@media (min-width: 979px) {
  ul.nav li.dropdown:hover > ul.dropdown-menu {
    display: block;
  }
}

#header {
    background-image: url('http://xerobid.com/wp-content/uploads/2014/09/Minecraft-Nature-Gallery-HD-Wallpaper.jpg');
    background-size: cover;
    text-align: center;
}

.threeD {
    font-family: Arial, Helvetica, sans-serif;
    color: #FFFFFF;
    text-shadow: 0 1px 0 #ccc, 0 2px 0 #c9c9c9, 0 3px 0 #bbb, 0 4px 0
    #b9b9b9, 0 5px 0 #aaa, 0 6px 1px rgba(0, 0, 0, .1), 0 0 5px
    rgba(0, 0, 0, .1), 0 1px 3px rgba(0, 0, 0, .3), 0 3px 5px
    rgba(0, 0, 0, .2), 0 5px 10px rgba(0, 0, 0, .25), 0 10px 10px
    rgba(0, 0, 0, .2), 0 20px 20px rgba(0, 0, 0, .15);
}

Move CSS into it's own file
Move CSS into it's own file