Are there any laptops out there that do not sport any air cavities or vents in their body? I am trying to buy a laptop that operates in a very humid, sea-facing environment. Lost a few machines due to rust if they were left switched off for a month or so! Basically, I don't want any air entering the laptop, but don't know if it is possible even with the Core M machines. Macbook 12 inch advertises it has no air vents, but I can't verify that right now. Are there other options as well? Thank you so much!