```c title="C"
#include "kreuzberg.h"
#include <stdio.h>

int main(void) {
    const char *config_json =
        "{"
        "\"pdf_options\": {"
        "\"hierarchy\": {"
        "\"enabled\": true,"
        "\"detection_threshold\": 0.75,"
        "\"ocr_coverage_threshold\": 0.8,"
        "\"min_level\": 1,"
        "\"max_level\": 5"
        "}"
        "}"
        "}";

    KREUZBERGExtractionConfig *config = kreuzberg_extraction_config_from_json(config_json);
    if (!config) {
        fprintf(stderr, "config parse failed (code %d): %s\n",
                kreuzberg_last_error_code(),
                kreuzberg_last_error_context());
        return 1;
    }

    KREUZBERGExtractionResult *result =
        kreuzberg_extract_file_sync("document.pdf", NULL, config);
    if (!result) {
        fprintf(stderr, "extraction failed (code %d): %s\n",
                kreuzberg_last_error_code(),
                kreuzberg_last_error_context());
        kreuzberg_extraction_config_free(config);
        return 1;
    }

    char *content = kreuzberg_extraction_result_content(result);
    printf("%s\n", content ? content : "(empty)");
    kreuzberg_free_string(content);

    kreuzberg_extraction_result_free(result);
    kreuzberg_extraction_config_free(config);
    return 0;
}
```