How to echo html elements, inline

How to echo html elements, inline

every second item needs to be on right side of the page, but inline with
first item, so it would create 2x2 type grid of both echoed items.
I added some CSS like this .container{float:left; width:50%;} but it
didn't work.
if ($file6 % 2 == 1)
{
echo '<div id="container">
<div id="thumbnail">
<a href="/images/tirgus/'. $file .'"
title="'.cleanString($file).'" class="thickbox"><img
src="/images/tirgus/thumbs/'.$row['id'].'.jpeg" width="141"
height="74" alt="image" /></a>
</div>
<br>
<div id="info1">_{' .cleanString($file2).'}</div>
<br>
<div id="info2">_{Telefons: ' .cleanString($file3).
'}<br>_{email: '.cleanString($file4).'}</div><br>
<div id="info3">_Iepostoja: ' .cleanString($file5).
'</div><br>
</div><widgets><customization><css> <link rel="stylesheet"
href="template_faili/gallery.css"></css></customization></widgets>';
}
else if ($file6 % 2 == 0) {
echo '<div id="container2">
<div id="thumbnail2">
<a href="/images/tirgus/'. $file .'"
title="'.cleanString($file).'" class="thickbox"><img
src="/images/tirgus/thumbs/'.$row['id'].'.jpeg" width="141"
height="74" alt="image" /></a>
</div>
<br>
<div id="info1">_{' .cleanString($file2).'}</div>
<br>
<div id="info2">_{Telefons: ' .cleanString($file3).
'}<br>_{email: '.cleanString($file4).'}</div><br>
<div id="info3">_Iepostoja: ' .cleanString($file5).
'</div><br>
</div><widgets><customization><css> <link rel="stylesheet"
href="template_faili/gallery.css"></css></customization></widgets>';
}
}