How to change the background color of the header?

To resolve this issue, below is our instruction:
Firstly, follow the jetpack’s guideline in the Blog article on how to use Edit CSS here. http://designwall.com/blog/using-jetpack-custom-css-for-your-wordpress-site/
Then add the code to the Edit Css.

#header {    background: #...; }
#header #navigation a {
    color: #...;    
}
#header #navigation a:hover,
#header #navigation a:active,
#header #navigation a:focus {
    text-decoration: none;
    color: #...;
}
#header #navigation li:first-child a {
    border-left-color: #...;
}
#header #navigation li a {
    border-right-color: #...;
}

Hope this helps !