Does ETH have a max supply?

I'm curious about the long-term prospects of Ethereum and its underlying token, ETH. One aspect that often attracts investors to a cryptocurrency is the scarcity factor, which is often tied to the maximum supply of the token. So, my question is, does ETH have a maximum supply that is predetermined or is it designed to have an infinite or variable supply over time? Understanding this could help me better evaluate the potential for long-term appreciation of ETH as an investment.