/**
 * `css` tagged template literal helper for component styles.
 *
 * Produces a {@link ComponentStyles} payload that can be assigned to
 * {@link ComponentDefinition.styles}. When the host environment supports
 * Constructable Stylesheets, the underlying CSS is shared across all
 * instances via `document.adoptedStyleSheets`; otherwise it falls back to a
 * traditional `<style>` element rendered inside the shadow root.
 *
 * Interpolated values are HTML/CSS-escaped to prevent stylesheet injection.
 *
 * @example
 * ```ts
 * import { component, css, html } from '@bquery/bquery/component';
 *
 * const accent = '#0066cc';
 * component('themed-card', {
 *   styles: css`
 *     :host { display: block; padding: 1rem; }
 *     h2 { color: ${accent}; }
 *   `,
 *   render() { return html`<h2>Hello</h2>`; },
 * });
 * ```
 *
 * @module bquery/component
 */
declare const COMPONENT_STYLES_MARKER: unique symbol;
/**
 * Opaque payload returned by {@link css}.
 *
 * It coerces to its underlying string via `toString()` so that existing
 * `styles: string` consumers continue to work unchanged.
 */
export interface ComponentStyles {
    readonly [COMPONENT_STYLES_MARKER]: true;
    readonly text: string;
    toString(): string;
    /**
     * Construct a shared `CSSStyleSheet` (cached per text) for use with
     * `adoptedStyleSheets`. Returns `null` in environments without support.
     */
    toAdoptableSheet(): CSSStyleSheet | null;
}
/**
 * Type guard: is the given value a {@link ComponentStyles} payload?
 */
export declare const isComponentStyles: (value: unknown) => value is ComponentStyles;
/**
 * Tagged template literal that produces a {@link ComponentStyles} payload.
 */
export declare const css: (strings: TemplateStringsArray, ...values: unknown[]) => ComponentStyles;
/**
 * Attempt to apply a `ComponentStyles` payload to a shadow root via
 * `adoptedStyleSheets`. Returns `true` on success; on failure (no support, or
 * sheet construction failed) callers should fall back to a `<style>` element.
 */
export declare const applyAdoptedStyles: (root: ShadowRoot, styles: ComponentStyles) => boolean;
export {};
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