feat: optimize docs pages and add 4 new doc articles (en + zh)

- Rewrote DocsListPage and DocDetailPage with landing.css aesthetic
  (icon cards, skeleton loader, prose styles, CTA box)
- Added docs-specific CSS to landing.css
- Created image-to-latex, copy-to-word, ocr-accuracy, pdf-extraction
  articles in both English and Chinese
- Updated DocsSeoSection guide cards to link to real doc slugs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

content/docs/en/image-to-latex.md

@@ -0,0 +1,80 @@
+---
+title: Image to LaTeX
+description: How to convert any formula image into clean LaTeX code with TexPixel
+slug: image-to-latex
+date: 2026-03-25
+tags: [LaTeX, tutorial]
+order: 2
+---
+
+# Image to LaTeX
+
+TexPixel's core feature is converting formula images — from photos, scans, or screenshots — directly into LaTeX code you can paste anywhere.
+
+## How It Works
+
+1. **Upload your image** — Drag and drop a JPG or PNG into the upload zone, or click to browse. You can also paste from your clipboard.
+2. **AI processes it** — Our model detects the formula region, runs OCR, and generates structured LaTeX in under a second.
+3. **Copy the result** — Click the copy button next to the LaTeX output. Paste directly into Overleaf, VS Code, Word, or any LaTeX editor.
+
+## Input Requirements
+
+| Requirement | Details |
+|---|---|
+| File formats | JPG, PNG |
+| Max file size | 10 MB |
+| Recommended DPI | 150 DPI or higher |
+| Background | White or light backgrounds work best |
+
+## What Gets Recognized
+
+TexPixel handles a wide range of mathematical content:
+
+- **Algebra** — equations, inequalities, polynomials
+- **Calculus** — derivatives, integrals, limits
+- **Matrices** — 2×2 up to large arrays
+- **Greek letters** — α, β, γ, Σ, Π, and more
+- **Subscripts and superscripts** — `x_i^2`, `a_{n+1}`
+- **Fractions** — `\frac{a}{b}`, nested fractions
+- **Square roots and radicals** — `\sqrt{x}`, `\sqrt[n]{x}`
+
+## Example
+
+Uploading an image of the quadratic formula gives you:
+
+```latex
+x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}
+```
+
+An image of an integral:
+
+```latex
+\int_0^\infty e^{-x^2}\, dx = \frac{\sqrt{\pi}}{2}
+```
+
+## Tips for Best Results
+
+- **Use clear images** — avoid blur, shadows, or low contrast
+- **Crop tightly** — the less background, the better the focus
+- **Dark ink on white paper** — ideal for handwritten formulas
+- **Avoid rotated images** — keep the formula horizontal
+- **One formula per image** — for complex multi-part work, crop each formula separately
+
+## Limitations
+
+- Extremely faint or pencil-written formulas may have lower accuracy
+- Hand-drawn arrows or annotation marks outside the formula may be ignored
+- Very large matrices (10×10+) may have reduced accuracy
+
+## Copy Options
+
+After recognition, you can copy output in multiple formats:
+
+- **LaTeX** — raw LaTeX string
+- **MathML** — for web embedding
+- **Markdown** — `$...$` inline or `$$...$$` block
+- **Plain text** — Unicode approximation
+
+---
+
+Ready to try it? [Upload a formula image now →](/app)