/**
 * HMR handler for `czap:update` messages.
 *
 * Performs surgical DOM updates when `@quantize` CSS or shader
 * uniforms change during development, avoiding full page reloads.
 *
 * @module
 */
declare global {
    interface HTMLCanvasElement {
        /**
         * czap runtime-attached WebGL program for HMR uniform updates.
         * Set by the shader directive when a program is linked.
         */
        __czapProgram?: WebGLProgram;
    }
}
/**
 * Shape of the HMR payload the czap Vite plugin ships over the Vite
 * dev-server WebSocket. Handled by {@link handleHMR} on the client.
 */
export interface HMRPayload {
    /** Message discriminator. Always `'czap:update'`. */
    readonly type: 'czap:update';
    /** Boundary id whose compiled output changed. */
    readonly boundary: string;
    /** New compiled CSS (omitted when only uniforms changed). */
    readonly css?: string;
    /** New shader-uniform values (omitted when only CSS changed). */
    readonly uniforms?: Record<string, number>;
}
/**
 * Handle a czap:update HMR payload.
 * Dispatches to CSS replacement or shader uniform updates based on payload content.
 */
export declare function handleHMR(payload: HMRPayload): void;
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