In water, the acid ${\mathrm{HClO}}_4,\mathrm{HCl},{\mathrm{H}}_2{\mathrm{SO}}_4$ and ${\mathrm{HNO}}_3$ exhibit the same strength as they are completely ionised in water (a base). This is called .....of the solvent water.

Leveling effect or solvent transforms buffer impact to solvent influence on acid and base characteristics. The basicity of the solution limits (levels) the power of a levelled fig effect.
The solvent's acidity levels off a strong base's strength.