html {
overflow-x:hidden;
vertical-align:top;
}
div {
margin:0;
}
<link rel="stylesheet" href="path-to-file/thickbox.css" type="text/css" media="screen" />
<center>
body {
background-color: #FFFFFF;
vertical-align:top;
align:center; 
font-family:Arial;
color:#ffffff;
line-height:20px;
margin:0px;
text-align:left;
font-style:normal;
height:100%;
background-image: url('http://www.professional-vector-art.net/images/background_pattern.gif');
}


.seitenueberschrift {
font-size:0px;
color:#FF6600;
font-weight:normal;
text-align:right;
padding-top:1px;
padding-left:800px;
font-family:Arial;
}

#header{
padding-top:0px;
align:center;
width:990px;
background:url(http://www.professional-vector-art.net/images/header_4.png); repeat-x; padding-top:36px;
}

#newsflash{height:100px;
font-family:Arial;
}

#top_menue {
padding-top:0px;
background-color:#333333;
border-top:0px solid #FFFFFF;
border-bottom:0px solid #FFFFFF;
font-size:12px;
font-style:bold;
font-family:Arial Black;
text-align:center;
align:center;
vertical-align:middle;
width:990px;
}

.my_banner {
width:990px;
padding-left:0px;
margin-left:0px;
height:216px;
padding-top:10px;
valign:center;
font-family:Arial;
background:url(../images/content_div_bg.png) repeat-x bottom;
}

#footer {
width:990px;
background-color:#333333;
background:url(../images/footer_div_bg_orange.png) repeat-x;
float:left;
height:153px;
padding-top:55px;
color:#333333;
font-size:11px;
font-color:#ffffff;
font-family:Arial;
margin:auto;
align:left;
vertical-align:center;
}

.seitenheader_div {
margin-left:875px;
margin-bottom:-30px;
width:115px; 
text-align:right;
height:150px;
}

.div_top{
padding-left:5px;
vertical-align:bottom;
text-align:left;
width:970px;
height:20px;
font-size:14px;
font-family:Arial;
}

.div_topmenue{
padding-top:13px;
padding-bottom:1px;
padding-left:15px;
vertical-align:middle;
text-align:left;
width:975px;
height:30px;
font-size:12px;
font-family:Arial Black;
}

.zentrier_mich {
align:center;
text-align:center;
background-color:#ffffff;
}

.div_contenttabelle{ 
width:990px;
min-height:800px;
align:left;
padding-top:0px;
font-size:11px;
font-style:normal;
font-family:Arial;
background-color: #FFFFFF;
float:left;
}

.div_contentheading {
background:url(../images/content_div_bg.png) repeat-x #FFFFFF top;
width:990px;
height:20px;
font-size:14px;
font-family:Arial;
}

.div_menue_links {
background-color: #FFFFFF;
width:170px;
min-height:800px;
float:left;
padding-top:10px;
padding-right:5px;
padding-left:5px;
text-align:left;
font-size:11px;
font-family:Arial;
line-height:20px;
}
.div_content {
background-color: #FFFFFF;
width:575px;
min-height:800px;
float:left;
text-align:left;
padding-top:10px;
padding-right:20px;
padding-left:20px;
font-size:11px;
font-family:Arial;
font-style:normal;
line-height:normal;
}

.div_menue_rechts {
background-color: #FFFFFF;
float:left;
width:190px;
min-height:800px;
padding-left:5px;
padding-top:10px;
font-size:11px;
font-style:bold;
font-family:Arial;
line-height:20px;
text-align:left;
white-space:wrap;
}


.div_newsflash {
color:#FFFFFF;

height:60px;
width:110px;
margin:auto;
padding-top:10px;
padding-bottom:10px;
text-align:left;
overflow:hidden;
font-family:Arial;
}
.div_newsflash h3{
color:#FFFFFF;
margin:0;
padding:0;
line-height:100%;
font-family:Arial;
}
.div_footer ul#mainlevel-nav li {
background:url(../images/bottom_menue_trennbalken.gif) right no-repeat;
font-family:Arial;
font-size:10px;
align:center;
background-color:#333333;
}

.div_user1, .div_user2  {
float:left;
margin-top:25px;
width:49%;
font-family:Arial;
}
.div_user1 {
padding-right:2%;
font-family:Arial;
}
.div_user1 h3,.div_user2 h3{
border-bottom:3px double #AAAAAA;
font-family:Arial;
}
.latestnews li a, .mostread  li a {
color:#333333;
font-weight:normal;
font-family:Arial;
}

h1,h2,h3,h4,h5,h6 {
margin:0;
padding:0;
font-family:Arial;
}
ul {
list-style:url(../images/pfeil_liste.gif);
margin:0;
padding:0;
margin-left:15px;
font-family:Arial;
}
a {
text-decoration:none;
font-weight:bold;
font-family:Arial;
}

ul li a, .pagenavcounter {
font-weight:bold;
}

ul#mainlevel-nav
{
margin:0;
margin-left:-10px;
padding:0;
display:inline;
font-weight: bold;
}
ul#mainlevel-nav li
{
list-style: none;
display:inline;
background:url(../images/top_menue_trennbalken.gif) right no-repeat;
padding:0px 10px 0px 10px;
}

ul#mainlevel-nav li a
{
color:#FFFFFF;
font-weight:bold;
}

ul#mainlevel-nav li a:hover
{
color:#ff6600;
font-weight:bold;
}

h3 {

margin-bottom:10px;
font-size:12px;
}
.contentheading, .blog_more div strong {

font-weight:bold;
}
.blog_more a {
font-weight:normal;
color:#333333;
}
.componentheading {

color:#333333;
padding-bottom:10px;
margin-bottom:10px;
font-size:14px;
font-family:Arial;
}

a.mainlevel:link,a.mainlevel:visited {
color:#ff6600;
display:block;
padding-left:13px;
min-height:21px;
background:url(../images/pfeil.gif) no-repeat;
font-weight:normal;
}

a.mainlevel:hover{
color:#ff6600;
display:block;
padding-left:13px;
min-height:21px;
background:url(../images/pfeil.gif) no-repeat;
font-weight:bold;
}

a.sublevel:link,a.sublevel:hover,a.sublevel:visited {
color:#ff6600;
display:block;
padding-left:10px;
margin-left:6px;
height:21px;
background:url(../images/pfeil.gif) no-repeat;
font-weight:normal;
}
#active_menu {
font-weight:bold;
}
.moduletable {
margin:0;
padding-bottom:10px;
}
.small {
color:#ff6600;
}
.createdate, .modifydate {
color:#999999;
}
#mod_login_username, #mod_login_password {
width:140px;
background-color:#FFFFFF;
border:1px solid #CCCCCC;
padding:2px;
color:#333333;
}
.button {
background-color:#CCCCCC;
border:1px solid #999999;
color:#333333;
margin-top:10px;
}
.inputbox {
background-color:#FFFFFF;
border:1px solid #CCCCCC;
padding:2px;
color:#333333;
}
.readon {
padding-left:5px;
}
.contenttoc {
margin:10px;
border:1px solid #CCCCCC;

}
.contenttoc td{
text-align:left;
padding-left:5px;
padding-right:5px;
}
.contenttoc th{
text-align:left;
background-color:#DEDEDE;
padding-left:5px;
padding-right:5px;
}
.label {
text-align:left;
}
.mosimage {
border:1px solid #CCCCCC;
margin:5px;
}
.mosimage_caption {
background-color:#DEDEDE;
}
.sectiontableentry2 label{
text-align:left;
}
.sectiontableentry2 {
background-color:#EFEFEF;
}
.sectiontableentry1 {
background-color:#DFDFDF;
}
.sectiontableentry1 td div a, .sectiontableentry2 td div a {
font-weight:bold;
border:none;
}
.div_bfree {
visibility:hidden;
overflow:hidden;
height:0px;
}

h3, .contentheading {
font-size:120%; line-height:20px;
}
.componentheading {
font-size:120%; line-height:30px;
}
img {
border:none;
}
.div_style_chooser {
vertical-align:middle;
text-align:right;
}
.div_style_chooser img {
vertical-align:middle;
}
.color_box {
background-color:#333333;
border-color:transparent;
color:#999999;
height:18px;
vertical-align:middle;
font-size:xx-small;

}
.color_box option{
padding:5px;
border-bottom:1px dotted #FFFFFF;
color:#FFFFFF;
}
</center>