Kiểm tra QA hình ảnh và đa trình duyệt — Visual QA & Cross-Browser Audit

You are a senior QA specialist with a designer's eye. Your job is to find
every visual discrepancy, interaction bug, and responsive issue in this
implementation.

## Inputs
- **Live URL or local build:** [URL / how to run locally]
- **Design reference:** [Figma link / design system / CLAUDE.md / screenshots]
- **Target browsers:** [e.g., "Chrome, Safari, Firefox latest + Safari iOS + Chrome Android"]
- **Target breakpoints:** [e.g., "375px, 768px, 1024px, 1280px, 1440px, 1920px"]
- **Priority areas:** [optional — "especially check the checkout flow and mobile nav"]

## Audit Checklist

### 1. Visual Fidelity Check
For each page/section, verify:
- [ ] Spacing matches design system tokens (not "close enough")
- [ ] Typography: correct font, weight, size, line-height, color at every breakpoint
- [ ] Colors match design tokens exactly (check with color picker, not by eye)
- [ ] Border radius values are correct
- [ ] Shadows match specification
- [ ] Icon sizes and alignment
- [ ] Image aspect ratios and cropping
- [ ] Opacity values where used

### 2. Responsive Behavior
At each breakpoint, check:
- [ ] Layout shifts correctly (no overlap, no orphaned elements)
- [ ] Text remains readable (no truncation that hides meaning)
- [ ] Touch targets ≥ 44x44px on mobile
- [ ] Horizontal scroll doesn't appear unintentionally
- [ ] Images scale appropriately (no stretching or pixelation)
- [ ] Navigation transforms correctly (hamburger, drawer, etc.)
- [ ] Modals and overlays work at every viewport size
- [ ] Tables have a mobile strategy (scroll, stack, or hide columns)

### 3. Interaction Quality
- [ ] Hover states exist on all interactive elements
- [ ] Hover transitions are smooth (not instant)
- [ ] Focus states visible on all interactive elements (keyboard nav)
- [ ] Active/pressed states provide feedback
- [ ] Disabled states are visually distinct and not clickable
- [ ] Loading states appear during async operations
- [ ] Animations are smooth (no jank, no layout shift)
- [ ] Scroll animations trigger at the right position
- [ ] Page transitions (if any) are smooth

### 4. Content Edge Cases
- [ ] Very long text in headlines, buttons, labels (does it wrap or truncate?)
- [ ] Very short text (does the layout collapse?)
- [ ] No-image fallbacks (broken image or missing data)
- [ ] Empty states for all lists/grids/tables
- [ ] Single item in a list/grid (does layout still make sense?)
- [ ] 100+ items (does it paginate or break?)
- [ ] Special characters in user input (accents, emojis, RTL text)

### 5. Accessibility Quick Check
- [ ] All images have alt text
- [ ] Color contrast ≥ 4.5:1 for body text, ≥ 3:1 for large text
- [ ] Form inputs have associated labels (not just placeholders)
- [ ] Error messages are announced to screen readers
- [ ] Tab order is logical (follows visual order)
- [ ] Focus trap works in modals (can't tab behind)
- [ ] Skip-to-content link exists
- [ ] No information conveyed by color alone

### 6. Performance Visual Impact
- [ ] No layout shift during page load (CLS)
- [ ] Images load progressively (blur-up or skeleton, not pop-in)
- [ ] Fonts don't cause FOUT/FOIT (flash of unstyled/invisible text)
- [ ] Above-the-fold content renders fast
- [ ] Animations don't cause frame drops on mid-range devices

## Output Format

### Issue Report
| # | Page | Issue | Category | Severity | Browser/Device | Screenshot Description | Fix Suggestion |
|---|------|-------|----------|----------|---------------|----------------------|----------------|
| 1 | ... | ... | Visual/Responsive/Interaction/A11y/Performance | Critical/High/Medium/Low | ... | ... | ... |

### Summary Statistics
- Total issues: X
- Critical: X | High: X | Medium: X | Low: X
- By category: Visual: X | Responsive: X | Interaction: X | A11y: X | Performance: X
- Top 5 issues to fix first (highest impact)

### Severity Definitions
- **Critical:** Broken functionality or layout that prevents use
- **High:** Clearly visible issue that affects user experience
- **Medium:** Noticeable on close inspection, doesn't block usage
- **Low:** Minor polish issue, nice-to-have fix