This manuscript presents a revised claim-bounded formulation of A10 Civilizational Margin Theory. The theory is not intended as a political program, social-control method, civilization-engineering manual, economic doctrine, or universal theory of human society. Its narrower purpose is to frame civilization-scale overload as a diagnostic problem involving loss of margin, tail-risk accumulation, institutional acceleration, resource stress, and failure-boundary blindness.The revised manuscript treats A10 not as a mandate for further expansion, maximum efficiency, or intensified industrial growth, but as a structured-prior framework for identifying where social, technological, and environmental systems lose recoverable slack. It emphasizes restraint, auditability, claim boundaries, failure-boundary mapping, and the preservation of human margin under uncertainty.The proposed framework remains theoretical and diagnostic. It does not claim empirical validation, policy readiness, predictive authority over societies, or direct applicability to real governance. Its intended contribution is to provide a bounded vocabulary for discussing civilizational stress, structural restraint, and the need to preserve room for humane and reflective forms of life.