When working with complex CSS selectors that include multiple nested pseudo-selectors like :is(), :where(), :not(), and :has(), maintain consistent formatting and consider breaking long selector chains for better readability. This is particularly important in Svelte components where selectors may need :global() wrappers.

For complex nested selectors, consider adding multiple selector options within pseudo-selectors to improve maintainability:

/* Good: Multiple selectors within :is() for flexibility */
div :is(:global(.class:is(span:is(:hover)), .x)){}

/* Instead of: Single complex nested chain */
div :is(:global(.class:is(span:is(:hover)))){}

This approach makes selectors more maintainable and allows for easier extension when additional selector variants are needed.