There are two rules you can add that will affect the amount of space between the header and the top of the page:
.home #page:before {
height: 35px;
}
.home #page {
margin-top: 2em;
}
The values listed are the current values. Reduce them as desired. I would probably start on the first rule, first, and if 0 isn’t small enough, adjust the second rule. For the second rule, values can be listed in px (pixels) or em, which is basically the equivalent of the height of the current font, i.e., 1em is the same size as the current font, 2em would be twice the size of the current font. Fractional values can also be used, like 1.5em. Pixels (px) requires whole numbers. If you use 0 for either of the two values, you can leave off the units (px or em).