Frontend Slides

Create beautiful, single-file HTML slide presentations. Each slide fills exactly one viewport — no scrolling within slides, no build tools, no frameworks. Inspired by zarazhangrui/frontend-slides.

Output: One .html file containing all CSS, JS, and slide content inline.

Font strategy: Every theme specifies a Google Fonts / Fontshare web font AND a system font fallback stack. Web fonts enhance — they are not required. Presentations must look good offline.

Reference files contain complete code templates. Load them on-demand — only read what you need for the current task.

Core Principles

1. One slide = one viewport. 100dvh, overflow: hidden, scroll-snap-align: start. Content that overflows → split into more slides.
2. All sizes use clamp(). No fixed px/rem for typography or spacing. Everything scales with the viewport.
3. Content density limits are hard rules. See the table below — never exceed them.
4. Single-file output. Fonts via CDN <link>, everything else inline. No external CSS/JS files.
5. Respect prefers-reduced-motion. All animations must have a reduced-motion fallback.

Viewport Fitting (Single Source of Truth)

This section is THE authority on viewport rules. Reference files do not repeat these — they assume this CSS is always present.

Required Base CSS

*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-snap-type: y mandatory;
  scroll-behavior: smooth;
  height: 100%;
}

body {
  font-family: var(--font-body);
  background: var(--bg-primary);
  color: var(--text-primary);
  overflow-x: hidden;
  height: 100%;
}

.slide {
  width: 100vw;
  height: 100vh;
  height: 100dvh;
  overflow: hidden;
  scroll-snap-align: start;
  display: flex;
  flex-direction: column;
  position: relative;
}

.slide-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  max-height: 100%;
  overflow: hidden;
  padding: var(--slide-padding);
}

Required CSS Variables

:root {
  /* Typography — MUST use clamp() */
  --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-size: clamp(0.75rem, 1.5vw, 1.125rem);
  --small-size: clamp(0.65rem, 1vw, 0.875rem);

  /* Spacing — MUST use clamp() */
  --slide-padding: clamp(1rem, 4vw, 4rem);
  --content-gap: clamp(0.5rem, 2vw, 2rem);
  --element-gap: clamp(0.25rem, 1vw, 1rem);

  /* Animation */
  --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);
  --duration-normal: 0.6s;
}

Responsive Breakpoints

/* 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 (< 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);
  }
  .nav-dots,
  .keyboard-hint,
  .decorative {
    display: none;
  }
}

/* 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);
  }
  .grid {
    grid-template-columns: 1fr;
  }
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.2s !important;
  }
  html {
    scroll-behavior: auto;
  }
}

Content Density Limits

Hard maximums per slide type. If content exceeds → split into multiple slides.

Slide Types

Seven standard types. See references/slide-components.md for complete HTML/CSS templates.

Theme Collection

8 curated themes across 3 categories. Each theme includes CSS variables, font pairings with system fallbacks, layout guidance, and signature element CSS.

Dark Themes → references/themes-dark.md

Light Themes → references/themes-light.md

Specialty Themes → references/themes-specialty.md

Font Fallback Strategy

Every theme has two font stacks — web (CDN) and system (offline).

When web fonts fail to load, the presentation must still look intentional — system fallbacks are chosen to preserve the theme's character.

Creation Workflow

1. User provides: topic, audience, optional theme preference
2. Choose theme: match audience/mood to theme vibe (see table above)
3. Load references:
   • Always: references/slide-template.md (HTML skeleton)
   • Always: the relevant references/themes-*.md (for chosen theme)
   • As needed: references/slide-components.md (for specific slide types)
   • As needed: references/animation-recipes.md (for advanced effects)
4. Plan slides: outline each slide with type + key content (respect density limits)
5. Generate: single HTML file using the skeleton, theme CSS, and component patterns
6. Verify: every slide fits viewport, no overflow, animations have reduced-motion fallback

CSS Gotchas

Negating CSS Functions

/* WRONG — silently ignored, no console error: */
right: -clamp(28px, 3.5vw, 44px);
margin-left: -min(10vw, 100px);

/* CORRECT — wrap in calc(): */
right: calc(-1 * clamp(28px, 3.5vw, 44px));
margin-left: calc(-1 * min(10vw, 100px));

Browsers silently discard declarations with - before clamp(), min(), max().

Image Constraints

.slide-image {
  max-width: 100%;
  max-height: min(50vh, 400px);
  object-fit: contain;
  border-radius: 8px;
}

.slide-image.screenshot {
  border: 1px solid rgba(255, 255, 255, 0.1);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

Grid Auto-Fit

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 250px), 1fr));
  gap: clamp(0.5rem, 1.5vw, 1rem);
}

Effect-to-Feeling Guide

DO NOT USE

• position: fixed for slides (breaks scroll-snap)
• Fixed px / rem for typography or spacing (use clamp())
• vh without dvh fallback (mobile address bar issues)
• overflow: auto/scroll on .slide (breaks one-slide-per-viewport rule)
• Google Fonts @import in CSS (use <link> in <head> for performance)
• More than 6 feature cards per grid slide
• Code blocks longer than 10 lines per slide

References