A strong acid or base dissociates completely. Slide the concentration and read pH, pOH, [H⁺] and [OH⁻]. They always satisfy pH + pOH = 14 and [H⁺][OH⁻] = Kw = 1.0×10⁻¹⁴.
Try: drag the acid down to 10⁻⁸ M. The pH does not exceed 7 — water's own autoionization keeps [H⁺] near 10⁻⁷, so a hugely dilute strong acid is still (barely) acidic, never basic.