HTML Header and border Issues - html

Question

Issues I'm having:
When I decided to take the borders off the css the header area gets smaller (which i do not want to happen). - I want to take off the border lines without moving anything around.
When I place an image into the header(it stretches and does not display correctly). Also over the image, I want to place a text is that possible?
Also, if you go onto the menu page, you will see that the thumbnails are not aligned, why is that?
Here is the website: http://younani.com/finalsite/finalindex.html
Here is my css:
#header {
text-align: center;
background: url('bg1.gif');
}
#container {
width: 960px;
margin: 0 auto;
background-color: #FAFAFA;
color: #003300;
font-family: Arial, Helvetica, sans-serif;
background-image: url('backgroundflower5.jpg');
background-repeat: no-repeat;
background-position: center;
background-size: cover;
}
#h2 {
text-align: center;
}
#container {
width: 960px;
margin: 0 auto;
}
#container div {
border: 1px solid;
}
#center2 {
float: left;
margin: 10px 0 10px 20px;
min-width: 200px;
width: 494px;
border-radius: 8px;
}
#left,#center,#right {
float: left;
margin: 10px 0 10px 20px;
min-width: 200px;
}
#center {
font-family: Josefin Slab;
background-color: #FFFFFF;
width: 494px;
border-radius: 8px;
text-align: center;
}
.clear {
clear: both;
}
#right {
font-family: Josefin Slab;
font-weight: bold;
border-radius: 8px;
background-color: #FFFFFF;
}
#left a {
font-family: Arial, Helvetica, sans-serif;
font-size: 14px;
color: #ffffff;
display: block;
padding: 10px 20px;
background: -moz-linear-gradient(
top,
#ffffff 0%,
#2a07ed);
background: -webkit-gradient(
linear, left top, left bottom,
from(#ffffff),
to(#2a07ed));
-moz-border-radius: 30px;
-webkit-border-radius: 30px;
border-radius: 30px;
border: 3px solid #ffffff;
-moz-box-shadow: 0px 3px 11px rgba(000,000,000,0.5),
inset 0px 0px 1px rgba(026,020,219,1);
-webkit-box-shadow: 0px 3px 11px rgba(000,000,000,0.5),
inset 0px 0px 1px rgba(026,020,219,1);
box-shadow: 0px 3px 11px rgba(000,000,000,0.5),
inset 0px 0px 1px rgba(026,020,219,1);
text-shadow: 0px -1px 0px rgba(000,000,000,0.2),
0px 1px 0px rgba(255,255,255,0.3);
}
#left a:link {
background-color: #E6E6E6;
}
#left a:visited {
background-color: #E6E6E6;
}
#left a:hover {
border: 3px inset #333333;
}
#left ul {
list-style-type: none;
margin: 0;
padding-left: 0;
}
#footer {
text-align: center;
font-family: Audimat;
clear: both;
width: 38%;
border-radius: 8px;
background-color: white;
text-align: center;
margin-right: auto;
margin-left: auto;
}
Here is the relevant HTML of my home page:
<div id="container" class="clearfix">
<!-- Header -->
<div id="header">
<h1>Younani Flowers</h1>
</div>
<!-- Left Column -->
<div id="left">
<ul>
<li>Home</li>
<li>Menu</li>
<li>Occasions</li>
<li>About Us</li>
<li>Contact Us</li>
</ul>
</div>
<!-- Center Column -->
<div id="center">
HELLLLLO :D :D
</div>
<!-- Right Column -->
<div id="right">
<p><span style="text-decoration: underline;"><strong>Birth Month Flowers</strong></span></p>
<p>January Carnation</p>
<p>February Iris</p>
<p>March Daffodil</p>
<p>April Daisy</p>
<p>May Lily</p>
<p>June Rose</p>
<p>July Delphinium</p>
<p>August Dahlia</p>
<p>September Aster</p>
<p>October Calendula</p>
<p>November Chrysanthe</p>
<p>December Poinsettia</p>
</div>
<!-- Footer -->
<div id="footer" class="clear">
<div class="nav">
<b>
Home
Menu
Occasions
About Us
Contact Us
</b>
</div>
</div>
</div>
<!-- #container -->

Answer 1

<div id="header" style="float: left; width: 100%;">
<h1>Younani Flowers</h1>
</div>
------or-----
Apply clearfix
<div id="header" class="clearfix">
<h1>Younani Flowers</h1>
</div>
http://www.webtoolkit.info/css-clearfix.html