Function lumen_node_closest 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn lumen_node_closest(
    node: LumenNode,
    selector: *const c_char,
    out: *mut LumenNode,
) -> LumenStatus

Nearest ancestor-or-self of node matching selector, written to *out (0 when none). Bad selector returns LumenStatus::ErrCss. Thread-safe.