Buttons Nebeneinander

#extraDiv1 {display: none;}
#extraDiv2 {display: none;}
#extraDiv3 {display: none;}
#extraDiv4 {display: none;}
#extraDiv5 {display: none;}
#extraDiv6 {display: none;}
#pre_header {display: none;}
#post_header {display: none;}
#pre_content {display: none;}
#nav_heading{display: none;}
div.header{display: none;}
h1#title{display: none;}
h2#title span {display: none;}

a{
color:#4A9AF6;
text-decoration: none;
font-size:13px;}

a:hover {
color: #4A9AF6;
font-size: 13px;
text-decoration: none;}

a:link {
color: #4A9AF6;
font-size: 13px;
text-decoration: none;}

a:active {
color: #4A9AF6;
font-size: 13px;
text-decoration: none;}

a:visited {
color: #4A9AF6;
font-size: 13px;
text-decoration: none;}

body {
background-color:#000000;}

*{ padding: 0; margin: 0; }

#Mein_Bild {
margin: 0 auto;
width: 980px;
height:500px;
background-image:url(HIER DEINE BILD-URL);}

#header_container {
position: absolute;
left: 38%;
top: 25px;
margin-left:-490px;
width: 1280px;
height:250px;
background-color:;
background-image:url(http://img.webme.com/pic/s/siteof-k/head.png);
color:#FFFFFF;
font-size:13px;
border: 0px solid #FFFFFF;}

#content {
position: absolute;
left: 39%;
top: 290px;
margin-left:-320px;
width: 915px;
height: 310px;
padding:10px;
color: #F2F2F2;
font-size:13px;
background-color:#343434;
background-image:url(http://img.webme.com/pic/s/siteof-k/content.png);
border: 0px solid #FFFFFF;
overflow:auto;}

#nav_container{
position:absolute ;
left: 82%;
top:250px;
margin-left: -490px;
width: 360px;
height:500px;
border:0px solid red;
overflow:auto;}


ul#nav{
width: 150px;
padding: 0px;
margin: 0px;}

li.nav_element{
list-style-type: none;
position: relative;
padding:5px;
width: 115px;}

li.nav_element a{
display: block;
width: 50px;
padding:4px;
font-weight: bold;
text-decoration: none;
text-align: left;
color:red;
background-color:black;
background-image:url(HIER BUTTON-URL_1);
border: 2px solid #000000;}

li.nav_element a:hover{
color: white;
background-color black;
background-image:url(HIER BUTTON-URL_2);}