import { Mark, MarkType, Schema } from '../../prosemirror';
export declare class UnderlineMarkType extends MarkType {
    constructor(name: string, rank: number, schema: Schema);
    create(): Mark;
    readonly matchDOMTag: {
        u: null;
    };
    readonly matchDOMStyle: {
        'text-decoration': (value: string) => null | undefined;
    };
    toDOM(): [string];
}
export interface UnderlineMark extends Mark {
    type: UnderlineMarkType;
}
export declare function isUnderlineMark(mark: Mark): mark is UnderlineMark;