Svelte Guideline: Variants — Use cn() for class merging. Description: clsx + tailwind-merge for conditional class composition. Do: cn('base-class', conditional && 'extra', props.class). Don't: String concatenation for classes. Good Example: cn('flex items-center', variant === 'ghost' && 'bg-transparent'). Bad Example: 'flex items-center ' + (variant === 'ghost' ? 'bg-transparent' : ''). Severity: Medium. Docs: .