What maintains the stable equilibrium of a star, like our Sun, while it is on the Main Sequence?

Answer

The outward pressure from nuclear fusion perfectly counteracts the inward crushing force of gravity.

During the Main Sequence phase, a star exists in hydrostatic equilibrium where the outward pressure generated by hydrogen fusion in the core precisely balances the inward force exerted by gravity, keeping the size and temperature stable.

What maintains the stable equilibrium of a star, like our Sun, while it is on the Main Sequence?
astronomystarsstellar evolutionred giantsLuminositymain sequence stars