(** State variants and pseudo-classes *)

(** Variant modifier *)
type t

(** Pseudo-class states *)
type pseudo = [
  | `Hover
  | `Focus
  | `Focus_within
  | `Focus_visible
  | `Active
  | `Visited
  | `Target
  | `Disabled
  | `Enabled
  | `Checked
  | `Indeterminate
  | `Default
  | `Required
  | `Valid
  | `Invalid
  | `In_range
  | `Out_of_range
  | `Placeholder_shown
  | `Autofill
  | `Read_only
]

(** Pseudo-element states *)
type pseudo_element = [
  | `Before
  | `After
  | `First_line
  | `First_letter
  | `Marker
  | `Selection
  | `File
  | `Backdrop
  | `Placeholder
]

(** Structural pseudo-classes *)
type structural = [
  | `First
  | `Last
  | `Only
  | `Odd
  | `Even
  | `First_of_type
  | `Last_of_type
  | `Only_of_type
  | `Empty
  | `Root
  | `Nth of int
  | `Nth_last of int
]

(** Group and peer variants *)
type group = [
  | `Group of pseudo
  | `Peer of pseudo
]

(** Special variants *)
type special = [
  | `Not of pseudo
  | `Has of string
  | `Where of string
  | `Is of string
  | `Starting_style
  | `Inert
  | `Open
  | `In of string
]

(** Apply pseudo-class variant *)
val pseudo : pseudo -> Css.t -> t

(** Apply pseudo-element variant *)
val pseudo_element : pseudo_element -> Css.t -> t

(** Apply structural variant *)
val structural : structural -> Css.t -> t

(** Apply group variant *)
val group : group -> Css.t -> t

(** Apply special variant *)
val special : special -> Css.t -> t

(** Convert to CSS class *)
val to_class : t -> Css.t

(** Apply variant to classes *)
val apply : t -> Css.t -> Css.t

(** Common variants *)
val hover : Css.t -> Css.t
val focus : Css.t -> Css.t
val active : Css.t -> Css.t
val disabled : Css.t -> Css.t
val first : Css.t -> Css.t
val last : Css.t -> Css.t
val odd : Css.t -> Css.t
val even : Css.t -> Css.t
val starting_style : Css.t -> Css.t