional peer dependency. If you don't use Chart components (Chart, TimeseriesChart, SankeyChart), it will no longer be installed automatically. If you do use them, run npm install echarts (as documented).

Added Badge dot styling as a new variant for indicators that need a subtle visual cue. Updated badge docs and demo examples to reflect the new badge variant and dot-style behavior.

Update Base UI to 1.5.0.

Fix InputGroup focus ring thickness and color: container mode uses 1.5px ring (wraps entire group including buttons), hybrid container zone and individual mode use 1px ring (thin to avoid colliding with adjacent buttons), and all modes use ring-kumo-focus/50 (50% opacity) to match the standalone Input component.

Fix error state red border on Combobox, Select, Autocomplete, and SensitiveInput to match Input behavior

Add inline label layout and fix auto-assigned node colors in tooltips

Fix Tooltip popup overflowing viewport when content is wider than available space. The popup now constrains its width to var(--available-width), a CSS variable provided by Base UI's Positioner that reflects the space between the trigger and the viewport edge.

Fix language alias normalization in ShikiProvider

• Add normalizeLanguage() function that maps common language aliases (js, ts, sh, yml, py, md, gql) to their canonical SupportedLanguage names
• Normalize language aliases in ShikiProvider when preloading grammars, so passing ['js', 'ts'] works the same as ['javascript', 'typescript']
• Normalize language aliases in highlight() hook at runtime, so code fences using js or ts highlight correctly without warnings
• Export normalizeLanguage from @cloudflare/kumo/code for consumers who need to normalize aliases themselves
• Intentionally omit mdx alias since MDX has a distinct grammar that would lose JSX highlighting if mapped to markdown

fix(banner): remove variant selection background for legibility

Selected text inside Banner now uses the browser default selection color instead of a same-hue variant-tinted background. The previous selection:bg-kumo-{info,warning,danger} utilities produced low contrast between the selection background and the variant text color (most notably in light mode for the error and alert variants), making selected text hard to read.

Add left and right props to SankeyChart for controlling series layout padding

Fix tooltip popup exit transitions by animating the Tailwind scale property alongside opacity.

Add passwordManagerIgnore to Input for suppressing password manager overlays on non-credential fields.

Add scroll fade to segmented tabs. When tabs overflow, gradient masks appear on the edges based on scroll position via scroll-driven animations (Chrome 115+, degrades gracefully). Scrollbar is hidden; the fade is the scroll affordance.

Add size="sm" variant to Tabs component (h-6.5 / 26px, matching Input sm)

Forward toastManager prop on <Toasty> so code outside the React tree (timers, query-cache listeners, module-load callbacks) can dispatch toasts via a manager created by createKumoToastManager(). Also surface createKumoToastManager on the top-level package export (previously only available via the deep @cloudflare/kumo/components/toast path).

Add transparent background to SankeyChart component

Expose optionUpdateBehavior prop on TimeseriesChart to control how ECharts applies option updates

Add hideLabel prop to Field so components can skip the native <label> while keeping description/error wiring. Use it in Select with Base UI's Select.Label to fix hover/focus coupling between the label text and trigger.

fix(input): render error and description props without requiring a label

fix(radio): prevent radio button distortion with long labels by adding shrink-0 to the default appearance radio indicator

Fix overflowing segmented Tabs drag-to-scroll interactions so mouse and touch drags reliably scroll while normal tab clicks still activate tabs.

Create Sankey Chart component

Fix CommandPalette List bottom ring being clipped by Footer background. Add scroll padding to prevent items from clipping behind rounded corners.

Deprecate to prop on Link in favor of href. The to prop is a routing-framework concept that doesn't belong on a presentational component. Use href for all link destinations and configure a LinkProvider wrapper to bridge to your router. to continues to work but emits a dev-mode deprecation warning.

Allow LayerCard.Primary and LayerCard.Secondary to accept all standard HTML div attributes, including data-testid for testing.

Set cursor-default on Tooltip triggers so disclosure buttons don't appear clickable. Overridable via className.

Export Combobox.Trigger, Combobox.Value, and Combobox.Icon — the raw Base UI primitives for building custom combobox triggers. Use these when you need full control over the trigger's visual treatment (e.g. a sidebar account switcher that renders as a plain button instead of an input-like control).