Regex Tester & Validator

This regular expression matches Tailwind CSS utility classes that apply specifically to dark mode, such as `dark:bg-gray-800`. It looks for a word boundary and a space, followed by the `dark:` prefix and any valid Tailwind class characters (letters, numbers, hyphens, colons, or underscores). This makes it highly useful for extracting, filtering, or removing dark mode classes from HTML or JSX components in frontend development workflows.