Validate CSS code or the stylesheets of a page with the W3C validator.
The CSS validator checks your CSS code, a CSS file or the stylesheets of a web page with the W3C CSS Validation Service (CSS3 + SVG profile). It lists the errors – unknown properties, invalid values, syntax mistakes – and the warnings, with their line and context.
Invalid CSS is ignored by browsers, so a typo can silently break part of your design. Validating catches it in seconds.
The official CSS validator.
A snippet, a .css file or a whole page.
Syntax highlighting for your CSS.
With line numbers and context.
The W3C validator can lag behind the newest CSS features and vendor prefixes. Check those against browser support instead.
Not directly, but broken layouts and hidden content affect visitors.
It's sent to the W3C validator for checking and not stored by us.