Editorial Card Screenshot

Overview

Turn source text into a compact, high-contrast HTML information card that follows the user's editorial prompt, then render a screenshot in one of the supported aspect ratios.

Always preserve three output stages unless the user explicitly asks to skip one:

1. Write one sentence judging the information density as high, medium, or low.
2. Output the complete HTML with embedded CSS.
3. Self-check that body text remains readable on mobile.

Workflow

1. Analyze Content Density

Choose layout strategy from the content itself:

• Use "big-character" composition when content is sparse and a single phrase, number, or hook can carry the page.
• Use a two-column or three-column editorial grid when content is dense and needs stronger hierarchy.
• Use oversized numbers, heavy rules, tinted blocks, and pull-quote scale to avoid dead space.
• Do not force dense content into evenly weighted tiles. Build primary blocks, secondary blocks, and lighter supporting blocks.
• Match structure to content type:
  • Ranking / recommendation content: allow asymmetric hero + structured list.
  • Tutorial / analysis / interpretation content: group into overview, core judgment, interpretation, boundary, and conclusion.

Before compressing content, first change the layout skeleton.

• Ratio changes should primarily change reading path, hierarchy, and module arrangement.
• Do not treat ratio changes as a reason to delete content by default.
• Only compress, group, or summarize when the current ratio cannot hold the content clearly after layout has already been restructured.

2. Apply the Stored Editorial Rules

Use these defaults unless the user overrides them:

• Import Google Fonts:

  \x3Clink href="https://fonts.googleapis.com/css2?family=Noto+Serif+SC:wght@700;900&family=Noto+Sans+SC:wght@400;500;700&family=Oswald:wght@500;700&family=Inter:wght@400;600;700&display=swap" rel="stylesheet">
  

• Keep body text at 18px to 20px on a 900px-wide composition.
• Keep meta/tag text at 13px minimum.
• Use compact spacing: container padding 40px to 50px, component gaps 30px to 40px, line-height 1.5 to 1.6.
• Add visual weight with 4px to 6px accent rules, subtle gray planes, and 4% noise overlays.
• Favor #f5f3ed or similar warm-paper backgrounds unless the user supplies another palette.
• Preserve breathing room. Do not shrink outer margins so much that the card loses composure.
• For title zones, prefer larger line-height and clearer separation from subtitle / summary blocks.
• In dense right-side modules, reduce font weight slightly so the page stays clear without feeling heavy.
• Use stronger internal structure inside blocks: subheads, bullets, numbered lines, compare rows, or secondary labels.
• Avoid equal-weight boxes when the card is dense. At least one module should feel visually heavier than the others.

3. Choose the Right Layout Skeleton

Pick ratio-specific structure before writing final copy.

4:3

• Best for full analytical spread or ranked lists.
• Prefer: hero + summary band + dense two-column list + stronger footer.
• Use one main judgment block before the list so the page does not become a flat wall of 10 equal items.

3:4

• Keep the same information ambition, but change the reading path.
• Prefer: title band + insight row + mixed large/small body modules.
• Use mixed scales: one heavy primary block, one or two medium blocks, and smaller support blocks.
• Do not let the whole portrait card collapse into a long single column.

1:1

• Best for ability map, grouped comparison, or balanced editorial overview.
• Prefer: strong hero + one heavier quadrant + three supporting quadrants + dense footer strip.
• Square layouts should feel centered and modular, not evenly tiled.

Wide covers (3:1, 5:2, 2.35:1)

• Reduce paragraph length aggressively.
• Use fewer but larger blocks, stronger headlines, and short support lines.

4. Build HTML for Rendering

When HTML will be screenshotted, design the page as a fixed-size canvas instead of a responsive webpage:

• Match the exact pixel dimensions of the selected ratio preset from references/ratios.md.
• Treat the card as a design board with explicit width and height, not as a fluid 100vw / 100vh layout.
• Remove browser-default margins with html, body { margin: 0; }.
• Make the card itself fill the screenshot viewport exactly.
• Avoid interactions, sticky headers, or long scrolling sections.
• Use fixed pixel wrappers, for example:

  .frame {
    width: 2000px;
    height: 1500px;
  }
  
  .card {
    width: 100%;
    height: 100%;
    padding: 48px;
    background: #f5f3ed;
  }
  

Do not rely on 100vw, 100vh, or responsive container widths as the primary design size for screenshot output.

If the user asks only for HTML, still make the layout screenshot-ready.

Use these structural heuristics when composing the card:

• Fill the proportion intentionally. Rebalance layout according to width / height instead of scaling one static template.
• In 4:3 landscape, asymmetric left-right layouts often work best for dense analytical content.
• In 3:4 portrait, use portrait-friendly mixed grids rather than a single narrow column.
• Keep title, subtitle, summary, and modules separated by explicit rows or bands so they do not collide.
• If using numbered modules, keep numbers visually weak enough that they never collide with titles.
• If a section becomes visually monotonous, introduce contrast through hierarchy changes rather than decorative clutter.
• Let big modules carry richer copy than small modules. Do not give every block the same amount of text.

5. Capture the Screenshot

Use the bundled shell script when the user wants a PNG output:

./scripts/capture_card.sh input.html output.png 3:4

Supported ratios and render sizes live in references/ratios.md.

The rendering helper requires a local Chrome or Chromium binary. It first respects CHROME_BIN when set, then falls back to common binary names and a macOS Chrome app path.

Before running the script:

• Save the generated HTML to a local file.
• Ensure the page is self-contained except for fonts.
• If you keep the default font imports, rendering will request Google Fonts over the network.
• Ensure the HTML uses a fixed-size design canvas that matches the chosen ratio preset.
• Ensure the viewport composition already matches the requested ratio.

6. Ratio Policy

Accept only these ratio presets:

• 3:4
• 4:3
• 1:1
• 16:9
• 9:16
• 2.35:1
• 3:1
• 5:2

If the user gives a ratio outside this set, ask them to map it to the nearest supported preset rather than inventing a new one.

Output Contract

When responding to a card-generation request:

• Start with exactly one sentence describing information density.
• Then output complete HTML in one code block.
• If the user also requested an image, state the ratio used and the screenshot command after the HTML.
• Keep prose short; the HTML is the deliverable.

Resources

references/ratios.md

Open this when you need the exact preset names or capture dimensions.

references/editorial-card-prompt.md

Use this as the canonical prompt spec when the user wants the latest validated editorial-card behavior.

scripts/capture_card.sh

Run this to capture a PNG from a local HTML file using a supported ratio preset. It requires a local Chrome or Chromium binary or an explicit CHROME_BIN override.

assets/card-template.html

Use this as a starting shell when you want a minimal ratio-ready HTML canvas before filling in real content.

Failure Checks

Before finalizing HTML or PNG, explicitly reject the result if any of these happen:

• The title overlaps, visually collides with, or blocks summary/body content.
• The title becomes a narrow vertical strip when more horizontal width is available.
• Dense cards are split into too many equal-weight boxes.
• Large blocks contain too little copy and read like empty containers.
• The canvas shows large areas of dead space that could be filled by stronger hierarchy, richer block content, or a heavier main module.
• The PNG feels meaningfully emptier than the HTML layout intent.