Svelte Guideline: Variants — Use tailwind-variants (tv) for component variants. Description: Type-safe variant definitions with tailwind-variants. Do: const buttonVariants = tv({ variants: { size: { sm, md, lg } } }). Don't: Conditional class strings for variants. Good Example: tv({ base: '...', variants: { variant: { default, destructive } } }). Bad Example: class={size === 'sm' ? 'h-9 px-3' : 'h-10 px-4'}. Severity: Medium. Docs: https://www.tailwind-variants.org.