# Feature Specification: Frontend Style Unification

**Feature Branch**: `[001-unify-frontend-style]`  
**Reference UX**: `[ux_reference.md]` (See specific folder)  
**Created**: 2026-02-23  
**Status**: Draft  
**Input**: User description: "Даю тебе полный кардбланш на приведение фронтэнда к единому стилю. Прочитай .ai/ROOT.md, используй всю методологию workflow speckit при разработке. Вперед"

## User Scenarios & Testing *(mandatory)*

### User Story 1 - Consistent Visual Foundation (Priority: P1)

As a product user, I want all major screens and shared UI blocks to look and behave consistently so that the interface feels coherent and predictable.

**Why this priority**: This is the core business value of the request. Without a shared visual baseline, every other UX improvement remains fragmented.

**Independent Test**: Can be fully tested by opening key routes (dashboards, tasks, reports, settings) and confirming that shared UI primitives (spacing, typography hierarchy, cards, buttons, states) are visually consistent and predictable.

**Acceptance Scenarios**:

1. **Given** a user opens two different primary routes, **When** they compare page structure and shared controls, **Then** they see the same spacing rhythm, typography hierarchy, and interaction patterns.
2. **Given** a user interacts with common controls (buttons, tabs, cards), **When** the controls are viewed across different pages, **Then** they have consistent style variants and state behavior.

---

### User Story 2 - Unified Navigation and Page Shells (Priority: P2)

As a user navigating between sections, I want navigation, headers, and content shells to follow one pattern so that I can orient quickly and reduce navigation errors.

**Why this priority**: Once visual foundation exists, navigation consistency delivers immediate usability gains and lowers cognitive load.

**Independent Test**: Can be tested independently by traversing main navigation paths and confirming shell consistency (title placement, breadcrumbs behavior, action region layout, content container behavior).

**Acceptance Scenarios**:

1. **Given** a user switches between at least three top-level pages, **When** each page loads, **Then** page shell structure (title, context, actions, content container) follows one standard pattern.
2. **Given** a user relies on breadcrumbs and navigation cues, **When** they move deeper and back in the hierarchy, **Then** navigation cues remain consistent and unambiguous.

---

### User Story 3 - Predictable Feedback and States (Priority: P3)

As a user performing actions, I want loading, empty, success, and error states to be consistent across modules so that I always understand system status and next steps.

**Why this priority**: Consistent state feedback improves trust and task completion, but can be delivered after foundational visual and navigation unification.

**Independent Test**: Can be tested by triggering common states (loading data, empty results, validation errors, successful actions) on selected modules and verifying consistent tone, placement, and recovery guidance.

**Acceptance Scenarios**:

1. **Given** a user opens a page with delayed data, **When** loading is shown, **Then** loading indicators follow one standard style and placement pattern.
2. **Given** a user encounters an empty or error state, **When** the state appears, **Then** the message format and recovery action style are consistent with other modules.

---

### Edge Cases

- What happens when legacy components cannot be visually aligned without breaking current behavior?  
  The system keeps behavior intact while applying the closest approved style fallback and records the component for deferred refinement.
- How does system handle mixed localized text lengths affecting unified layout?  
  Layout rules must preserve readability and alignment under longer labels and translated text.
- What happens when a page includes highly custom data widgets that do not match standard containers?  
  The page still applies shared shell and spacing rules while allowing controlled exceptions for specialized content blocks.
- How does system handle accessibility-related differences (focus ring, contrast expectations) during unification?  
  Accessibility-preserving variants take precedence over purely decorative alignment.

## Requirements *(mandatory)*

### Functional Requirements

- **FR-001**: System MUST define and apply a single frontend style baseline for typography hierarchy, spacing rhythm, color usage roles, and corner/radius behavior across primary user-facing pages.
- **FR-002**: System MUST standardize shared component presentation patterns for page headers, cards, buttons, form sections, and content containers.
- **FR-003**: Users MUST be able to navigate between core sections and observe consistent page shell structure, including title region, contextual navigation cues, and action placement.
- **FR-004**: System MUST provide consistent state presentation rules for loading, empty, success, and error states in all targeted modules.
- **FR-005**: System MUST preserve existing functional behavior while applying style unification; visual refactoring must not remove or alter core task flows.
- **FR-006**: System MUST define explicit exception handling rules for modules/components that cannot fully conform immediately, including fallback styling and documented follow-up actions.
- **FR-007**: System MUST align user-facing text tone and terminology in UI status messages to a unified voice and naming pattern.
- **FR-008**: System MUST ensure unified styling remains compatible with existing localization and accessibility expectations (focus visibility, readable contrast, scalable layout for longer labels).

### Key Entities *(include if feature involves data)*

- **Style Token Group**: A logical definition of visual decisions (e.g., typography roles, spacing steps, semantic color roles, shape rules) used to enforce consistent appearance.
- **UI Pattern Rule**: A reusable standard for structural or interaction patterns (e.g., page shell, action bar, card section, state message block).
- **State Presentation Pattern**: A canonical rendering and messaging rule for loading, empty, success, and error states.
- **Conformance Scope Item**: A mapped frontend area (route/component group) with current conformance status, expected target pattern, and exception note if needed.

## Success Criteria *(mandatory)*

### Measurable Outcomes

- **SC-001**: At least 90% of targeted primary frontend pages conform to the approved style baseline in a structured review checklist.
- **SC-002**: Users can identify page title, navigation cue, and primary action location on targeted pages in under 5 seconds during UX validation walkthroughs.
- **SC-003**: In cross-page UX review, at least 95% of sampled loading/empty/error/success states follow the same message and layout conventions.
- **SC-004**: At least 80% of internal reviewers rate the updated UI as “visually consistent” or better after unification.
- **SC-005**: No critical user flow regressions are introduced in the set of core routes covered by the style unification scope.

---

## Test Data Fixtures *(recommended for CRITICAL components)*

### Fixtures

```yaml
style_review_sample:
  description: "Representative result set for style conformance review"
  data:
    pages_checked:
      - dashboards
      - tasks
      - reports
      - settings
    conformance_summary:
      fully_conformant: 3
      partially_conformant: 1
      deferred_exceptions: 1

state_feedback_sample:
  description: "Representative UI state messages for consistency checks"
  data:
    loading_state:
      message: "Loading data…"
      action: null
    empty_state:
      message: "No items found"
      action: "Refresh or adjust filters"
    error_state:
      message: "Unable to load data"
      action: "Retry"
    success_state:
      message: "Changes saved"
      action: null
