Background problem when viewed on tablet

Thanks for the reply noahjonah, link for blog is

Here

My knowledge is limited so you might need to to speak in more simpler terms.

OK, here is the stylesheet code. Perhaps someone can spot something amiss?

@charset "utf-8";
/*
Theme Name: Moonbeams
Theme URI: http://www.jusanya.com/moonbeams
Description: Moonbeams theme for WordPress is stylish, simple and customizable. You can change background image/color and header image from WordPress admin panel. SEO optimized, multiple widget-ready placement, custom menu, threaded-comments and valid XHTML 1.0 Transitional. For WordPress version 3.0+
Version: 1.25
Author: Maruyama Kiyotaka
Author URI: http://www.maruyamakiyotaka.com
Tags: black, one-column, two-columns, three-columns, right-sidebar, fixed-width, custom-background, custom-header, custom-menu, translation-ready
License: GNU General Public License v2.0
License URI: http://www.gnu.org/licenses/gpl-2.0.html
*/

/*
Copyright (c) 2010, Yahoo! Inc. All rights reserved.
Code licensed under the BSD License:
http://developer.yahoo.com/yui/license.html
version: 2.8.2r1

Font-size Adjustment
10px = 77%HEADER
11px = 85%
12px = 93%
13px = 100%
14px = 108%
15px = 116%
16px = 123.1%
17px = 131%
18px = 138.5%
19px = 146.5%
20px = 153.9%
21px = 161.6%
22px = 167%
23px = 174%
24px = 182%
25px = 189%
26px = 197%
*/
body{font:13px/1.231 arial,helvetica,clean,sans-serif;*font-size:small;*font:x-small;}select,input,button,textarea,button{font:99% arial,helvetica,clean,sans-serif;}table{font-size:inherit;font:100%;}pre,code,kbd,samp,tt{font-family:monospace;*font-size:108%;line-height:100%;}

body,div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre,form,fieldset,input,textarea,p,blockquote,th,td {
	margin:0;
	padding:0;
}
table {
	border-collapse:collapse;
	border-spacing:0;
}
fieldset,img {
	border:0;
}
ol,ul {
	list-style:none;
}
caption,th {
	text-align:left;
}
h1,h2,h3,h4,h5,h6 {
	font-size:100%;
}

/* background */
html {
background:#000 url('images/background.jpg') fixed no-repeat center top;
color:#FFFFFF;
text-align:center;
}

/* font */
strong {
font-weight:bold;
}

a {
color:#ffff66;
}

a:hover {
color:#FFFFFF;
}

#copyright {
text-align:right;
color:#FFFFFF;
}

#copyright a {
color:#FFFFFF;
text-decoration:none;
}

#copyright a:hover {
color:#FFFFFF;
}

/* hx */
h1,h2,h3,h4,h5,h6 {
margin:10px 0 0.5em 0;
font-weight:normal;
}

h1 {
font-size:138.5%; color:#ffff66;
margin-bottom:1em;
}

h2 {
font-size:116%; color:#ffff66;
}

h3 {
font-size:108%; color:#ffff66;
}

h5 {
font-weight:normal;
font-size:93%;
}

h6 {
font-weight:normal;
font-size:85%;
}

/* p */
p {
margin-bottom:1em;
line-height:1.5em;
}

/* ul, ol, dl */
ul ul,ul ol,ol ul,ol ol {
margin: 0;
padding: 0 0 0 1em;
}

ul {
padding-left:1.5em;
list-style-type:disc;
}

ol {
padding-left:2.5em;
list-style-type:decimal;
}

dt {
line-height:2em;
font-weight: bold;
margin-top: 1em;
border-bottom: dotted 1px #C0C0C0;
}

dd {
padding-left: 1em;
margin-top: 0.5em;
}

/* image */
.content img {
height: auto;
max-width:580px;
}

.postContent img {
margin: 10px;
border: 3px solid #CCC;
max-width: 580px;
width: expression(this.width > 500 ? 500: true);
}

.content div {
height: auto;
max-width:580px;
}

.content .attachment img {
max-width:900px;
}

a img {
border:none;
}

/* header */
#header {
position:relative;
width:1080px;
height:200px;
margin:0 auto;
text-align:left;
}

#info {
position:relative;
height:300px;
padding-left:10px;
padding-top:20px;
}

#info .sitename {
font-size:138.5%;
}

#info .sitename a {
text-decoration:none;
}

#info .sitedesc {
font-size:93%;
margin-left:2em;
}

/* wrapper */
#wrap {
position:relative;
width:1080px;
margin:15px auto;
text-align:left;
z-index:1;
}

/* columns */
#main {
position:relative;
width:580px;
float:left;
}

.content {
position:relative;
margin-bottom:10px;
}

.maincolumn,
.sidecolumn {
margin:0 auto 30px auto;
}

.maincolumn {
width:700px;
}

.sidecolumn {
width:480px;
font-size:93%;
}

.post {
padding-bottom:10px;
margin-bottom:15px;
border-bottom:solid 1px #222;
}

/* sidebar */
#left {
position:relative;
float:left;
width:60px;
margin-left:10px;
}

#right {
position:relative;
float:right;
width:350px;
}

/* footer menu */
#footer_left {
position:relative;
width:238px;
float:left;
}

#footer_right {
position:relative;
width:238px;
float:right;
}

/* footer */
#footer {
position:relative;
clear:both;
width:1080px;
height:300px;
margin:0 auto;
text-align:left;
line-height:130%;
font-size:93%;
}

#copyright {
position:relative;
margin:10px 0 0 0;
}

/* search */
#search {
margin:5px;
}

#search #s {
background:#fff url('images/search.png') 0 center no-repeat;
font-size:.9em;
padding:3px 0 3px 20px;
width:250px;
}

#search input {
border:1px solid #ccc;
}

.search-excerpt {
margin:0;
}

/* calender */
table#wp-calendar {
width:100%;
}

table#wp-calendar td,
table#wp-calendar th {
padding:1px;
text-align:center;
}

/* navigation */
.navigation {
margin-bottom:2em;
}

.menu-container {
position:relative;
width:1080px;
margin:15px auto;
text-align:left;
z-index:9999;
}

/* page navigation */
.nav-previous {
float:left;
}

.nav-next {
float:right;
}

/* meta */
.contentmeta {
margin-bottom:15px;
}

.contentmeta ul {
list-style:none;
margin:0;
padding:0;
}

/* comments */
ol.commentlist {
margin-bottom:15px;
}

ol.commentlist,
ol.commentlist ul {
list-style:none;
padding:0;
}

ol.commentlist li {
border-top:solid 1px #222;
border-left:solid 1px #222;
padding:10px 0 0 10px;
}

ol.commentlist li li {
}

ol.commentlist li.bypostauthor cite {
font-weight:bold;
}

ol.commentlist li.byuser {
}

.comment,
.trackback,
.pingback {
margin-top:10px;
}

.avatar {
float:left;
margin-right:1em;
}

.reply {
text-align:right;
}

.comment-form-author,
.comment-form-email,
.comment-form-url,
.comment-form-comment {
margin:3px;
}

/* comment form */
#commentform p.logged-in-as,
#commentform p.comment-notes,
#commentform p.form-allowed-tags {
font-size:85%;
}

.required {
color:#cc0000;
}

#commentform input#author,
#commentform input#email,
#commentform input#url {
float:left;
width:250px;
margin-right:1em;
}

#commentform textarea {
width:100%;
height:8em;
}

#commentform p.comment-form-comment label {
display:none;
}

/* gallery */
.gallery dl {
margin:0;
overflow:hidden;
}

.gallery dt {
font-weight: normal;
border-bottom: none;
}

.gallery dd {
padding: 0;
}

.gallery img {
border:none !important;
}

/* feed */
.feed {
margin-left:3px;
padding:0 0 0 15px;
background:url('images/feed_mini.png') no-repeat 0 50%;
}

/* wp */
.aligncenter {
display:block;
margin:0 auto;
}

.alignleft {
float:left;
margin-right:15px;
}

.alignright {
float:right;
margin-left:15px;
}

.alignnone {
display:block;
}

.wp-caption,
.gallery-caption {
text-align:center;
}

.wp-caption img {
border:none;
margin:0;
padding:0;
}

.wp-caption p.wp-caption-text {
font-size:85%;
margin:0;
padding:3px;
}

.attachment-post-thumbnail {
float:left;
margin-right:10px;
}

.sticky {
border:solid 1px #C0C0C0;
padding:0 15px;
margin-bottom:30px;
}

/* author */
#entry-author-info {
margin:20px 0 30px 0;
}

/* blockquote, pre */
blockquote {
margin:10px;
padding:0 10px;
border-left:solid 3px #C0C0C0;
}

pre {
font-family: "Courier New",Courier,monospace;
border: inset 1px #000;
line-height: 120%;
margin: 1em 0 0 0;
padding: 0.99em;
}

/* table */
.content table {
border: 1px #C0C0C0 solid;
border-collapse:collapse;
border-spacing:0;
}

.content table th {
padding: 5px;
border: #C0C0C0 solid;
border-width: 0 0 1px 1px;
font-weight: normal;
}

.content table td {
padding: 5px;
border: #C0C0C0 solid;
border-width: 0 0 1px 1px;
}

caption,th {
text-align:center;
}

/* clearfix */
.clearfix:after {
  content: ".";
  display: block;
  clear: both;
  height: 0;
  visibility: hidden;
}

.form-allowed-tags { display: none; }

.clearfix {
  min-height: 1px;
}

* html .clearfix {
  height: 1px;
  /*¥*//*/
  height: auto;
  overflow: hidden;
  /**/
}

Thankyou WPyogi for your help here, I am confused with how I go about find where all the errors are.
For instance, the first one on the list reads

Error Line 8, Column 91: NET-enabling start-tag not immediately followed by null end-tag

…shortcut icon” href=”http://trinder.org/blog/favicon.ico” type=”image/x-icon” /

✉

This error may occur when there is a mistake in how a self-closing tag is closed, e.g ‘…/ >’. The proper syntax is ‘… />’ (note the position of the space).

Where do I find line 8 column 81?

Resolved. Changed the theme.