Most Taiga UI components rely on  Appearance  directive to represent their interactive state — you will find appearance input on many components, such as  Button  ,  Chip  ,  Notification  etc. 
 When you include Taiga UI theme what you do is define light and dark mode values for CSS  variables  and make built-in appearances, such as primary or outline , available to use in components. 
You can easily create your own appearances with the help of mixins (both LESS and SCSS) to define style rules for particular states:
 Don't forget to import @import '@taiga-ui/core/styles/taiga-ui-local';