CSS Formatter

Understanding the Basics

CSS (Cascading Style Sheets) is the language for describing the visual presentation of HTML documents, enabling separation of content from design. Modern CSS codebases grow large quickly — production stylesheets for complex web applications routinely exceed 50,000 lines across hundreds of files. While preprocessors like Sass, Less, and PostCSS help organize CSS with variables and nesting, the compiled output can be difficult to read. Minified CSS delivered by CDNs and build tools strips all whitespace and comments, making it completely unreadable when debugging visual issues in production. A CSS formatter parses the stylesheet and re-serializes it with consistent formatting: one declaration per line, proper indentation inside selector blocks, consistent spacing around colons and braces, and logical grouping of related properties. Well-formatted CSS enables faster code review, makes specificity conflicts easier to spot, and is easier to search through in an editor. Our formatter uses Prettier's CSS formatting engine, which follows the CSS specification closely and handles all modern CSS features including custom properties (CSS variables), @layer, @container queries, @supports, CSS nesting (native, without preprocessors), and media query formatting.

How to Use the Tool

1. Paste your minified or inconsistently formatted CSS into the input editor.
2. The formatter applies Prettier's CSS formatting rules instantly.
3. Each CSS declaration appears on its own line, selector blocks are properly indented, and media queries are expanded for readability.
4. Comments are preserved and repositioned to align with their associated declarations.
5. Download the formatted CSS or copy it to clipboard for your source files.

Key Features & Specifications

• Formats CSS using Prettier's official CSS parser for standards-compliant output
• Supports modern CSS: custom properties, @layer, @container queries, @supports, and CSS nesting
• Handles SCSS and Less syntax in addition to standard CSS
• Preserves and reformats /* comments */ at appropriate positions
• Configurable print width (default 80 characters) and quote style (double/single)

Frequently Asked Questions (FAQ)

Q:Does formatting change any CSS property values?

The formatter only adds whitespace and normalizes quote styles. It does not alter property names, selector specificity, values (color formats, measurements), or the order of declarations or selectors. The output is semantically identical to the input.

Q:Will the formatter fix invalid CSS?

No. The formatter requires syntactically valid CSS as input. If your CSS has unclosed braces or invalid property syntax, the formatter will report a parse error rather than guessing at your intent. Use the CSS validator first if you suspect errors.

Q:Can I format CSS that uses CSS custom properties (--variables)?

Yes. CSS custom properties (--my-color: #ff0000) are treated as standard declarations by the formatter. They are formatted with the same indentation and spacing as regular CSS properties.