Superpowers, major powers, and regional navies

Which countries are current superpowers, major powers, or major regional powers, and what separates those categories?

Global reach, nuclear power, logistics, bases, and the ability to sustain deployed forces matter more than ship totals alone.

The United States is the only state in this classification that combines global conventional reach with superpower-scale nuclear forces. Russia and China possess the latter without the same expeditionary system. Britain and France sit below that level because their overseas bases, carrier forces, and logistics still permit substantial global action. India, Pakistan, Germany, Italy, Brazil, Turkey, Japan, and South Korea illustrate different combinations of nuclear status, regional strength, and deployable conventional power.