Overview
dsh-client-ui-theme
Source-level overviewTheme plugin: ThemeRuntime over the --dsw-* token base stylesheets (static scale + alias semantic layers). The service owns the live theme preference (light/dark/system), resolves system through prefers-color-scheme, and publishes immutable ThemeSnapshots on the theme/change event; it never touches the DOM — ui-layout's presenter applies the resolved snapshot (html { color-scheme }, body[data-ds-dark-theme], and inline alias tokens). A loopback browser provides the service immediately with system, then loads ui-theme.preference in the background and writes each built-in selection through the Host settings API, whose local provider stores it in $DSH_HOME/settings.yaml by default; pushed settings changes and reconnects refetch it, rapid selections are serialized in gesture order with namespace revisions, and a rejected latest write reloads the durable value. A remote browser cannot access the privileged settings API, so its selection remains process-local. Third-party registered theme ids remain an in-process extension and do not cross the built-in settings schema; removing one never overwrites the last durable built-in preference. The Host-backed preferences decision owns the persistence boundary.Collapse technical overview
light/dark/system), resolves system through prefers-color-scheme, and publishes immutable ThemeSnapshots on the theme/change event; it never touches the DOM — ui-layout's presenter applies the resolved snapshot (html { color-scheme }, body[data-ds-dark-theme], and inline alias tokens). A loopback browser provides the service immediately with system, then loads ui-theme.preference in the background and writes each built-in selection through the Host settings API, whose local provider stores it in $DSH_HOME/settings.yaml by default; pushed settings changes and reconnects refetch it, rapid selections are serialized in gesture order with namespace revisions, and a rejected latest write reloads the durable value. A remote browser cannot access the privileged settings API, so its selection remains process-local. Third-party registered theme ids remain an in-process extension and do not cross the built-in settings schema; removing one never overwrites the last durable built-in preference. The Host-backed preferences decision owns the persistence boundary.This is an atomic module already shipped with Harness, not a standalone profile layer.
Capabilities
What it contributes
README / EN
Package documentation
@deepseek-ai/dsh-client-ui-theme
English | 中文
Theme plugin: ThemeRuntime over the --dsw-* token base stylesheets (static scale + alias semantic layers). The service owns the live theme preference (light/dark/system), resolves system through prefers-color-scheme, and publishes immutable ThemeSnapshots on the theme/change event; it never touches the DOM — ui-layout's presenter applies the resolved snapshot (html { color-scheme }, body[data-ds-dark-theme], and inline alias tokens). A loopback browser provides the service immediately with system, then loads ui-theme.preference in the background and writes each built-in selection through the Host settings API, whose local provider stores it in $DSH_HOME/settings.yaml by default; pushed settings changes and reconnects refetch it, rapid selections are serialized in gesture order with namespace revisions, and a rejected latest write reloads the durable value. A remote browser cannot access the privileged settings API, so its selection remains process-local. Third-party registered theme ids remain an in-process extension and do not cross the built-in settings schema; removing one never overwrites the last durable built-in preference. The Host-backed preferences decision owns the persistence boundary.
When the host composition includes an HTTP server, the host half injects a synchronous bootstrap immediately after the opening <body> tag. Each index response embeds the registered Host setting for ui-theme.preference, or system when no settings provider is present; the browser resolves system from the OS scheme, then sets color-scheme and body[data-ds-dark-theme] before the shell loading page renders. Compositions without an HTTP server remain unaffected, and ThemeRuntime and ui-layout remain authoritative for client state and subsequent DOM updates after the plugin tree activates.
src/styles/ holds five sheets, all imported by the web shell's base.css: base.css, design-platform.css, scrollbar.css, gradient-shadow-text.css, and shiki.css. scrollbar.css is the sole consumer of the --dsw-alias-scrollbar-* tokens and must follow design-platform.css, which declares them.
Scrollbar rebinding contract: scrollbar.css binds --dsh-scrollbar-thumb and --dsh-scrollbar-thumb-hover on body to the l1 (base-surface) tokens, and both rendering paths read that pair. An elevated surface (menu, popover, dialog) sets --dsh-scrollbar-thumb: var(--dsw-alias-scrollbar-bg-l2) and --dsh-scrollbar-thumb-hover: var(--dsw-alias-scrollbar-hover-l2) on its own container; one rebind retints whichever path the engine took. The pair's other legal target is transparent, which draws no thumb at all — ui-sidebar rebinds its column that way while the pointer is elsewhere. A rebind to the l1 pair is not a rebind; it restates the base-surface default. --dsh-scrollbar-width mirrors the WebKit bar's layout width for surfaces that align themselves beside a space-consuming bar — ui-conversation reads it for the overlay composer seat's right offset — and the scrollbar-styles spec pairs it with the mirrored rule and the consumer.
The two paths are mutually exclusive by construction. scrollbar-width/scrollbar-color sit inside @supports not selector(::-webkit-scrollbar) because a non-auto value of either makes Chromium and Safari discard every ::-webkit-scrollbar* rule for that element, ::-webkit-scrollbar-thumb:hover included — declaring both unconditionally leaves --dsh-scrollbar-thumb-hover with no rendering anywhere. Firefox therefore takes the standard properties and WebKit-based engines take the pseudo-elements, so the hover token only ever renders through the pseudo-element path. Reasoning and the measured computed values: the scrollbar Agent Note.
Model Experience
None, as the theme service manages a browser preference; nothing here reaches a model request.
KV Cache effect
None; this package neither assembles nor sends a provider request.
Known Limitations and Deferred Work
- Third-party themes are an extension point, not a product — registering one means overriding same-named alias variables; no validation exists that an override set is complete.
- The token sheets are the sole color authority — values absent from cssdesign (for example the design's #4176E6 tab blue) are deliberately not appended; the nearest semantic token wins. Design-owner-approved additions are the exception and enter as a static step plus a semantic alias in the same change (
--dsw-static-blue-900/--dsw-alias-label-primary-bluish).
LIMITATIONS
Known limitations
- **Third-party themes are an extension point, not a product** — registering one means overriding same-named alias variables; no validation exists that an override set is complete. - **The token sheets are the sole color authority** — values absent from cssdesign (for example the design's #4176E6 tab blue) are deliberately not appended; the nearest semantic token wins. Design-owner-approved additions are the exception and enter as a static step plus a semantic alias in the same change (`--dsw-static-blue-900` / `--dsw-alias-label-primary-bluish`).