2151 skip to content component

[GCHQ-Developer-741]

NOTE: Do not merge until guidance is ready.

Summary of the changes

• Added the new ic-skip-link component to the web-components package (final confirmation from design still needed).
• Added stories to both web-components and react packages, including prop playgrounds.
• Added new style token to global styles relating to the new component.
• Added unit/cypress tests.

Related issue

#2151

Checklist

General

• Changes to docs package checked and committed.
• All acceptance criteria reviewed and met.

Testing

• Relevant unit tests and visual regression tests added.
• Visual testing against Figma component specification completed.
• Playground stories in React Storybook up to date, with any prop changes and additions addressed.
• Compare performance of modified components against develop using Performance addon in React Storybook.

Accessibility

• Accessibility Insights FastPass performed.
• A11y unit test added and yields no issues.
• A11y plug-in on Storybook yields no issues.
• Manual screen reader testing performed using NVDA and VoiceOver.
• Manual keyboard testing for keyboard controls and logical focus order.
• Correct roles used and ARIA attributes used correctly where required.
• Logical heading structure is maintained, and the HTML elements used for headings can be changed to fit within the wider page structure.

Resize/zoom behaviour

• Page can be zoomed to 400% with no loss of content.
• Screen magnifier used with no issues.
• Text resized to 200% with no loss of content.
• Text spacing increased as per the WCAG 1.4.12 success criterion with no loss of content.

System modes

• Browser setting 'prefers reduced motion' tested. No animations or motion visible whilst this setting is on.
• Windows High Contrast mode tested with no loss of content.
• System light and dark mode tested with no loss of content.
• Browser support tested (Chrome, Safari, Firefox and Edge).

Testing content extremes

• Min/max content examples tested with no loss of content or overflow.
• All prop combinations work without issue.
• Tested for FOUC (Flash of Unstyled Content) in both SSR (Server-Side Rendering) and SSG (Static Site Generation) settings.
• Controlled and uncontrolled input components tested.
• Props/slots can be updated after initial render.

[github-actions]

View your branch deployment here: https://mi6.github.io/ic-ui-kit/branches/2151-skip-to-content-component/web-components
View your React branch deployment here: https://mi6.github.io/ic-ui-kit/branches/2151-skip-to-content-component/react

[GCHQ-Developer-847]

Looks so good, noticed a few things but they are quite small :)

[github-actions]

Cypress visual tests failed.
View the image diff here: https://github.com/mi6/ic-ui-kit/tree/gh-pages/branches/2151-skip-to-content-component/cypress-image-diff-screenshots/diff
View the html report here: https://mi6.github.io/ic-ui-kit/branches/2151-skip-to-content-component/cypress-image-diff-html-report/cypress-image-diff-html-report.html

[GCHQ-Developer-847]

I'm still getting an issue with the full-width variant. It appears correctly if you keep the window at the same size, but once you make it bigger or smaller, the skip link no longer matches the window width i.e. it either gets cut off or is not wide enough

Everything else looks good to me now though :)

The merge-base changed after approval.