Sidebar drops to bottom

Can anyone tell me why the sidebar drops to bottom when you navigate from the index/frontpage to any other page on the blog? I’ve played with the CSS forever and can’t figure out what is out of whack. Thanks in advance!

Here’s the site:
https://paintingchef.com/

And the CSS:
body {background: #FFF;
font: 12px “Tahoma”, Verdana, Geneva, Arial, Helvetica, sans-serif;}

a, a:visited, a:link {color: #900;}

a:hover {text-decoration: none; background: #CF9;}

a:active {background: #CFF99;}

input, textarea {background: #FFF;}

input:focus, textarea:focus {background: #FFF;}

/*wrapper*/
#wrapper {
margin: 0px auto;
width: 650px;
background: #900 url(images/bg_main.jpg) repeat-y;}

/*header*/
#head {
height: 273px;
width: 650px;
background: url(images/bg_head.gif);}

#head div#blog_title {
color: #9F6;
position: relative;
top: 0px;
left: 20px;
font: 2em “Trebuchet MS”, “Tahoma”, Verdana, Geneva, Arial, Helvetica, sans-serif;}

#head div#blog_title a {color: #9F6; text-decoration: none;}

#head div#blog_title a:hover {background: transparent;}

/* main elements*/
#main {
width: 420px;
background: transparent;}

#main h1, #main h2 {
color: #900;
font: normal 1.5em “Trebuchet MS”, “Tahoma”, Verdana, Geneva, Arial, Helvetica, sans-serif;}

#main h2 {
font-size: 1.5em;}

#main h1 a, #main h2 a {
text-decoration: none;}

#main p, #main div.navigation, #main ul, #main div.post, #main div.date, #main #searchform {
margin: 5px 15px 5px 15px;
font size: 2.0em ;
font weight: normal;
text-align: justify;
line-height: 1.4em;
padding-left: 15px;
padding-right: 10px;}

#main div.date {
margin-bottom: 0;}

/* sidebar */

#sidebar {
float: right;
top: 300px;
width: 220px;
margin: 20px 0 15px 0 0
padding: 25px 0 14px 20px;
list-style: none;
font: normal 1em “Trebuchet MS”, “Tahoma”, Verdana, Geneva, Arial, Helvetica, sans-serif;
color: #900;
background: url(images/bg_sidebar_main.jpg) repeat-y;}

#sidebar h4 {
margin: 0;
padding: 25px 0 14px 20px;
background: transparent url(images/bg_sidebar_head.jpg) no-repeat;
font: normal 1.3em “Trebuchet MS”, “Tahoma”, Verdana, Geneva, Arial, Helvetica, sans-serif;}

#sidebar ul {
margin: 0;
padding: 0 0 40px 0;
list-style: none;
background: url(images/bg_sidebar_footer.jpg) no-repeat bottom left;}

#sidebar ul li {
background: transparent;
padding: 0 0 3px 30px;}

/* footer */
#footer {
width: 650px;
clear: both;
padding-top: 50px;
padding-bottom: 30px;
color: #9F6;
background: #900 url(images/bg_footer.jpg) no-repeat;}

#footer p {
margin: 0 50px;
font-size: 0.8em;
line-height: 1.5em;}

#footer a, #footer a:link, #footer a:visited, #footer a:hover, #footer a:active {
color: #9F6;
background: transparent;}

/* comments*/
#commentform {
margin-bottom: 40px;}

#commentform input, #commentform textarea {
width: 180px;
margin:5px 5px 5px 5px;
padding: 3px;
color: #FFF;
font: 1.0em/1.4em “Tahoma”, Verdana, Geneva, Arial, Helvetica, sans-serif;}

#commentform input[type=submit] {
width: 20em;
float: left;}

#commentform label {
display: block;
padding-bottom: 3px;}

#commentlist {
margin:5px 5px 5px 5px;
padding: 1px;
line-height: 1.4em;
list-style-type: none;}

#commentlist li {
padding: 1px;
margin:5px 5px 5px 5px;}

#commentlist li p {
padding: 1px;
margin:5px 5px 5px 5px;}

#commentlist cite {
display: block;
padding: 3px;
font-style: normal;
margin:5px 5px 5px 5px;;
font-weight: bold;
margin-bottom: 3px;
background: #CCFF99;}

#searchform input[type=submit] {
margin-top: 2px;}

#comments_popup {
margin:5px 5px 5px 5px;
padding: 1px;
background: #CCFF99;
font: 12px “Tahoma”, Verdana, Geneva, Arial, Helvetica, sans-serif;}

#comments_popup h1#header {
margin:5px 5px 5px 5px;
padding: 5px;
color: #360;
background: #CCFF99;
font: 2.5em “Trebuchet MS”, “Tahoma”, Verdana, Geneva, Arial, Helvetica, sans-serif;}

#comments_popup h1#header a {
color: #9F6;
text-decoration: none;}

#comments_popup h1#header a:hover {
background: transparent;}

#comments_popup #main {
width: 100%;
}
#comments_popup #main p, #comments_popup #main h2, #comments_popup #main #commentlist #postcomments #comments h2{
margin:5px 5px 5px 5px;
padding: 0;}

#comments_popup #footer {
width: 100%;
padding: 5px 0;
background: #900 none;