/**
 * Like `T & U`, but using the value types from `U` where their properties overlap.
 *
 * @internal
 */
export declare type Overwrite<T, U> = Omit<T, keyof U> & U;
declare type GenerateStringUnion<T> = Extract<{
    [Key in keyof T]: true extends T[Key] ? Key : never;
}[keyof T], string>;
/**
 * Generate a set of string literal types with the given default record `T` and
 * override record `U`.
 *
 * If the property value was `true`, the property key will be added to the
 * string union.
 *
 * @internal
 */
export declare type OverridableStringUnion<T, U = Record<any, any>> = GenerateStringUnion<Overwrite<T, U>>;
export declare type BreakpointDefaults = Record<"xs" | "sm" | "md" | "lg" | "xl" | string, true>;
export interface BreakpointOverrides {
    [key: string]: unknown;
}
export declare type Breakpoint = OverridableStringUnion<BreakpointDefaults, BreakpointOverrides>;
export declare type BreakpointValues = {
    [key in Breakpoint]: number;
};
export declare const keys: Breakpoint[];
export interface IBreakpoints {
    keys: Breakpoint[];
    values: BreakpointValues;
    up: (key: Breakpoint | number) => string;
    down: (key: Breakpoint | number) => string;
    between: (start: Breakpoint | number, end: Breakpoint | number) => string;
    only: (key: Breakpoint) => string;
    width: (key: Breakpoint) => number;
}
export declare type BreakpointsOptions = Partial<{
    unit: string;
    step: number;
} & IBreakpoints>;
export declare const createBreakpoints: (breakpoints: BreakpointsOptions) => IBreakpoints;
export {};