feat(theming): add OS-adaptive auto themes (sap_horizon_auto, sap_horizon_hc_auto)#13300
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feat(theming): add OS-adaptive auto themes (sap_horizon_auto, sap_horizon_hc_auto)#13300
Conversation
…themes
Add auto-switching themes that adapt to the user's OS light/dark preference
using CSS light-dark() for color values and space toggles for non-color values.
At build time, the light and dark theme CSS outputs are merged into a single
stylesheet. Color variables use the native CSS light-dark() function (Chrome 123+,
Firefox 120+, Safari 17.5+). Non-color variables use the space toggle pattern
with guaranteed-invalid custom properties, the same approach already used for
cozy/compact density switching.
The auto theme is self-contained: switching away from it removes the toggles.
No runtime code changes needed — it is purely CSS-driven.
Usage:
- URL: ?sap-ui-theme=sap_horizon_auto
- JS: setTheme("sap_horizon_auto")
- Config: <script data-ui5-config>{"theme":"sap_horizon_auto"}</script>
Collaborator
|
🧹 Preview deployment cleaned up: https://pr-13300--ui5-webcomponents.netlify.app |
…ptive themes Merge HCW (light) and HCB (dark) high contrast themes using the same light-dark() and space toggle mechanism as the existing auto themes, enabling automatic switching based on OS prefers-color-scheme.
pskelin
changed the title
Remove sap_fiori_3_auto and sap_fiori_3_hc_auto to reduce scope. Only sap_horizon_auto and sap_horizon_hc_auto are generated.
pskelin
changed the title
pskelin
approved these changes
Mar 19, 2026
Collaborator
|
🎉 This PR is included in version v2.21.0-rc.2 🎉 The release is available on v2.21.0-rc.2 Your semantic-release bot 📦🚀 |
Collaborator
|
🎉 This PR is included in version v2.21.0 🎉 The release is available on v2.21.0 Your semantic-release bot 📦🚀 |
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Summary
sap_horizon_autotheme that automatically switches between light and dark based on the user's OS preferencesap_horizon_hc_autotheme that automatically switches between high contrast white (HCW) and high contrast black (HCB)light-dark()for color values and space toggles for non-color values — purely CSS-driven, no runtime changesHow it works
At build time, the existing light and dark theme CSS outputs are merged into a single stylesheet:
light-dark(lightVal, darkVal)(native CSS function)--_ui5-light-scheme/--_ui5-dark-scheme(same guaranteed-invalid trick as cozy/compact density):rootoutput getscolor-scheme: light darkand a@media (prefers-color-scheme: dark)rule to flip the togglesThe same mechanism applies to high contrast themes — HCW maps to light mode, HCB maps to dark mode.
Usage
Theme pairs
sap_horizon_autosap_horizonsap_horizon_darksap_horizon_hc_autosap_horizon_hcwsap_horizon_hcbFiles changed
packages/tools/assets-meta.js— register new theme namespackages/tools/lib/css-processors/css-processor-themes.mjs— merge light+dark after processing, add toggle setup for theming packagepackages/tools/lib/css-processors/merge-light-dark.mjs— new: merge two CSS strings usinglight-dark()and space togglesparameters-bundle.cssfiles — enable theme directory discovery by the build systemTest plan
yarn generate && yarn startthen open?sap-ui-theme=sap_horizon_auto?sap-ui-theme=sap_horizon_hc_autoswitches between HCW/HCB based on OS color schemesap_horizon) removes the auto behavior