The error is that you don’t need to self close those meta tags in html5 otherwise there is no problem.
The doctype you are using is for very old phone such as mobile phones before the smartphone generation as part of the “WAP 2.0” stack. If you want to support those devices then you should only use the features that that doctype allows which I believe is a small subset of html and css and certainly not the css3 features you are ploughing aimlessly into your code. Read this thread for more info especially the replies form Alex.
If you want to support modern devices then use modern doctype (htm4.01, xhxtml1,0 or html5)
If you want a full height background then apply the gradient to the body element andf then set html and body to height:100%.
html,body{height:100%}
body {
background: #1f8cc4; /* Old browsers */
/* IE9 SVG, needs conditional override of 'filter' to 'none' */
background: -moz-linear-gradient(top, #1f8cc4 0%, #073d85 60%, #073d85 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%, #1f8cc4), color-stop(60%, #073d85), color-stop(100%, #073d85)); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(top, #1f8cc4 0%, #073d85 60%, #073d85 100%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(top, #1f8cc4 0%, #073d85 60%, #073d85 100%); /* Opera 11.10+ */
background: -ms-linear-gradient(top, #1f8cc4 0%, #073d85 60%, #073d85 100%); /* IE10+ */
background: linear-gradient(top, #1f8cc4 0%, #073d85 60%, #073d85 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#1f8cc4', endColorstr='#073d85', GradientType=0 ); /* IE6-8 */
}
Here is the full working demo: (in html 4.01 this time)
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Main page</title>
<link href="lav.css" rel="stylesheet" type="text/css" media="screen, projection" >
<style type="text/css">
html,body{height:100%}
body {
background: #1f8cc4; /* Old browsers */
/* IE9 SVG, needs conditional override of 'filter' to 'none' */
background: -moz-linear-gradient(top, #1f8cc4 0%, #073d85 60%, #073d85 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%, #1f8cc4), color-stop(60%, #073d85), color-stop(100%, #073d85)); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(top, #1f8cc4 0%, #073d85 60%, #073d85 100%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(top, #1f8cc4 0%, #073d85 60%, #073d85 100%); /* Opera 11.10+ */
background: -ms-linear-gradient(top, #1f8cc4 0%, #073d85 60%, #073d85 100%); /* IE10+ */
background: linear-gradient(top, #1f8cc4 0%, #073d85 60%, #073d85 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#1f8cc4', endColorstr='#073d85', GradientType=0 ); /* IE6-8 */
}
h1 {
font:100px 'Homestead Display', Arial, Helvetica, sans-serif;
color:#fff;
text-align:center;
}
#container {
width:98%;
margin:0 auto;
color:#fff;
font-family:arial, helvetica, "sans serif";
font-size:12pt;
white-space: nowrap;
}
.denied {
font:70px 'Homestead Regular', Arial, Helvetica, sans-serif;
color:#fff;
text-align:right;
position:absolute;
}
#dugme {
margin:20px;
padding-bottom:20px;
text-align:center;
white-space: nowrap;
position:relative;
z-index:3;
}
.lav {
display:inline-block;
width:183px;
height:79px;
border:1px solid #729fc9;
text-align:center;
font:53px/79px 'Wisdom', Arial, Helvetica, sans-serif;
color:#fff;
text-decoration:none;
margin-left: auto;
margin-right: auto;
background: -moz-linear-gradient(left, rgba(3,67,141,0.3) 0%, rgba(0,169,234,0.3) 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, right top, color-stop(0%, rgba(3,67,141,0.3)), color-stop(100%, rgba(0,169,234,0.3))); /* Chrome,Safari4+ */
}
/*
img {
position: center;
top: 50%;
left: 50%;
margin-left: -(X/2)px;
margin-top: -(Y/2)px;
}
*/
#top {
top:0;
left:0;
right:0;
height: 110px;
padding-bottom: 10px;
position: fixed;
top: 0;
text-align:center;
}
#top div {
display:inline-block;
background:red;
max-width:750px;
}
#content .lav_porastes {
font-size:20pt;
text-align: left;
}
.image-cnt {
display:block;
margin:0 auto 110px;
width:146px;
height:195px;
}
/*
#lav-bg-intro {
background:url(lav-bg-intro.png) no-repeat 50% 50%;
width:100%;
height:100%;
position:absolute;
top:0;
left:0;
z-index:1;
}
*/
#header { padding:120px 0 0; }
@media screen and (max-width:650px) {
h1 { font-size:48px }
.lav {
font-size:25px;
line-height:40px;
width:90px;
height:40px;
}
}
</style>
</head>
<body>
<div id="container" >
<div id="top">
<div>top</div>
</div>
<div id="header"> header</div>
<div id="content">
<div id="dugme" > <a class="lav " href="http://lavpivo.rs/naslovna">ili jesi</a> <a class="lav " href="denied.xhtml">ili nisi</a> </div>
<h1>PUNOLETAN</h1>
</div>
<div id="bottom"></div>
<div id="footer"> </div>
</div>
</body>
</html>