Understand Before You Build
- HTML
- CSS
- inset
- scroll-snap-type
- margin-inline
- Content-visibility
- Scroll-Driven Animations
- Isolation
- @Container
- @layer
- :not()
- :is()
- :Where()
- :has()
- :target
- backdrop-filter
- :root
- Color-scheme
- Animations
- Selectors
- Object-fit
- Logical Pseudo-Classes
- :scope
- Properties
- Performance
- Aspect-ratio
- State Pseudo-Classes
- Positioning
- Resize
- Structural Pseudo-Classes
- Responsive Design
- Units
- Root & Scope Selectors
- Scrolling
- At-Rules
- Target & URL Selectors
- Spacing
- Functions
- Attribute Selectors
- Layouts
- Basic Selectors
- Filters & Effects
- Colors & Typography
- Flexbox
- Combinator Selectors
- Grid
- Form & UI State Selectors
- AI CSS Generator
- Sass
- CSS Frameworks
- React UI
- Figma
Performance
Web Performance is the process of improving website speed, responsiveness, and loading efficiency.
A high-performance website loads faster and provides a smoother user experience.
Performance optimization is important for:
- Better user experience
- Faster page loading
- Improved SEO rankings
- Lower bounce rate
- Better mobile performance
- Higher conversion rates
[grid] Fast Loading Website Optimized Landing Page Modern Performance UI High Speed Web Experience [/grid]
Why Performance Matters
Users expect websites to load quickly.
Slow websites can cause:
- Poor user experience
- Lower engagement
- Slow interactions
- SEO ranking issues
- Higher bounce rates
Core Performance Factors
Modern web performance mainly depends on:
- Optimized images
- Efficient CSS
- Minimal JavaScript
- Fast rendering
- Lazy loading
- Caching
Optimize Images
Large images can slow down websites significantly.
Developers should:
- Compress images
- Use modern formats like WebP
- Use responsive image sizes
- Lazy load offscreen images
Minify CSS and JavaScript
Minification removes unnecessary spaces and comments from files.
Smaller files load faster in browsers.
[code theme="dark"] style.min.css app.min.js [/code]Use Lazy Loading
Lazy loading delays loading of content until needed.
This improves initial page speed.
[code theme="dark"] loading="lazy" [/code][grid] Lazy Loaded Images Optimized Media Loading Fast Scroll Experience Modern Performance Layout [/grid]
Reduce Heavy Animations
Complex animations can reduce performance on low-end devices.
Prefer GPU-friendly properties like:
[code theme="dark"] transform opacity [/code]Avoid animating:
[code theme="dark"] width height top left [/code]Optimize Fonts
Too many font files increase loading time.
Best practices:
- Use fewer font families
- Load only required font weights
- Use modern font formats
- Preload important fonts
Use Modern Image Formats
| Format | Benefits |
|---|---|
| JPG | Good for photos |
| PNG | Transparency support |
| WebP | Smaller file size |
| AVIF | Better modern compression |
Avoid Large DOM Size
Too many HTML elements can slow rendering performance.
Keep layouts clean and optimized.
Reduce HTTP Requests
Every image, CSS file, and script creates a network request.
Fewer requests usually improve loading speed.
Caching
Browser caching stores files locally to improve repeat visits.
[code theme="dark"] Cache-Control:max-age=31536000 [/code]Performance Tools
Developers use performance tools to measure website speed.
- Google Lighthouse
- PageSpeed Insights
- Chrome DevTools
- WebPageTest
[grid] Lighthouse Performance Audit Core Web Vitals Optimization Fast Mobile Experience Optimized Rendering Speed [/grid]
Core Web Vitals
Core Web Vitals are important performance metrics used by Google.
| Metric | Meaning |
|---|---|
| LCP | Largest Content Paint |
| CLS | Layout Stability |
| INP | Interaction Responsiveness |
Best Practices
- Optimize images and fonts
- Use lazy loading
- Reduce unused CSS and JS
- Use efficient animations
- Keep layouts lightweight
- Test on mobile devices