Validate Your CSS Code Online Validate CSS syntax with checks for property names, value formats, and selector structure.

The tool works by using regular expressions to remove comments from the input CSS code, and then analyzing the resulting string for balanced braces and parentheses. It uses a simple state machine to count the number of opening and closing brackets, detecting any mismatches that could indicate an error. This analysis is performed on the trimmed input string, which has been processed by the `validateCss` function to remove any unnecessary whitespace.

The tool also uses JavaScript's built-in string splitting and matching methods, such as `split()` and `match()`, to extract specific parts of the CSS code, like rule blocks, selectors, and declarations. For example, it splits the input string into individual rule blocks using the `}` character as a delimiter, and then further splits each block into its constituent parts, like selector and declaration. This allows it to count the total number of selectors, rules, and declarations in the CSS code.

In addition to this basic analysis, the tool checks for common issues like missing colons in declarations, vendor prefixes, and the use of `!important`. It does this by using regular expressions to search for specific patterns in the input string, such as lines that contain a colon or lines that start with a vendor prefix. If it finds any matches, it adds a warning message to the result object, which is then displayed to the user. The tool also uses React's `useState` and `useCallback` hooks to manage its internal state and handle user input.

The tool's output includes detailed information about the CSS code, such as the number of rule blocks, total selectors, and total declarations. It also provides warnings and suggestions for improvement, making it a useful tool for front-end developers and web designers who want to ensure their CSS code is error-free and follows best practices. The use of specific technologies like React and JavaScript's built-in string methods allows the tool to provide a high level of accuracy and detail in its analysis.