Hey orange Sky (Your name did make me ponder for a while though... As far as I remember the sky is green.) Now coming back to your question (which was set 5 months prior to my writing this answer, but still I'm gonna write it) Actually, I bumped into that same question as soon as I saw all the paragraph elements in green even after refreshing for thousands of times after a while I found the real reason out.

You see, at the very beginning, we had to set the anchor elements of the page to green color, which is more specific than the body element. That's why even after adding the text color of the body to a specific color, your code doesn't affect the whole body. Hope you find that useful.

The header and nav colors are explicitly set to white:

h1, h2 {
    color:#fff;
}

nav a, nav a:visited {
    color:#fff;
}

Hi orange sky,

The reason for that lies in the selector specificity. True, color for all the body comes later, and it's true that the cascading feature implies overriding earlier values, but in the case of the color, for example, of the headers 1 and 2, the selector used to assign them the color is

h1, h2 {
  color: #fff;
}

That, of course, is more specific than simply "body," because clearly h1 and h2 are parts inside the body.

I am just rephrasing here what Nick explained in another video. You do well in reviewing videos; you may find his explanation.

HTH.