feat(sbb-stepper): introduce sbb-stepper component

src/elements/core/styles/a11y.scss

@@ -3,3 +3,13 @@
 .sbb-screen-reader-only {
   @include a11y.screen-reader-only;
 }
+
+.sbb-focus-outline:focus-visible {
+  @include a11y.focus-outline;
+}
+
+.sbb-focus-outline-dark:focus-visible {
+  @include a11y.focus-outline;
+
+  --sbb-focus-outline-color: var(--sbb-focus-outline-color-dark);
+}

src/elements/stepper.ts

@@ -0,0 +1,3 @@
+export * from './stepper/step.js';
+export * from './stepper/step-label.js';
+export * from './stepper/stepper.js';

src/elements/stepper/step-label.ts

@@ -0,0 +1 @@
+export * from './step-label/step-label.js';

src/elements/stepper/step-label/__snapshots__/step-label.spec.snap.js

@@ -0,0 +1,132 @@
+/* @web/test-runner snapshot v1 */
+export const snapshots = {};
+
+snapshots["sbb-step-label renders Dom"] = 
+`<sbb-step-label
+  data-action=""
+  data-button=""
+  dir="ltr"
+  id="sbb-step-label-0"
+  role="tab"
+  slot="step-label"
+  tabindex="-1"
+>
+  Label
+</sbb-step-label>
+`;
+/* end snapshot sbb-step-label renders Dom */
+
+snapshots["sbb-step-label renders ShadowDom"] = 
+`<div class="sbb-step-label">
+  <span class="sbb-step-label__prefix">
+    <slot name="icon">
+    </slot>
+  </span>
+  <span class="sbb-step-label__text">
+    <slot>
+    </slot>
+  </span>
+</div>
+`;
+/* end snapshot sbb-step-label renders ShadowDom */
+
+snapshots["sbb-step-label renders with icon Dom"] = 
+`<sbb-step-label
+  data-action=""
+  data-button=""
+  dir="ltr"
+  icon-name="tick-small"
+  id="sbb-step-label-2"
+  role="tab"
+  slot="step-label"
+  tabindex="-1"
+>
+  Label
+</sbb-step-label>
+`;
+/* end snapshot sbb-step-label renders with icon Dom */
+
+snapshots["sbb-step-label renders with icon ShadowDom"] = 
+`<div class="sbb-step-label">
+  <span class="sbb-step-label__prefix">
+    <slot name="icon">
+      <sbb-icon
+        aria-hidden="true"
+        data-namespace="default"
+        name="tick-small"
+        role="img"
+      >
+      </sbb-icon>
+    </slot>
+  </span>
+  <span class="sbb-step-label__text">
+    <slot>
+    </slot>
+  </span>
+</div>
+`;
+/* end snapshot sbb-step-label renders with icon ShadowDom */
+
+snapshots["sbb-step-label renders disabled Dom"] = 
+`<sbb-step-label
+  data-action=""
+  data-button=""
+  data-disabled=""
+  dir="ltr"
+  disabled=""
+  id="sbb-step-label-4"
+  role="tab"
+  slot="step-label"
+  tabindex="-1"
+>
+  Label
+</sbb-step-label>
+`;
+/* end snapshot sbb-step-label renders disabled Dom */
+
+snapshots["sbb-step-label renders disabled ShadowDom"] = 
+`<div class="sbb-step-label">
+  <span class="sbb-step-label__prefix">
+    <slot name="icon">
+    </slot>
+  </span>
+  <span class="sbb-step-label__text">
+    <slot>
+    </slot>
+  </span>
+</div>
+`;
+/* end snapshot sbb-step-label renders disabled ShadowDom */
+
+snapshots["sbb-step-label A11y tree Chrome"] = 
+`<p>
+  {
+  "role": "WebArea",
+  "name": "",
+  "children": [
+    {
+      "role": "tab",
+      "name": "Label"
+    }
+  ]
+}
+</p>
+`;
+/* end snapshot sbb-step-label A11y tree Chrome */
+
+snapshots["sbb-step-label A11y tree Firefox"] = 
+`<p>
+  {
+  "role": "document",
+  "name": "",
+  "children": [
+    {
+      "role": "tab",
+      "name": "Label"
+    }
+  ]
+}
+</p>
+`;
+/* end snapshot sbb-step-label A11y tree Firefox */
+

src/elements/stepper/step-label/readme.md

@@ -0,0 +1,54 @@
+Use the `sbb-step-label` with the `sbb-stepper` to display a step label.
+
+```html
+<sbb-step-label>Step label</sbb-step-label>
+```
+
+## Slots
+
+It has an implicit slot named `step-label`.
+
+## States
+
+The component can be displayed in `disabled` state using the self-named property.
+
+```html
+<sbb-step-label disabled>Step label</sbb-step-label>
+```
+
+## Style
+
+If it is used in an `sbb-stepper` and no `icon-name` is specified, it displays a counter in the label prefix to keep track of the step number.
+
+```html
+<!-- Displays a tick icon in the prefix circle -->
+<sbb-step-label icon-name="tick-small">Step label</sbb-step-label>
+
+<!-- Displays a number in the prefix circle -->
+<sbb-step-label>Step label</sbb-step-label>
+```
+
+## Accessibility
+
+The accessibility properties `aria-controls`, `aria-setsize`, `aria-posinset` are set automatically.
+
+<!-- Auto Generated Below -->
+
+## Properties
+
+| Name       | Attribute   | Privacy | Type                     | Default    | Description                                                                                                                      |
+| ---------- | ----------- | ------- | ------------------------ | ---------- | -------------------------------------------------------------------------------------------------------------------------------- |
+| `disabled` | `disabled`  | public  | `boolean`                | `false`    | Whether the component is disabled.                                                                                               |
+| `form`     | `form`      | public  | `string \| undefined`    |            | The <form> element to associate the button with.                                                                                 |
+| `iconName` | `icon-name` | public  | `string \| undefined`    |            | The icon name we want to use, choose from the small icon variants from the ui-icons category from here https://icons.app.sbb.ch. |
+| `name`     | `name`      | public  | `string`                 |            | The name of the button element.                                                                                                  |
+| `step`     | -           | public  | `SbbStepElement \| null` | `null`     | The step controlled by the label.                                                                                                |
+| `type`     | `type`      | public  | `SbbButtonType`          | `'button'` | The type attribute to use for the button.                                                                                        |
+| `value`    | `value`     | public  | `string`                 |            | The value of the button element.                                                                                                 |
+
+## Slots
+
+| Name   | Description                                      |
+| ------ | ------------------------------------------------ |
+|        | Use the unnamed slot to provide a label.         |
+| `icon` | Use this to display an icon in the label bubble. |

src/elements/stepper/step-label/step-label.scss

@@ -0,0 +1,153 @@
+@use '../../core/styles' as sbb;
+
+// Box-sizing rules contained in typography are not traversing Shadow DOM boundaries. We need to include box-sizing mixin in every component.
+@include sbb.box-sizing;
+
+:host {
+  --sbb-step-label-color: var(--sbb-color-iron);
+  --sbb-step-label-animation-duration: var(
+    --sbb-disable-animation-zero-time,
+    var(--sbb-animation-duration-2x)
+  );
+  --sbb-step-label-prefix-size: var(--sbb-size-element-xxs);
+  --sbb-step-label-prefix-border-style: solid;
+  --sbb-step-label-prefix-border-color: var(--sbb-color-cloud);
+  --sbb-step-label-prefix-background-color: var(--sbb-color-white);
+
+  position: relative;
+  min-width: 0;
+  max-width: fit-content;
+
+  &::before {
+    @include sbb.text-xxs--regular;
+    @include sbb.absolute-center-x-y;
+
+    cursor: var(--sbb-step-label-cursor);
+    color: var(--sbb-step-label-color);
+
+    // The `--sbb-font-size-text-l` is beign used here to align the bubble's inner text to
+    // the label text which includes the `sbb.text-l--bold` mixin.
+    inset-block-start: calc(
+      var(--sbb-font-size-text-l) * (var(--sbb-typo-line-height-body-text) / 2) +
+        (var(--sbb-border-width-1x) / 2)
+    );
+    inset-inline-start: calc(var(--sbb-step-label-prefix-size) / 2);
+    line-height: 1;
+    z-index: 1;
+    transform: translate(
+      -50%,
+      calc(-50% + var(--sbb-step-label-translate-y-content-hover, #{sbb.px-to-rem-build(0)}))
+    );
+    transition: transform var(--sbb-step-label-animation-duration) var(--sbb-animation-easing);
+  }
+
+  @include sbb.if-forced-colors {
+    --sbb-step-label-color: ButtonText;
+    --sbb-step-label-prefix-border-color: ButtonText;
+  }
+}
+
+:host([data-selected]) {
+  @include sbb.text-xxs--bold;
+
+  --sbb-step-label-color: var(--sbb-color-charcoal);
+
+  @include sbb.if-forced-colors {
+    --sbb-step-label-color: Highlight !important;
+  }
+}
+
+:host([disabled]) {
+  --sbb-step-label-color: var(--sbb-color-granite);
+  --sbb-step-label-prefix-border-style: dashed;
+
+  @include sbb.if-forced-colors {
+    --sbb-step-label-color: GrayText !important;
+  }
+}
+
+:host(:hover:not([disabled])) {
+  @include sbb.hover-mq($hover: true) {
+    --sbb-step-label-cursor: pointer;
+    --sbb-step-label-prefix-background-color: var(--sbb-color-milk);
+    --sbb-step-label-translate-y-content-hover: #{sbb.px-to-rem-build(-1)};
+    --sbb-step-label-prefix-size-grow-hover: calc(var(--sbb-border-width-2x) * -1);
+  }
+}
+
+// Hide focus outline when focus origin is mouse or touch. This is being used as a workaround in various components.
+:host(:focus-visible:not([data-focus-origin='mouse'], [data-focus-origin='touch'])) {
+  @include sbb.focus-outline;
+
+  border-radius: var(--sbb-border-radius-1x);
+}
+
+:host([data-orientation='vertical']) {
+  transition: margin var(--sbb-stepper-animation-duration) var(--sbb-animation-easing);
+}
+
+:host([data-orientation='vertical']:not(:first-of-type)) {
+  margin-block-start: var(--sbb-spacing-fixed-6x);
+}
+
+:host([data-selected][data-orientation='vertical']) {
+  margin-block-end: var(--sbb-spacing-fixed-8x);
+}
+
+.sbb-step-label {
+  @include sbb.text-l--bold;
+
+  cursor: var(--sbb-step-label-cursor);
+  position: relative;
+  display: flex;
+  gap: var(--sbb-spacing-fixed-4x);
+  color: var(--sbb-step-label-color);
+}
+
+.sbb-step-label__prefix {
+  position: relative;
+  display: flex;
+  flex-shrink: 0;
+  align-items: center;
+  justify-content: center;
+  width: var(--sbb-step-label-prefix-size);
+  height: var(--sbb-step-label-prefix-size);
+  inset-block-start: calc(
+    1em * (var(--sbb-typo-line-height-body-text) / 2) + (var(--sbb-border-width-1x) / 2) -
+      (var(--sbb-step-label-prefix-size) / 2)
+  );
+
+  &::before {
+    content: '';
+    position: absolute;
+    inset: calc(var(--sbb-step-label-prefix-size-grow-hover, #{sbb.px-to-rem-build(0)}));
+    border-radius: var(--sbb-border-radius-infinity);
+    border: var(--sbb-border-width-1x) var(--sbb-step-label-prefix-border-style)
+      var(--sbb-step-label-prefix-border-color);
+    background-color: var(--sbb-step-label-prefix-background-color);
+    transition: {
+      duration: var(--sbb-step-label-animation-duration);
+      timing-function: var(--sbb-animation-easing);
+      property: background-color, inset;
+    }
+  }
+}
+
+.sbb-step-label__text {
+  :host([data-orientation='horizontal']) & {
+    @include sbb.ellipsis;
+  }
+}
+
+::slotted(sbb-icon),
+sbb-icon {
+  z-index: 1;
+  background-color: var(--sbb-step-label-prefix-background-color);
+  border-radius: var(--sbb-border-radius-infinity);
+  transform: translateY(var(--sbb-step-label-translate-y-content-hover, #{sbb.px-to-rem-build(0)}));
+  transition: {
+    duration: var(--sbb-step-label-animation-duration);
+    timing-function: var(--sbb-animation-easing);
+    property: background-color, transform;
+  }
+}