The sky is blue because the blue light from the sun is scattered all over the sky by the atmosphere, so everywhere you look is blue! As the sun gets lower the light’s path through the atmosphere gets longer and reds are scattered too making the sunset colours we all love.
The oceans are blue because of similar reasons, water absorbs and scatters light in such a way that deep water appears blue. Algae and mud can cause other colourings of course!
I think is the opposite way you have mentioned, The sky is blue because of the way the Earth’s atmosphere scatters light from the sun. A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered out and away from the line of sight.
hope my answer is clear