[Simple Analytics] Accessibility #208

Is your enhancement related to a problem? Please describe.

Ensure full accessibility compliance including keyboard navigation, screen reader support, and proper color contrast.

Technical Context:

• Requires WCAG 2.1 AA + WordPress core a11y guidelines
• Chart tooltips must be keyboard and screen reader accessible

Implementation Breakdown

• Charts: aria-label on canvas elements; hidden <table> alternatives for screen readers; keyboard-navigable tooltips
• Use sufficient color contrast (4.5:1 text, 3:1 large text); don't rely on color alone (add labels/patterns)
• KPI cards: semantic HTML (<section>, <h2>), aria-label per card
• Filters: proper <label> elements; keyboard-navigable datepicker; aria-live region for content updates on filter change
• Page heading hierarchy: h1 > h2 > h3 logical structure
• All interactive elements focusable with visible focus indicators
• All error messages wrapped in __() / esc_html__() for translation

Acceptance Criteria

• All charts have screen reader accessible data tables
• Keyboard navigation works for all interactive elements (filters, tooltips, links)
• Color contrast meets WCAG standards
• aria-live regions announce content updates

Designs

No response

Describe alternatives you've considered

No response

Code of Conduct

• I agree to follow this project's Code of Conduct