From another point of view, the oceans are just a thin film of water clinging to the surface of this ball of rock.
The depth of the oceans is a rounding error compared to the depth of the planet.
If the Earth were the size of a basketball, it wouldn’t even feel wet to the touch because of how thin the oceans would be relatively. Scales are wild
And a continent is just a really big island.
Therefore a continent is actually just a big mountain.
And the oceans are just really big valleys filled with water
But mostly underwater.
Salt lakes typically have rivers containing trace amounts of salt flowing into them but no rivers flowing out. That means the only way water can leave is through evaporation, but the salts get left behind and the salinity therefore builds up.
I learned this in Geography 101. Then I had a shower thought that the oceans of the world are just a giant salt lake.
And the sea is just a big lake. The sea floor a long valley. Fish are valley people. Land animals are mountain folk.
This is literally true (Hawaii) except when it isn’t (Key West)