Collapsing header issue

Hello im trying to create a collapsing header such as this . However i am struggling to understand and transfer it to my Landscape child theme.. here is a landscape theme which has the effect in use for reference. I don’t a domain yet so i cant link it here but below is the code from my style.css that is related to it.

Any help would be greatly appreciated!

/* =Header
----------------------------------------------- */

#masthead {
	background:#111 url(images/default-header.jpg ) center 0 no-repeat;
	margin-top: 0;
	padding-bottom: 0;
	max-width: 100%;
	height: auto;
	position: relative;
	background-attachment: fixed;
}
.admin-bar #masthead {
	background-position: center 28px;
}
#masthead #logo{
	width:100%;
	margin:0 auto;
	text-align:center;
	position:absolute;
	top:250px;
}

h1.site-title {
	font-size: 0px;
	font-style: normal;
	padding:0;
	font-weight:normal;
	line-height: 1.2;
	position: relative;
	font-family: georgia, serif;
	text-shadow:1px 1px #111;
}
.site-title a,
.site-title a:hover,
.site-title a:visited,
.site-description {
	color: #fff;
	text-decoration:none;
}
.site-title a:hover{
	filter:alpha(opacity=90);
	-moz-opacity:0.9;
	-khtml-opacity: 0.9;
	opacity: 0.9;
}
h2.site-description {
	font-style: italic;
	padding: 0;
	max-width: 70%;
	margin: 0 auto;
	text-align: center;
	font-size: 17px;
	font-family:georgia, arial;
}

/* =Menu
----------------------------------------------- */

.main-navigation {
	display: block;
	float: left;
	width: 100%;
	font-family: georgia, arial;
	text-transform:uppercase;
	background:#000;
	z-index: 99999;
	-moz-box-shadow: 0 1px 1px rgba(0,0,0,0.2);
	-webkit-box-shadow: 0 1px 1px rgba(0,0,0,0.2);
	box-shadow: 0 1px 1px rgba(0,0,0,0.2);
	clear:left;
	font-size:14px;
}

.main-navigation a{
	color:#fff;
}
.main-navigation ul {
	float: right;
    list-style: none;
    margin: 0;
    padding-left: 0;
    position: relative;
    right: 50%;
}
.main-navigation ul li {
	display: inline-block;
	position: relative;
	left: 50%;
}
.main-navigation ul li:after {
	color: #666;
	content: "|";
	display: inline;
	font-size: 12px;
	margin: 0 0 0 17px;
	font-style:italic;
}
.main-navigation ul li:last-child:after {
	content: normal;
	margin: 0;
	padding: 0;
}
.main-navigation ul ul li {
	float: left;
	left: auto;
	font-style:normal;
}
.main-navigation ul a {
	display: inline-block;
	text-decoration: none;
	padding: 10px 6px 10px 21px;
	font-style:normal;
}
.main-navigation ul ul a {
	color: #999;
}
.main-navigation ul ul {
	-moz-box-shadow: 0 1px 1px rgba(0,0,0,0.2);
	-webkit-box-shadow: 0 1px 1px rgba(0,0,0,0.2);
	box-shadow: 0 1px 1px rgba(0,0,0,0.2);
	background: #000;
	display: none;
	float: left;
	position: absolute;
		top: auto;
		left: 10px;
		right: auto;
	text-align: left;
	z-index: 99999;
}

.main-navigation ul ul ul {
	left: 100%;
	top: 0;
}
.main-navigation ul ul a {
	width: 150px;
	font-size: 15px;
	padding: 7px 15px;
}
.main-navigation ul ul li:after {
	content: normal;
	margin: 0;
	padding: 0;
}
.main-navigation li:hover > a {
	color: #999;
}
.main-navigation ul ul :hover > a {
	color: #fff;
}
.main-navigation ul ul a:hover {
}
.main-navigation ul li:hover > ul {
	display: block;
}
.main-navigation li.current_page_item a,
.main-navigation li.current-menu-item a {
	color: #999;
}

/* Small menu */
.main-small-navigation {
	background:#000;
	margin: 0;
	padding: 0.5em 0 0;
	z-index:99999;
	position:fixed;
	width:100%;
}
.menu-toggle {
	color: #fff;
	cursor: pointer;
	font-size: 20px;
	text-align: center;
}
.main-small-navigation .menu {
	display: none;
}
.main-small-navigation .menu,
.main-small-navigation .menu a {
	color: #fff;
}
.main-small-navigation ul{
	z-index:9999;
}
.main-small-navigation ul li{
	list-style-type:none;
}

/* =Content
----------------------------------------------- */

.sticky {
}
.entry-title, .entry-title a{
	text-decoration:none;
	font-size:38px;
	color:#000;
	text-transform:capitalize;
	text-align:center;
}
.entry-title a:hover{
	text-decoration:none;
	color:#666;
}
.archive-title{
	margin-bottom:15px;
	font-size:22px;
	text-transform:uppercase;
	color:#999;
	text-align:center;
}
.hentry {
	margin:0 0 80px 0;
	padding:0 0 80px;
	border-bottom:4px double #e6e6e6;
}
.entry-meta {
	clear: both;
	text-align:center;
	font-family: georgia, serif;
	font-style:italic;
	margin:20px 0;
}
.entry-meta a{
	text-decoration:none;
	color:#999;
}
.sep{
	color:#e6e6e6;
	font-style:italic;
}
.byline {
	display: none;
}
.single .byline,
.group-blog .byline {
	display: inline;
}
.entry-content,
.entry-summary {
	margin: 1.5em 0 0;
}
.page-links {
	clear: both;
	margin: 0 0 1.5em;
}
.single-thumbnail{
	margin:20px 0;
}
.single-thumbnail img:hover{
	filter:alpha(opacity=90);
	-moz-opacity:0.9;
	-khtml-opacity: 0.9;
	opacity: 0.9;
}