To build this low-profile shelter, select a heavy-duty, opaque fifty-to-sixty-quart under-bed plastic storage box measuring approximately six to eight inches in total height. Line the long, shallow floor with a half-inch sheet of high-density closed-cell foam or foil-backed insulation board. Because vertical height is limited, cut custom-fitted half-inch foam strips to line all four interior sidewalls, securing them with foam-compatible spray adhesive. Cut a five-inch circular opening on one of the narrow end walls, keeping the bottom edge two inches above the container floor to retain the straw bedding inside. Seal the circular opening with waterproof foil tape to cover sharp plastic edges. Fill the shallow living area with a dense layer of dry straw, snap the low-profile lid down, and slide the entire unit under a deck, porch, or outdoor stairway, propping the base up on cedar wood shims to prevent ground moisture absorption.