This article is about an upcoming feature. It is not available on production releases yet.
Web Themes are a way to customise the layout and styling of end-user visible web pages hosted on the Service. These include pages such as:
OpenID authorisation (sign in),
New user registration,
Password reset,
and most others, excluding the “/ui” management site.
For some pages the whole layout as well as style is configurable. For others only the style is configurable.
Breaking changes
Web themes replaces the “Branding Styles” (Branding: Styles) by providing similar functionality. “Branding styles” allows injection of CSS rules into the page. Web themes allows this as well. Using both at the same time is not recommended. Most existing “Branding Styles” rules can be used as-is in a web theme.
Some built-in customer specific CSS rules are no longer available. They must be implemented as Web Themes to keep the existing style.
Web theme structure and usage
A web theme can contain several alternative layouts for various pages, a default style, and several additional alternative styles.
Layouts
Some layouts contain components whose content will be other layouts. For example, the login view has a “base” layout which contains a dynamically changing internal section which may contain the “enter username and password” layout or other layouts.
Some pages can have alternative layouts. Which layout is picked depends on how the page was opened. The OpenID authorisation pages (and user registration opened from it) may have a standard “display” query parameters, with values such as “page”, “touch”, “popup” or “wap” as described in the OpenID Connect standard. The “page” layout is the default if display is not specified.
Styles
A default style can be included, as well as several additional styles which can be combined with the default style.
The default style is provided by adding a CSS stylesheet named “default”. If no default style is included, a built-in default style is used. If a default style is written into the theme, the built-in default style is not used.
Additional stylesheets can be provided with other names. The additional styles are injected into the page after the default style. Only one of the additional styles is used at a time. This enables using the same theme in different situations with minor stylistic changes. When a theme is selected, either the default style or the default plus an additional style are selected at the same time.
Management of web themes
Web themes are managed in the management interface. Editors need some of the following permissions:
View web themes
Create web themes
Modify web themes
Remove web themes
Web themes are not namespace-specific, so having access to them means having access to all of them. On some service installations this means great trust is placed on the editors.
Management view
Management view is opened from the main menu by selecting “Web themes”.
The management view enables users to list, create, copy, edit and remove web themes.
Web theme editor
Creating or editing an existing theme opens the Theme editor. You can name the editor and configure layouts and styles within.
The editor contains a tree selector where you can select or add layouts and and stylesheets. The layouts and styles are named, and you pick the name when the layout or style is first created.
The theme is saved by clicking the Save button. The changes are viewable immediately in pages where web themes are used.
Activating web themes
One theme can be picked as the default theme. This is done in the System Preferences / Branding section. One theme and one style combination can be selected there.
In OpenID Client settings, any theme and style combination can be selected per client. By default the same theme as is selected in Branding configuration is used.
Layout structure
The layouts are defined as HTML documents. The content must be compatible with Vaadin 8 Designer. Additional documentation is found at the Vaadin 8 documentation site.
Stylesheet structure
Stylesheets are normal CSS documents. They are injected into the <head> section of the web page.