Core knowledge points of CSS3

The CSS3 Basics section covers the history of CSS3, browser compatibility handling, selector enhancements, the box model, the visual formatting model, media queries, CSS variables, preprocessors and postprocessors, performance optimization, and code organization methods. The Layout & Typography chapter details Flexbox, Grid, multi-column layouts, positioning, floats, responsive design, viewport units, classic layout solutions, equal-height columns, sticky positioning, alignment methods, overflow handling, scroll snapping, subgrid, and size control. The Visual Effects module includes transitions, keyframe animations, 2D/3D transformations, gradients, shadows, filters, blend modes, clipping and masking, border images, enhanced backgrounds, shape wrapping, 3D space, animation optimization, scroll animations, and parallax effects. The Text & Fonts chapter explains custom fonts, text shadows, overflow handling, typography properties, font icons, variable fonts, text decoration, writing modes, alignment and spacing, drop caps, text gradients, strokes, line breaks, hyphens, text direction, and more. The Responsive Design section explores media queries, mobile-first approaches, breakpoint selection, responsive images, adaptive tables, navigation patterns, device adaptation, viewport control, responsive fonts, touch targets, high-DPI adaptation, print styles, dark mode, and orientation-aware component design. The CSS3 Advanced Features include counters, pseudo-classes, pseudo-elements, attribute selectors, custom properties, shape paths, blend modes, masking, clipping, filter chains, variable theming, conditional rules, scoped styles, native nesting, container queries, cascade layers, and scoped styles.

The application of operations and functions

In CSS, operations and functions greatly enhance the flexibility and dynamism of style design. Basic operations like addition, subtraction, multiplication, and division can be directly applied to property values using the `calc()` function for precise calculations. Custom functions, created via `@function`, enable reusable complex logic such as unit conversion and color mixing. Combined with CSS variables, they facilitate responsive layouts and dynamic style adjustments. Conditional operations simulate conditional logic using functions like `clamp()`, `min()`, and `max()`. Complex functions are widely used in `transform` and gradients but require performance optimization to avoid excessive computation. Practical examples demonstrate the implementation of responsive grids and dynamic shadows, while browser compatibility must be considered with appropriate fallback solutions. Together, these features enhance CSS's dynamic expressiveness and development efficiency.

The advantages of nested rules

CSS preprocessors simplify style writing by nesting rules that mimic HTML structure, reducing repetitive code and improving readability. They allow defining child element styles within parent selectors, support referencing parent selectors using symbols (like `&`), and facilitate handling pseudo-classes and modifiers. Nested rules also support media queries, making responsive design code more centralized and modular, while reducing naming conflicts. They can be combined with methodologies like BEM to maintain clear structure and avoid excessive nesting, which may lead to overly complex selectors and performance issues. Additionally, nested rules work with variables to create dynamic styling systems, making them ideal for component-based development, interactive states, responsive design, and large-scale projects—keeping style hierarchies clear and organized.

The creation and application of mixed macros

Mixins are a powerful feature in CSS preprocessors that allow developers to define reusable style blocks and reference them across multiple selectors. Mainstream preprocessors like Sass, Less, and Stylus all support mixins but with slight syntax differences. Mixins enhance flexibility by accepting parameters, supporting default values, variables, or expressions, and can incorporate conditional logic and loops to implement complex functionalities such as responsive breakpoints and grid systems. Through content blocks, mixins can receive style blocks, enabling patterns similar to decorators. Practical use cases include creating triangle arrows and shorthand methods for flex layouts. For performance optimization, it is recommended to avoid excessive nesting, split mixins with many parameters, and use placeholder selectors for high-frequency styles. Mixins can also work in tandem with modern features like CSS variables and functions. Common troubleshooting includes handling browser prefixes and simplifying media queries. Advanced patterns involve dynamic selector generation and mixin patterns in CSS-in-JS.

The selection of responsive breakpoints

In responsive design, choosing appropriate breakpoints is crucial for a website's performance across different devices. Breakpoints should be set based on content layout changes rather than specific device dimensions. Mainstream strategies include device-based breakpoints and the superior content-first approach. Common breakpoint ranges can serve as references but should be adjusted according to actual needs. Using CSS preprocessors or variables to manage breakpoints improves maintainability. Mobile-first and desktop-first are the two primary design strategies. Complex layouts require precise breakpoint control, and typography also needs responsive adjustments. Testing tools and real-device testing are indispensable. Advanced techniques include container queries and hybrid breakpoint strategies. Excessive breakpoints can impact performance, so optimization is necessary. Documenting breakpoints aids team collaboration. Future devices like foldable screens present new challenges for responsive design.

Media queries for device characteristics

Media queries are a powerful feature in CSS3 that allow developers to apply different style rules based on device characteristics such as viewport width, screen orientation, resolution, etc., enabling the creation of responsive designs. The basic syntax uses the `@media` rule followed by media feature expressions. Common features include viewport width, device orientation, and resolution queries, which support combining multiple conditions. Modern CSS introduces range syntax, interaction capability detection, and color capability detection. Practical applications include responsive navigation bars, adaptive font sizes, and dark mode support. For performance optimization, it is recommended to avoid excessive breakpoints, adopt a mobile-first approach, and use media queries alongside container queries—the latter adjusts styles based on container dimensions. In terms of browser compatibility, modern browsers support media queries well, but newer features may require consideration for backward compatibility. Feature detection can be used to ensure compatibility.

Viewport-related media features

Viewport-related media features are core tools in responsive design, allowing developers to apply different CSS styles based on device viewport dimensions, orientation, and other conditions. Key features include `width` and `height` for matching viewport width and height (with specific values or ranges), `aspect-ratio` for matching width-to-height ratios, `orientation` for detecting landscape or portrait mode, and `resolution` for matching pixel density. `viewport-width` and `viewport-height` target viewport dimensions. The article details the syntax and usage examples of these features, covering common breakpoint practices, performance optimization techniques, and comparisons with container queries. It also provides methods for detecting viewport conditions via JavaScript. Practical applications include responsive navigation bars, image grid layouts, font adjustments, and debugging tips. Future trends like dynamic range media queries and `prefers-reduced-motion` are also discussed.

The basic syntax of media queries

Media queries are an important feature of CSS3 that allow applying different style rules based on device characteristics. The basic syntax consists of the `@media` rule, which includes media types and feature expressions. Common media types include `all`, `screen`, `print`, and `speech`. Media features include viewport dimensions, orientation, resolution, etc., and support logical operators like `and`, commas (`,`), and `not`. Common breakpoints are set for different device sizes. Modern CSS introduces range syntax to simplify writing. Practical applications, such as responsive navigation bars, require attention to performance issues. Browser support is generally good, and detection via JavaScript is possible. Advanced features like dark mode adaptation, reduced motion, and emerging container query technology were also introduced.

The principle of hardware acceleration

Hardware acceleration leverages the GPU to enhance graphics rendering performance in CSS by triggering specific properties such as 3D transforms and the `will-change` property, creating independent rendering layers to optimize animations and transitions. Properties that automatically trigger hardware acceleration include `translate3d` and `opacity`, while 2D transforms require special handling like `translateZ(0)`. The `will-change` property should be used cautiously to avoid excessive memory consumption. Practical applications include scroll performance optimization and animation performance improvement, but improper use can lead to increased memory usage or font blurring issues. Mobile devices require special consideration, and browser implementations vary. Best practices involve using it on-demand and testing for validation. CSS animations are the primary use case, offering superior performance compared to traditional animations.

Handling browser prefixes for animations

Browser prefixes are specific identifiers added before CSS properties to provide experimental support before standard property implementation. Different browsers use different prefixes, such as -webkit-, -moz-, -ms-, and -o-. These prefixes allow browser vendors to test new features without affecting the final standard. Common prefixed properties related to animations include @keyframes, animation and its sub-properties, as well as transform and transition. The use of prefixes in modern browsers is declining, as most now support unprefixed properties, but WebKit browsers still require the -webkit- prefix. Mobile WebViews often need prefixes as well. Automated tools like PostCSS with Autoprefixer can simplify prefix handling. For keyframe animations, prefix matching must be noted. Performance optimization should avoid excessive prefix usage, and progressive enhancement is recommended—write standard properties first, followed by prefixed ones. Special prefix handling is needed for 3D transforms and animation performance optimization. Testing and validation can be done via developer tools or JavaScript detection. The future trend is reduced prefix usage, with more feature detection through @supports rules.