Deprecated: This skill is superseded by goose-graphics. See skills/composites/goose-graphics/ (install with npx goose-skills install goose-graphics). The slides format is one of seven formats in the newer skill and supports 36 style presets plus image sourcing and PNG export. This skill is retained for one release cycle before removal.

Frontend Slides Skill

Create zero-dependency, animation-rich HTML presentations that run entirely in the browser. This skill helps non-designers discover their preferred aesthetic through visual exploration ("show, don't tell"), then generates production-quality slide decks.

Core Philosophy

1. Zero Dependencies — Single HTML files with inline CSS/JS. No npm, no build tools.
2. Show, Don't Tell — People don't know what they want until they see it. Generate visual previews, not abstract choices.
3. Distinctive Design — Avoid generic "AI slop" aesthetics. Every presentation should feel custom-crafted.
4. Production Quality — Code should be well-commented, accessible, and performant.
5. Viewport Fitting (CRITICAL) — Every slide MUST fit exactly within the viewport. No scrolling within slides, ever. This is non-negotiable.

CRITICAL: Viewport Fitting Requirements

This section is mandatory for ALL presentations. Every slide must be fully visible without scrolling on any screen size.

The Golden Rule

Each slide = exactly one viewport height (100vh/100dvh)
Content overflows? → Split into multiple slides or reduce content
Never scroll within a slide.

Content Density Limits

To guarantee viewport fitting, enforce these limits per slide:

If content exceeds these limits → Split into multiple slides

Required CSS Architecture

Every presentation MUST include this base CSS for viewport fitting:

/* ===========================================
   VIEWPORT FITTING: MANDATORY BASE STYLES
   These styles MUST be included in every presentation.
   They ensure slides fit exactly in the viewport.
   =========================================== */

/* 1. Lock html/body to viewport */
html, body {
    height: 100%;
    overflow-x: hidden;
}

html {
    scroll-snap-type: y mandatory;
    scroll-behavior: smooth;
}

/* 2. Each slide = exact viewport height */
.slide {
    width: 100vw;
    height: 100vh;
    height: 100dvh; /* Dynamic viewport height for mobile browsers */
    overflow: hidden; /* CRITICAL: Prevent ANY overflow */
    scroll-snap-align: start;
    display: flex;
    flex-direction: column;
    position: relative;
}

/* 3. Content container with flex for centering */
.slide-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    max-height: 100%;
    overflow: hidden; /* Double-protection against overflow */
    padding: var(--slide-padding);
}

/* 4. ALL typography uses clamp() for responsive scaling */
:root {
    /* Titles scale from mobile to desktop */
    --title-size: clamp(1.5rem, 5vw, 4rem);
    --h2-size: clamp(1.25rem, 3.5vw, 2.5rem);
    --h3-size: clamp(1rem, 2.5vw, 1.75rem);

    /* Body text */
    --body-size: clamp(0.75rem, 1.5vw, 1.125rem);
    --small-size: clamp(0.65rem, 1vw, 0.875rem);

    /* Spacing scales with viewport */
    --slide-padding: clamp(1rem, 4vw, 4rem);
    --content-gap: clamp(0.5rem, 2vw, 2rem);
    --element-gap: clamp(0.25rem, 1vw, 1rem);
}

/* 5. Cards/containers use viewport-relative max sizes */
.card, .container, .content-box {
    max-width: min(90vw, 1000px);
    max-height: min(80vh, 700px);
}

/* 6. Lists auto-scale with viewport */
.feature-list, .bullet-list {
    gap: clamp(0.4rem, 1vh, 1rem);
}

.feature-list li, .bullet-list li {
    font-size: var(--body-size);
    line-height: 1.4;
}

/* 7. Grids adapt to available space */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 250px), 1fr));
    gap: clamp(0.5rem, 1.5vw, 1rem);
}

/* 8. Images constrained to viewport */
img, .image-container {
    max-width: 100%;
    max-height: min(50vh, 400px);
    object-fit: contain;
}

/* ===========================================
   RESPONSIVE BREAKPOINTS
   Aggressive scaling for smaller viewports
   =========================================== */

/* Short viewports (< 700px height) */
@media (max-height: 700px) {
    :root {
        --slide-padding: clamp(0.75rem, 3vw, 2rem);
        --content-gap: clamp(0.4rem, 1.5vw, 1rem);
        --title-size: clamp(1.25rem, 4.5vw, 2.5rem);
        --h2-size: clamp(1rem, 3vw, 1.75rem);
    }
}

/* Very short viewports (< 600px height) */
@media (max-height: 600px) {
    :root {
        --slide-padding: clamp(0.5rem, 2.5vw, 1.5rem);
        --content-gap: clamp(0.3rem, 1vw, 0.75rem);
        --title-size: clamp(1.1rem, 4vw, 2rem);
        --body-size: clamp(0.7rem, 1.2vw, 0.95rem);
    }

    /* Hide non-essential elements */
    .nav-dots, .keyboard-hint, .decorative {
        display: none;
    }
}

/* Extremely short (landscape phones, < 500px height) */
@media (max-height: 500px) {
    :root {
        --slide-padding: clamp(0.4rem, 2vw, 1rem);
        --title-size: clamp(1rem, 3.5vw, 1.5rem);
        --h2-size: clamp(0.9rem, 2.5vw, 1.25rem);
        --body-size: clamp(0.65rem, 1vw, 0.85rem);
    }
}

/* Narrow viewports (< 600px width) */
@media (max-width: 600px) {
    :root {
        --title-size: clamp(1.25rem, 7vw, 2.5rem);
    }

    /* Stack grids vertically */
    .grid {
        grid-template-columns: 1fr;
    }
}

/* ===========================================
   REDUCED MOTION
   Respect user preferences
   =========================================== */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        transition-duration: 0.2s !important;
    }

    html {
        scroll-behavior: auto;
    }
}

Overflow Prevention Checklist

Before generating any presentation, mentally verify:

1. ✅ Every .slide has height: 100vh; height: 100dvh; overflow: hidden;
2. ✅ All font sizes use clamp(min, preferred, max)
3. ✅ All spacing uses clamp() or viewport units
4. ✅ Content containers have max-height constraints
5. ✅ Images have max-height: min(50vh, 400px) or similar
6. ✅ Grids use auto-fit with minmax() for responsive columns
7. ✅ Breakpoints exist for heights: 700px, 600px, 500px
8. ✅ No fixed pixel heights on content elements
9. ✅ Content per slide respects density limits

When Content Doesn't Fit

If you find yourself with too much content:

DO:

• Split into multiple slides
• Reduce bullet points (max 5-6 per slide)
• Shorten text (aim for 1-2 lines per bullet)
• Use smaller code snippets
• Create a "continued" slide

DON'T:

• Reduce font size below readable limits
• Remove padding/spacing entirely
• Allow any scrolling
• Cram content to fit

Testing Viewport Fit

After generating, recommend the user test at these sizes:

• Desktop: 1920×1080, 1440×900, 1280×720
• Tablet: 1024×768, 768×1024 (portrait)
• Mobile: 375×667, 414×896
• Landscape phone: 667×375, 896×414

Phase 0: Detect Mode

First, determine what the user wants:

Mode A: New Presentation

• User wants to create slides from scratch
• Proceed to Phase 1 (Content Discovery)

Mode B: PPT Conversion

• User has a PowerPoint file (.ppt, .pptx) to convert
• Proceed to Phase 4 (PPT Extraction)

Mode C: Existing Presentation Enhancement

• User has an HTML presentation and wants to improve it
• Read the existing file, understand the structure, then enhance