Sheet

Present an authored native dialog from a viewport edge. Custom element

<ui-sheet modal>
  <button class="ui-button" data-ui-part="trigger" type="button" command="show-modal" commandfor="settings-sheet">Open sheet</button>
  <dialog id="settings-sheet" aria-labelledby="settings-sheet-title" aria-describedby="settings-sheet-description">
    <header>
      <h2 id="settings-sheet-title">Settings</h2>
      <button class="ui-button" data-ui-variant="ghost" data-ui-size="sm" data-ui-part="close" type="button" aria-label="Close sheet" command="close" commandfor="settings-sheet">
        <svg aria-hidden="true" focusable="false" viewBox="0 0 16 16">
      <path d="m4.5 4.5 7 7m0-7-7 7" fill="none" stroke="currentColor" stroke-linecap="round" stroke-width="1"/>
    </svg>
      </button>
      <p id="settings-sheet-description">Configure this preview.</p>
    </header>
    <section>
      <p>Changes apply immediately.</p>
    </section>
    <footer>
      <button class="ui-button" data-ui-variant="secondary" data-ui-part="close" type="button" command="close" commandfor="settings-sheet" value="cancel">Cancel</button>
      <button class="ui-button" data-ui-part="close" type="button" command="close" commandfor="settings-sheet" value="done">Done</button>
    </footer>
  </dialog>
</ui-sheet>

Install

import '@timelessui/components/css/tokens.css'
import '@timelessui/components/css/button.css'
import '@timelessui/components/css/sheet.css'
import '@timelessui/components/css/dialog.css'
import '@timelessui/components/define/ui-sheet'

Anatomy

Parts are authored in your own markup and identified by the selector below, so your CSS can target the same anatomy without loading Timeless styles. Required parts must be present for the component to work. Private data-ui-internal-* hooks are written by the runtime and must never be authored.

Part	Required	Selector	Purpose
`trigger`	Yes	`[data-ui-part~='trigger']`	Native button that opens the sheet. On a `modal` sheet, add `command="show-modal"` and `commandfor` naming the panel id to open it from markup, before any script runs. A non-modal sheet has no declarative equivalent: the platform has no built-in command for `dialog.show()`, so its trigger stays on the click listener.
`panel`	Yes	`dialog`	The native `<dialog>` element. Give it an explicit `id` when a trigger or close button invokes it, since an invoker can only name an id the author wrote.
`close`	No	`[data-ui-part~='close']`	Optional explicit close button. Add `command="close"` and `commandfor` to close it from markup, on modal and non-modal sheets alike; the platform then also copies the button `value` into `returnValue`.

Attributes

Every value below is implemented by the stylesheets this component ships. Boolean attributes are presence-based: author the attribute with no value, or omit it.

Attribute	Values	Default	Description
`modal`	presence	absent	Present to open the sheet as a modal, trapping focus and blocking the page behind it. Omit for a non-modal sheet the user can interact around.
`open`	presence	absent	Present to render the sheet open on load.
`position`	`top` · `right` · `bottom` · `left`	`right`	Which viewport edge the sheet slides in from.

Element API

Attributes above are the authoring surface. These are the DOM properties and events the registered element adds once it upgrades.

`<ui-sheet>`

Property	Type	Notes
`modal`	`boolean`	Reflects the `modal` attribute, documented above.
`open`	`boolean`	Reflects the `open` attribute, documented above.
`position`	`'top' \| 'right' \| 'bottom' \| 'left'`	Reflects the `position` attribute, documented above.

Event	Detail	Description
`ui-open`	`CustomEvent<SheetEventDetail>`	Dispatched after the sheet opens.
`ui-close`	`CustomEvent<SheetEventDetail>`	Dispatched after the sheet closes.
`ui-dismiss`	`CustomEvent<SheetEventDetail>`	Dispatched when the sheet closes through Escape or a backdrop click rather than an explicit control.

Styling

Root identity: ui-sheet. Required stylesheets: tokens.css, button.css, sheet.css, dialog.css.

This component adds no custom properties of its own. Restyle it through the design tokens or your own CSS.

Design tokens this component reads (30)

These are global Atmosphere tokens. Change them once at the theme level rather than per component.

--ui-accent · --ui-bg-accent · --ui-bg-accent-active · --ui-bg-accent-hover · --ui-bg-control · --ui-bg-control-active · --ui-bg-control-hover · --ui-bg-control-muted · --ui-bg-danger · --ui-bg-danger-active · --ui-bg-danger-hover · --ui-bg-surface · --ui-bg-surface-subtle · --ui-duration-fast · --ui-ease-standard · --ui-fg · --ui-fg-muted · --ui-focus · --ui-line · --ui-radius-control · --ui-radius-lg · --ui-shadow-control-accent · --ui-shadow-control-active · --ui-shadow-control-danger · --ui-shadow-floating · --ui-shadow-outline-control · --ui-space-2 · --ui-space-3 · --ui-space-4 · --ui-space-5

Accessibility

Keep the native elements, roles, and relationships shown in the example. Timeless adds only the state and keyboard coordination the platform does not already provide, and it never supplies your accessible names — those depend on your content.

Follows the Modal Dialog pattern from the ARIA Authoring Practices Guide.

Key	Action
`Escape`	Close the sheet. Handled by the native `<dialog>` element.

A modal sheet traps focus through showModal(); without modal the page stays interactive and focus is not trapped. Timeless restores focus to the trigger either way.

Before JavaScript runs

The markup above is complete and usable on its own: native controls submit, labels associate, and authored ARIA is already correct. Registration adds state synchronisation, focus management, and keyboard coordination on top of it.

More examples

Open Sheet in StoryLite for variants, controls, and manual testing.