Well done! The style for the different link states look really nice. There is one thing missing:
Give the first paragraph after each heading in the <section> a little bit of text-indentation, say 20px.
Do you know which property could be used for that?
All other pseudo classes overwrite :active if they have (at least) the same specificity. What you could do is adding nav ul li a:active to the existing a:active. Since this has higher specificity it works even though it is above the other nav link pseudo classes.
a:active, nav ul li a:active {
color: #ea6e0e;
background: #a10505;
}