Hey everyone,
I taught myself html and css using John Duckett's book last week. I have no coding experience and am looking for someone to do a quick review of the website im building.
heads up: it is probably a disgrace to the css community but I tried my best.

The website is an online guitar tuner. As of now the only fully working page is the homepage. Im waiting to get some feedback on what I have so far before I try and finish up the pages for the other tunings.

html:
Code:
<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title>tunuh</title>
		<link href="stylesheets/style.css" rel="stylesheet" />
		<script language="javascript" type="text/javascript">
			function playSound(soundfile) {
			document.getElementById("dummy").innerHTML=
			"<embed src=\""+soundfile+"\" hidden=\"true\" autostart=\"true\" loop=\"true\" preload=\"true\" />";
			}
		</script>
	</head>
	
	
	
	
	<body>
		<div id="top-bar">
			
		</div>
			<div id="top-nava">
				<div id="main">
				
				<p id="title-bar">
				<span id="logo"><a href="http://www.tunuh.com"><img src="https://s3.amazonaws.com/tuning-website/images/logo.png" alt="my image"></a>
				<span id="button-bar">
				<a href="#"><img src="https://s3.amazonaws.com/tuning-website/images/buttons/guitar-arrow.png" alt="my image"></a>
				<a href="#"><img src="https://s3.amazonaws.com/tuning-website/images/buttons/bass.png" alt="my image"></a>
				<a href="#"><img src="https://s3.amazonaws.com/tuning-website/images/buttons/tones.png" alt="my image"></a>
				</span>
			</p>
				
				
					<div id="app">
						<div id="applet">
							<nav id="nav-bar" class="ztop">
								<ul>
									<li><a href="#">Standard</a></li>
									<li><a href="#">Open</a>
										<ul>
											<li><a href="#">Major</a>	
												<ul>
													<li><a href="#">A</a></li>
													<li><a href="#">B</a></li>
													<li><a href="#">C</a></li>
													<li><a href="#">D</a></li>
													<li><a href="#">E</a></li>
													<li><a href="#">F</a></li>
													<li><a href="#">G</a></li>
												</ul>
											</li>
											<li><a href="#">Minor</a>
												<ul>
													<li><a href="#">A<i>m</i></a></li>
													<li><a href="#">C<i>m</i></a></li>
													<li><a href="#">D<i>m</i></a></li>
													<li><a href="#">E<i>m</i></a></li>
													<li><a href="#">F<i>m</i></a></li>
													<li><a href="#">G<i>m</i></a></li>
												</ul>	
											</li>
										</ul>
									</li>		
									<li><a href="#">Dropped</a>
										<ul>
											<li><a href="#">  A  </a></li>
											<li><a href="#">  C  </a></li>
											<li><a href="#">  D  </a></li>
										</ul>	
									</li>	
									<li><a href="#">Downtuned</a>
										<ul>
											<li><a href="#">E<i>b</i></a></li>
											<li><a href="#">D</a></li>
											<li><a href="#">D<i>b</i></a></li>
											<li><a href="#">C</a></li>
											<li><a href="#">B</a></li>
											<li><a href="#">B<i>b</i></a></li>
										</ul>
									</li>
									<li><a href="#" id="donate">Donate</a></li>
								</ul>
							</nav>
							<nav id="title">
								<ul id="title-box">
									<li id="title-text">Standard</li>
								</ul>
							</nav>
							<nav>
								<div class="tabs" id="play-bar">
									<div class="tab">
										<input type="radio" id="tab-1" name="tab-group-1" checked onclick="playSound('#');">
										<label for="tab-1">Stop</label>
									</div>
					           		<div class="tab">
						           		<input type="radio" id="tab-2" name="tab-group-1" onclick="playSound('https://s3.amazonaws.com/tuning-website/notes/1-e.wav');">
						           		<label for="tab-2">E</label>
						           	</div>
						           	<div class="tab">
					           			<input type="radio" id="tab-3" name="tab-group-1" onclick="playSound('https://s3.amazonaws.com/tuning-website/notes/1-a.wav');">
					           			<label for="tab-3">A</label>
					           		</div>
					           		<div class="tab">
					           			<input type="radio" id="tab-4" name="tab-group-1" onclick="playSound('https://s3.amazonaws.com/tuning-website/notes/2-d.wav');">
					           			<label for="tab-4">D</label>
					           		</div>
					           		<div class="tab">
						           		<input type="radio" id="tab-5" name="tab-group-1" onclick="playSound('https://s3.amazonaws.com/tuning-website/notes/2-g.wav');">
						           		<label for="tab-5">G</label>
						           	</div>
						           	<div class="tab">
					           			<input type="radio" id="tab-6" name="tab-group-1" onclick="playSound('https://s3.amazonaws.com/tuning-website/notes/2-b.wav');">
					           			<label for="tab-6">B</label>
					           		</div>
					           		<div class="tab">
					           			<input type="radio" id="tab-7" name="tab-group-1" onclick="playSound('https://s3.amazonaws.com/tuning-website/notes/3-e.wav');">
					           			<label for="tab-7">e</label>
					           		</div>
					           	</div>	
							</nav>
						</div>
					</div>	
				<p id="footer">
					<!-- Contact us: admin@tunuh.com -->
				</p>
				</div>
			</div>
		<span id="dummy"></span>
	</body>
</html>
css:
Code:
body, div, h1, h2, h3, h4, h5, h6, p, ul, ol, li, dl, dt, dd, img, form, fieldset, input, textarea, blockquote {
	margin: 0; padding: 0; border: 0;
}

body {
	background: #909eab url(https://s3.amazonaws.com/tuning-website/images/concrete_wall.png);
	font-family: Helvetica, sans-serif; font-size: 18px; line-height: 24px;
}

nav {
	margin: 30px auto; 
	text-align: center;
}

nav ul ul {
	display: none;
}

	nav ul li:hover > ul {
		display: block;
	}


nav ul {
	background: #efefef; 
	background: linear-gradient(top, #efefef 0%, #bbbbbb 100%);  
	background: -moz-linear-gradient(top, #efefef 0%, #bbbbbb 100%); 
	background: -webkit-linear-gradient(top, #efefef 0%,#bbbbbb 100%); 
	box-shadow: 0px 0px 9px rgba(0,0,0,0.15);
	padding: 0 20px;
	border-radius: 0px;  
	list-style: none;
	position: relative;
	display: inline-table;
}
	nav ul:after {
		content: ""; clear: both; display: block;
	}

	nav ul li {
		float: left;
	}
		nav ul li:hover {
			background: #4b545f;
			background: linear-gradient(top, #4f5964 0%, #5f6975 40%);
			background: -moz-linear-gradient(top, #4f5964 0%, #5f6975 40%);
			background: -webkit-linear-gradient(top, #4f5964 0%,#5f6975 40%);
		}
			nav ul li:hover a {
				color: #efefef;
			}
		
		nav ul li a {
			display: block; padding: 25px 40px;
			color: #757575; text-decoration: none;
		}
			
		
	nav ul ul {
		background: #5f6975; border-radius: 0px; padding: 0;
		position: absolute; top: 100%;
	}
		nav ul ul li {
			float: none; 
			border-top: 1px solid #6b727c;
			border-bottom: 1px solid #575f6a; position: relative;
		}
			nav ul ul li a {
				padding: 5px 40px;
				color: #efefef;
			}	
				nav ul ul li a:hover {
					background: #4b545f;
				}
		
	nav ul ul ul {
		position: absolute; left: 100%; top:0;
	}


.button {
	padding-left: 7px;
	padding-right: 7px;
	padding-top: 30px;
	padding-bottom: 30px;
	border-right: 1px solid #bfbfbf;
	
}

.tabs {
	position: relative;   
	min-height: 200px;
	clear: both;
	margin: 25px 0;
	background: #efefef; 
	background: linear-gradient(top, #efefef 0%, #bbbbbb 100%);  
	background: -moz-linear-gradient(top, #efefef 0%, #bbbbbb 100%); 
	background: -webkit-linear-gradient(top, #efefef 0%,#bbbbbb 100%); 
	box-shadow: 0px 0px 9px rgba(0,0,0,0.15);
	padding-top: 60px;
	padding-bottom: 60px;
	padding-left: 20px;
	padding-right: 20px;
	border-radius: 0px;  
	list-style: none;
	position: relative;
	display: inline-table;

}
.tab {
	float: left;
}

.tab label {
  	 
  	padding-bottom: 62px;
  	padding-top: 61px;
  	padding-left: 45px;
  	padding-right: 45px;
  	margin-left: -1px; 
  	position: relative;
  	left: 1px; 
  	color: #757575; text-decoration: none;
}

.tab label:hover {
			backgrond: #4b545f;
			background: linear-gradient(top, #4f5964 0%, #5f6975 40%);
			background: -moz-linear-gradient(top, #4f5964 0%, #5f6975 40%);
			background: -webkit-linear-gradient(top, #4f5964 0%,#5f6975 40%);
			color: #efefef;

}

.tab [type=radio] {
  	display: none;   
}
.content {
  	padding:;
  	border: 
}
[type=radio]:checked ~ label {
  	background: #5f564b;
  	background: linear-gradient(top, #5f564b 0%, #756b5f 40%);
  	background: -moz-linear-gradient(top, #5f564b 0%, #756b5f 40%);
  	background: -webkit-linear-gradient(top, #5f564b 0%, #756b5f 40%);
  	color: #efefef;
  	z-index: 2;
  	
}
[type=radio]:checked ~ label ~ .content {
  	z-index: 1;
  	color: #efefef;
}


#main {
	position: relative;
	Width: 1000px;
	height: 600px;
	margin-left: auto;
	margin-right: auto;
	bottom: 100px;
}

#app {
	position: relative;
	width: 900px;
	height: 400px;
	margin-left: auto;
	margin-right: auto;
	top:130px;
	background:rgba(0,0,0,0.2);
	
	
	
}

#applet {
	position: relative;
	margin-left: auto;
	margin-right: auto;
	bottom: 45px;
	border-radius: 0px;
}


#title {

	position:relative;
	left:300px ;
	top:11px;
}

title-box {
	border-radius: 2em 1em 4em / 0.5em 3em;
}

#title-text {
	margin-bottom: 20px;
	color: #757575; text-decoration: none;
	
}


#title-text:hover {
	background: none;

	
}




#donate {
	background: #4b545f;
	background: linear-gradient(top, #4b5f56 0%, #5f756b 40%);
	background: -moz-linear-gradient(top, #4b5f56 0%, #5f756b 40%);
	background: -webkit-linear-gradient(top, #4b5f56 0%,#5f756b 40%);
	color: #efefef;

}

#donate:hover {
	background: #4b545f;
	background: linear-gradient(top, #644f59 0%, #755f69 40%);
	background: -moz-linear-gradient(top, #644f59 0%, #755f69 40%);
	background: -webkit-linear-gradient(top, #644f59 0%,#755f69 40%);
	color: #efefef;
}

#nav-bar {
	position: relative;
	z-index: 5;
}

#play-bar {
	position: relative;
	bottom: 69px;
}


#top-bar {
background-color: #000;
height: 70px;
float: none;
}

#title-bar {
	position: relative; 
	text-align: center;
	float: left;
	left:130px;
	width: 800px;
	height: 100px;
	bottom: 30px;

}

#button-bar {
position: relative;
top:15px;
left: 250px;
	 
}

#selected a {
	background: #000; 
	border-radius: 0px; 
	border-color: #dbdbdb;
	text-decoration: none;
	color: #f3f3f3;
	border: solid 1px #dbdbdb;

	 
}

.top-link {
	position: relative;
	top: 20px;
	padding-top: 7px;
	padding-bottom: 7px;
	padding-left: 30px;
	padding-right: 30px;
}

#logo {
	position: relative;
	top: 40px;
	margin-right: 300px;
}

#footer {
	position: relative;
	top:300px;
	text-align: center;
}