No WebGL build function in 2020.3.48f1

Howdy, I'm new to the Unity dev world and am unable to build a project in WebGL. A windows version was built successfully, then switched platform after selecting WebGL--the Build and Build and Run buttons are grayed out. How to ungray them so that I can build the project in WebGL?

There is a warning above the build button that says "In order to build a player, go to Player resolve the incompatibility between the color space and the current settings." And I figured it out...thank you!

Unity 2020 is out of date, and it's not officially supported. Please use Unity 2021.3 at least.

Actually for WebGL you want to be on the latest LTS, if not the latest tech stream because the backend tech is making great strides in recent years.

And be sure to use URP if you are serious about targeting webgl as the main platform, as it will be a lot faster.