I want to: change link / hover color, adjust width, and more

I haven’t dug around CSS in over 10 years, and I gotta say, things have changed quite a bit. So now I’m confused.

I can’t figure out how to change the colors of links, as well as other elements when I hover over them. They’re green now, and there’s a shade of blue I want. I found this bit of code, but it doesn’t do anything for me.

.menu-toggle:hover, .main-navigation.toggled .menu-toggle, .main-navigation a:hover  {
  background: #FFA500;
}

I found code to change the width of the content area, but it doesn’t change the width of the header image. I’m guessing I just need to add something before the brackets, but I’d rather not guess and I’d prefer to hear from you guys.

.page-header, .page-content, .hentry, .entry-thumbnail {
    max-width: 720px;
    width: 100%;
}

Thanks!

The page I need help with: [log in to see the link]