index.php idea for expantion and easy page adding

<?php
$button1 = $_GET['button1'];
$button2 = $_GET['button2'];
$button3 = $_GET['button3'];
$searchs = $_GET['searchs'];
$page = $_GET['page'];
session_start();
if($_SESSION) {
if($_SESSION['style']=='1') {
    echo '<link rel="stylesheet" href="css/colour1.css" type="text/css">';
    }
    elseif($_SESSION['style']=='2') {
    echo '<link rel="stylesheet" href="css/colour2.css" type="text/css">';
    }
    elseif($_SESSION['style']=='3') {
    echo '<link rel="stylesheet" href="css/colour3.css" type="text/css">';
    }
    else {
        echo '<link rel="stylesheet" href="css/colour1.css" type="text/css">';
        }
    }
    else {
        echo '<link rel="stylesheet" href="css/colour1.css" type="text/css">';
        }
        if($button1) {
        echo '<link rel="stylesheet" href="css/colour1.css" type="text/css">';
        $_SESSION['style'] = '1';
        }
        elseif($button2) {
echo '<link rel="stylesheet" href="css/colour2.css" type="text/css">';
        $_SESSION['style'] = '2';
        }
        elseif($button3) {
            echo '<link rel="stylesheet" href="css/colour3.css" type="text/css">';

        $_SESSION['style'] = '3';
        }
        else {

            }


 ?><html lang="en"><head>
<link rel="shortcut icon" href="http://30.media.tumblr.com/avatar_100d4932f131_16.png" />
 <meta charset="uft-8" />
 <meta keywords="pcwizz, 'pcwizz.net', linux, unix" />
<title>pcwizz.net | the home of pcwizz on the internet</title>
<link rel="stylesheet" href="css/common.css" type="text/css">
<script type="text/javascript">

  var _gaq = _gaq || [];
  _gaq.push(['_setAccount', 'UA-16575667-4']);
  _gaq.push(['_setDomainName', '.pcwizz.net']);
  _gaq.push(['_trackPageview']);

  (function() {
    var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
    ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
    var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
  })();

</script>
</head><form class="asside" id="style" method="GET" action="index.php">
<input type="submit" name="button1" value="style 1" size="8" />
<input type="submit" name="button2" value="style 2" size="8" />
<input type="submit" name="button3" value="style 3" size="8" /></form><br><br><br><body><span class="header">

<br>
<div ><nav id="main-navigation">
       <ul id="main_nav">
                <li><a href="index.php">home</a></li>
                <li><a href="index.php?page=news">tech news</a></li>
        <li><a href="#">How To?</a><ul>
        <li><a href="index.php?page=howtocodein">how to code in</a></li>
                </ul></li>
                <li><a href="index.php?page=blog">blog</a></li>
                <li><a href="http://www.youtube.com/pcwizzshow">youtube</a></li>
                <li><a href="index.php?page=minecraft">minecraft</a></li>
                <li><a href="#">social</a><ul>
                <li><a href="http://www.facebook.com/pages/pcwizz/339557311428">facebook</a></li>
                <li><a href="http://twitter.com/#!/pcwizz">twitter</a></li>
                <li><a href="http://pcwizz.tumblr.com">tumblr</a></li>
                </ul></li>
        </nav></div><font size="5">


</font></span>
<div id="logo"><img src="pcwizzfav.jpg" alt="" ></div>
    <form class="search" action="index.php"  method="GET">
<input type="text" name="search" >
<select name="searchs" size="3">
<option value="news" title="news">news</option>
<option value="blog" title="blog">blog</option>
<option value="pages" title="pages">pages</option>
</select>
<input type="submit" name="submit" value="search">
</form>
<span class="body">
<section><artical><hgroup>
<?php
$button = $_GET['submit'];
$run = mysql_query("SELECT * FROM  `pages` WHERE `ref` LIKE '%$page%'");
while($runrows = mysql_fetch_assoc($run)) {
$code = $runrows['code'];
echo = $code;

}

 ?><p>tweet this page<br><a href='https://twitter.com/share' class='twitter-share-button' data-url="http://pcwizz.net/index.php?page=<? echo $page; ?>" data-text='i think you might like this very much read this page <? echo $page; ?>' data-via='pcwizz' data-hashtags='pcwizz'>Tweet</a>
<script>!function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src='//platform.twitter.com/widgets.js';fjs.parentNode.insertBefore(js,fjs);}}(document,'script','twitter-wjs');</script></artical></hgroup></section>

 <footer></span>


</footer>
</body>
</span>


</html>