frontend-slides

What this skill does

# Frontend Slides

Create zero-dependency, animation-rich HTML presentations that run entirely in the browser.

## Core Principles

1. **Zero Dependencies** — Single HTML files with inline CSS/JS. No npm, no build tools.
2. **Show, Don't Tell** — Generate visual previews, not abstract choices. People discover what they want by seeing it.
3. **Distinctive Design** — No generic "AI slop." Every presentation must feel custom-crafted.
4. **Progressive Disclosure** — Read lightweight style indexes first. For bold templates, use small preview cards for style previews and load the full `design.md` only after the user picks that template.
5. **Fixed 16:9 Stage (NON-NEGOTIABLE)** — Every deck uses a 1920×1080 slide canvas scaled as a whole to the viewport. Slides must stay 16:9 on every screen, including phones. Do not reflow slide content to fit the device.

## Design Aesthetics

You tend to converge toward generic, "on distribution" outputs. In frontend design, this creates what users call the "AI slop" aesthetic. Avoid this: make creative, distinctive frontends that surprise and delight.

Focus on:

- Typography: Choose fonts that are beautiful, unique, and interesting. Avoid generic fonts like Arial and Inter; opt instead for distinctive choices that elevate the frontend's aesthetics.
- Color & Theme: Commit to a cohesive aesthetic. Use CSS variables for consistency. Dominant colors with sharp accents outperform timid, evenly-distributed palettes. Draw from IDE themes and cultural aesthetics for inspiration.
- Motion: Use animations for effects and micro-interactions. Prioritize CSS-only solutions for HTML. Use Motion library for React when available. Focus on high-impact moments: one well-orchestrated page load with staggered reveals (animation-delay) creates more delight than scattered micro-interactions.
- Backgrounds: Create atmosphere and depth rather than defaulting to solid colors. Layer CSS gradients, use geometric patterns, or add contextual effects that match the overall aesthetic.

Avoid generic AI-generated aesthetics:

- Overused font families (Inter, Roboto, Arial, system fonts)
- Cliched color schemes (particularly purple gradients on white backgrounds)
- Predictable layouts and component patterns
- Cookie-cutter design that lacks context-specific character

Interpret creatively and make unexpected choices that feel genuinely designed for the context. Vary between light and dark themes, different fonts, different aesthetics. You still tend to converge on common choices (Space Grotesk, for example) across generations. Avoid this: it is critical that you think outside the box!

## Fixed Stage Rules

These invariants apply to EVERY slide in EVERY presentation:

- Every deck has a viewport wrapper that fills the browser window.
- Every slide is authored inside a fixed 1920×1080 stage.
- The stage scales uniformly to fit the viewport. It may letterbox/pillarbox; it must not re-layout content.
- Do not use responsive breakpoints to rearrange slide content for phones.
- Use fixed internal slide measurements at the 1920×1080 design size.
- Slide visibility must be controlled by `.active` / `.visible` using `visibility`, `opacity`, and `pointer-events` from `viewport-base.css`. Do not use `display: none` / `display: block` for slide switching; later layout classes such as `.slide-content { display: flex; }` can override them and make every slide visible at once.
- Use `clamp()` only for non-slide UI outside the stage, or for small fallback previews where a full stage is impractical.
- Include `prefers-reduced-motion` support
- Never negate CSS functions directly (`-clamp()`, `-min()`, `-max()` are silently ignored) — use `calc(-1 * clamp(...))` instead

**When generating, read `viewport-base.css` and include its full contents in every presentation.**

### Content Density Modes

Ask the user whether this is primarily a reading deck or a speaking deck, then design around that answer:

| Density mode | Best for | Design behavior |
| ------------- | -------- | --------------- |
| **Low density / speaker-led** | Public talks, keynote-style sharing, live explanation | One idea per slide, large type, strong visual hierarchy, generous negative space, 1-3 bullets max, more slides if needed |
| **High density / reading-first** | Reports, handouts, async review, detailed internal docs | More self-contained slides, structured grids/tables/annotations, 4-8 bullets or 4-6 cards when readable, tighter but still intentional spacing |

Baseline limits still apply: no scrolling, no overflow, no overlapping panels, and no text below comfortable reading size. If content exceeds the selected density mode, split it into more slides instead of shrinking until it becomes cramped.

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## Phase 0: Detect Mode

Determine what the user wants:

- **Mode A: New Presentation** — Create from scratch. Go to Phase 1.
- **Mode B: PPT Conversion** — Convert a .pptx file. Go to Phase 4.
- **Mode C: Enhancement** — Improve an existing HTML presentation. Read it, understand it, enhance. **Follow Mode C modification rules below.**

### Mode C: Modification Rules

When enhancing existing presentations, fixed-stage fitting is the biggest risk:

1. **Before adding content:** Count existing elements, check against density limits
2. **Adding images:** Fit them inside the 1920×1080 slide canvas. If slide already has max content, split into two slides
3. **Adding text:** Max 4-6 bullets per slide. Exceeds limits? Split into continuation slides
4. **After ANY modification, verify:** the slide stage remains 16:9, no text overflows its card, no panels overlap, and screenshots look correct at 1280×720 plus one phone viewport
5. **Proactively reorganize:** If modifications will cause overflow, automatically split content and inform the user. Don't wait to be asked

**When adding images to existing slides:** Move image to a new slide or reduce other content first. Never add images without checking if existing content already fills the 1920×1080 slide stage.

---

## Phase 1: Content Discovery (New Presentations)

**Ask ALL questions together** so the user fills everything out at once. If the current environment provides a native structured-question UI, use it; otherwise ask in one concise message with clearly numbered choices:

**Question 1 — Purpose** (header: "Purpose"):
What is this presentation for? Options: Pitch deck / Teaching-Tutorial / Conference talk / Internal presentation

**Question 2 — Length** (header: "Length"):
Approximately how many slides? Options: Short 5-10 / Medium 10-20 / Long 20+

**Question 3 — Content** (header: "Content"):
Do you have content ready? Options: All content ready / Rough notes / Topic only

**Question 4 — Density** (header: "Density"):
How dense should the deck feel? Options:

- "Low density / speaker-led" — Big ideas, fewer words, more visual breathing room
- "High density / reading-first" — More self-contained detail for async reading

**Do not ask about inline editing during Phase 1.** Users should not have to choose editing behavior before seeing a draft. Inline editing is a post-draft affordance: include it by default unless the user explicitly asks for a locked/export-only file.

Remember the user's density choice. It affects slide count, typography scale, amount of text per slide, layout density, and whether to favor cinematic presenter slides or self-contained reading slides.

If user has content, ask them to share it.

### Step 1.2: Image Evaluation (if images provided)

If user selected "No images" → skip to Phase 2.

If user provides an image folder:

1. **Scan** — List all image files (.png, .jpg, .svg, .webp, etc.)
2. **Inspect each image** — Use the agent's available image-understanding capability. If image reading is unavailable, use filenames/metadata and ask the user to clarify only when needed
3. **Evaluate** — For each: what it shows, USABLE or NOT USABLE (with reason), what concept it represents, dominant colors
4. **Co-design the outlin