Post/Content seperate from Sidebar

hey there. n00b question again.

relating to this page for example https://thematadormusic.com/home/?page_id=25

I’ve managed to get the white background under the posts. Now i’d like that white background to be only down the side where the posts actually are ie i’d like the posts to be appearing in one white box and the side bar to be a seperate white box.

I’m doing this because there will eventually be background art.

here’s the entire style.css

/*
Theme Name: Satoshi v2.0
Theme URI: https://www.vooshthemes.com
Description: A Free Portfolio Theme Developed By Voosh Themes. Please look at the <a href="../wp-content/themes/satoshi/instructions/instructions.html">instructions</a> that are included with the file you downloaded <a href="../wp-content/themes/satoshi/instructions/instructions.html">(satoshi/instructions/instructions.html)</a> for details about how to configure this theme.
Author: Voosh Themes
Author URI: https://www.vooshthemes.com
*/

/* -- Color: Red - #9e1c1c -- */

@import "styles/reset.css";

/* -------------------- */
/* -- General Styles -- */
/* -------------------- */
#wrap { width: 960px; margin: 0 auto; }
body { font-family: tahoma; background-color: #000000; }
h1, h2, h3, h4, h5 { color: #222; }
h1 { font-size: 38px; margin: 0 0 30px 0; }
h2 { font-size: 34px; margin: 0 0 30px 0; }
h3 { font-size: 20px; margin: 30px 0 10px 0; }
h4 { font-size: 20px; margin: 30px 0 15px 0; }
h5 { font-size: 18px; margin: 30px 0 5px 0;}
p { font-size: 14px; line-height: 22px; margin: 0 0 15px 0; }
a { text-decoration: none; color: #9e1c1c; }
a:hover { color: #222; }

/* ------------ */
/* -- Header -- */
/* ------------ */
#header {   display: block;   margin-left: auto;   margin-right: auto; }
#header img {   display: block;   margin-left: auto;   margin-right: auto; padding: 40px 10px 0px 10px }
#header h1 { float: left; font-size: 80px; margin: 8px 0 0 0; }
#header h1 a { color: #222; }
#header img.description { float: right; margin: 50px 0 0 0; }

/* --------- */
/* -- Nav -- */
/* --------- */
#nav { float: left; margin: 30px -15px 0 0; border-top: 0px #eee solid; border-bottom: 0px #eee solid; width: 100%; background-color: #000000 }
.menu li { padding: 11px 0 10px 0; float: left; position: relative; }
.menu a { display: block; padding:  10px 35px 8px 0; margin: 0; color: #FFF; text-decoration: none; font-size: 18px; text-transform: uppercase; }
.menu .current a, .menu li:hover > a { color: #333333; }
.menu ul { background: #eee; display: none; margin: 0; padding: 0; width: 260px; position: absolute; top: 42px; left: 0px; border: solid 1px #ddd; }
.menu ul li { float: none; margin: 0; padding: 0; }
.menu ul li:hover a, .menu li:hover li a { color: #333333; }
.menu ul a:hover { background: #333333 !important; color: #fff !important; }
.menu li:hover > ul { display: block; }
.menu ul a { font-size: 16px; padding-left: 10px; text-transform: none; font-weight: normal; }
.menu ul ul { left: 250px; top: -3px; }
.menu li.current_page_item a { color: #fff; }
.menu .sub-menu li.current_page_item a { color: #cccccc; }

/* ---------------- */
/* -- Front Page -- */
/* ---------------- */
#headline { float: left; margin: 8px 0 0 0; padding:15px 0px 15px 0px; border-bottom: 0px #eee solid; width: 100%; }
#headline img { margin-left: 0px; }
#headline h2 { font-size: 50px; line-height: 55px; margin-bottom: 10px; color: #222 !important; }
#featured-section { clear: both; float: left; margin: 65px 0 0 0; padding-bottom: 60px; width: 100%; border-bottom: 2px #eee solid; }
#featured-section-image { float: left; background: url(images/featured-img-bg.png) no-repeat; width: 460px; height: 285px; }
#featured-section-image img { margin: 1px 0 0 1px; }
#featured-section-details { float: right; width: 450px; margin: -4px 0 0 0; }
#featured-section-details h2 { font-size: 30px; color: #222; margin-bottom: 20px; }
#featured-section-details p { font-size: 16px; line-height: 26px; }
.more-details-button { float: left; background: url(images/portfolio-button.png) no-repeat; width: 175px; height: 40px; text-indent: -9999px; margin: 0 0 0 -7px; }
.more-details-button:hover { float: left; background: url(images/portfolio-button-hover.png) no-repeat; }
#recent-work { clear: both; float: left; margin: 50px 0 0 0; padding-bottom: 50px; width: 100%; }
#recent-work h2 { font-size: 22px; color: #222; }
.recent-project { float: left; margin-left: 50px; width: 280px; margin-bottom: -50px; }
.recent-project img { border: 1px #ddd solid; }
.first { margin-left: 0; }
.recent-project h3 { font-size: 14px; font-weight: bold; color: #222; margin: 15px 0 5px 0; }
.recent-project p { font-size: 12px; }

/* ------------- */
/* -- Content -- */
/* ------------- */
#main { clear: both; float: left; margin: 50px 0px 0px 0px; width: 100%; background-color: #FFFFFF }
.title { margin-top: 10px; font-size: 16px; color: #000000; font-weight: bold; margin-bottom: 20px; text-align: center; }
#content { float: left; width: 500px; margin: 0px 10px 10px 10px}

/* --------------- */
/* -- Portfolio -- */
/* --------------- */
#portfolio-content { float: left; margin: 20px 0 0 0; }
.portfolio-item { float: left; margin-left: 56px; margin-bottom: 40px; }
.portfolio-item p { margin-bottom: 2px; }
.portfolio-item img { border: 1px #ddd solid; }
.first { margin-left: 0; }
#project-content { float: left; width: 450px; }
#project-image-large { float: right; }
#project-image-large img { border: 1px #ddd solid; }

/* ----------- */
/* -- Posts -- */
/* ----------- */
h3.post-meta { margin: -8px 0 20px 0; padding: 0; color: #888; font-size: 22px; }
.post { padding: 0 0 40px 0; }
.post-title { margin-top: 0; line-height: 28px; }
.post-title a, .archive-title { color: #222; font-size: 26px; }
.post-title a:hover, .archive-title a:hover { color: #9e1c1c; }
.more-link { display: block; margin: 10px 0 0 0; }
.archive-title a { margin-bottom: 30px; }
.post-navigation { font-size: 14px; }

/* ------------- */
/* -- Sidebar -- */
/* ------------- */
#sidebar { float: right; padding: 20px 0 5px 20px; background-color: #FFFFFF; border: 0px #ccc solid; width: 250px; }
.sidebar-title { margin-top: 0; }
.sidebar-contact-title { color: #000000; margin-bottom: 0; }

/* -------------- */
/* -- Comments -- */
/* -------------- */
#comments { clear: both; float: left; width: 480px; border-top: 2px #eee solid; margin-top: -20px; }
#comments h3 { padding-bottom: 0; }
.commentlist { margin: 25px 0 30px 0; }
.commentlist .comment { border: 1px solid #dddddd; padding: 15px; margin: 15px 0 0 0; background: url(images/input-bg.png) repeat-x; }
.commentlist .fn { color: #555555; font-size: 18px; margin-bottom: 15px; display: block; }
.commentlist .url { color: #9e1c1c; font-size: 18px; }
.commentlist .comment-meta { color: #888888; text-transform: uppercase; font-size: 10px; margin: -4px 0 0 0; }
.commentlist img { float: right; width: 25px; height: 25px; margin: 0 0 0 7px; padding: 2px; border: 1px solid #cccccc; }
.commentlist p { margin: 10px 0 10px 0; }
.commentlist .comment-reply-link { margin: 5px 0 0 -7px; display: block; }
.commentlist em { font-style: italic; font-size: 12px; }

/* respond form */
#respond h3 { margin-bottom: 10px; }
#respond .cancel-comment-reply { padding: 0 0 10px 0; }
#commentform { width: 480px; margin: 0 0 0 0; }
#commentform input { background: url(images/input-bg.png) repeat-x; float: left; color: #555555; width: 255px; font-size: 14px; padding: 12px 12px 12px 12px; margin-bottom: 20px; font-family: arial, sans-serif; border: 1px #ddd solid; }
#commentform textarea { background: url(images/input-bg.png) repeat-x; color: #555555; width: 456px; height: 238px;  margin: 5px 0 0 0; font-size: 14px; padding: 12px 12px; font-family: arial, sans-serif; border: 1px #ddd solid; line-height: 20px; }
#commentform .submit { background: url(images/comment-button.png) no-repeat; cursor: pointer; margin: 25px 0 0 -7px; color: #fff; width: 175px; height: 40px; border: none; padding: 8px 0; text-indent: -9999px; }
#commentform .submit:hover { background: url(images/comment-button-hover.png) no-repeat; color: #fff; }
#commentform label { float: left; padding: 8px 0 0 20px; text-transform: uppercase; color: #888888; font-size: 10px; }
#commentform .logged { margin: 0; }
.commentlist .comment-reply-link { margin: 10px 0 0 0; color: #9e1c1c; font-size: 12px; }
.commentlist .comment-reply-link:hover { color: #555; }

/* ------------------ */
/* -- Contact Form -- */
/* ------------------ */
#contact-form { width: 300px; }
#contact-form input { border: 1px #ddd solid; padding: 15px; width: 250px; margin: 0 0 15px 0; font-family: arial; color: #555; font-size: 12px; background: url(images/input-bg.png) repeat-x; }
#contact-form textarea { border: 1px #ddd solid; padding: 15px; width: 375px; margin: 0 0 15px 0; font-family: arial; color: #555; font-size: 12px; background: url(images/textarea-bg.png) repeat-x; line-height: 18px; }
#contact-form .submit { background: url(images/submit-button.png) no-repeat; cursor: pointer; margin: 0 0 0 -7px; color: #fff; width: 175px; height: 40px; border: none; padding: 8px 0; text-indent: -9999px; }
#contact-form .submit:hover { background: url(images/submit-button-hover.png) no-repeat; }
#response { border: 1px #ddd solid; padding: 15px; color: #9e1c1c; background-color: #eee; }
.hide { display: none; }

/* ------------ */
/* -- Footer -- */
/* ------------ */
#footer { clear: both; float: left; padding: 10px 0 50px 0; border-top: 2px #eee solid; margin: 50px 0 0 0; width: 100%; }
#footer p { font-size: 12px; color: #888;  }
#footer .copyright { float: left; }
#footer .design { float: right; }

thanks so much for your help