How do I do this? (bottom colors)

Hello guys! I′m putting up a blog for my business (https://blog.videographia.com.br/) and its bottom is completely white, but I want to have my blog like these ones for example (https://www.calvinayrelife.com/ and https://www.blog.lifestagevideography.com/), or in other words, with the bottom in black but with a rectangle in the middle in white where the body text should be placed. Does anyone know how to do that? Is it very difficult? I′m attaching below the Stylesheet of my blog, so if anyone can show me what I have to do, I′d appreciate it a lot! Sorry for my English, it is not perfect yet. Thanks a lot!

/*
Theme Name: Cutline
Theme URI: https://pearsonified.com
Description: A squeaky clean, feature-rich theme for WordPress designed and coded by Chris Pearson.
Version: 1.2
Author: Chris Pearson
Author URI: https://pearsonified.com/
*/

body { background: #fff; color: #333; font: 62.5% Georgia, “Times New Roman”, Times, serif; text-align: center; }

* { padding: 0; margin: 0; }

/*—:[ global elements ]:—*/

a { color: #0060ff; text-decoration: underline; }

a:visited { color: #333; text-decoration: underline; }

a:hover { color: #df0000; text-decoration: underline; }

a img { border: none; }

blockquote { font-style: italic; font-family: Georgia, “Times New Roman”, Times, serif; color: #555; margin: 0 30px 1.5em 30px; padding: 0 0 0 10px; border-left: 1px solid #aaa; }

abbr, acronym { border-bottom: 1px dotted #aaa; text-transform: uppercase; cursor: help; }

code { color: #090; font-family: Courier, monospace; }

pre { margin: 0 0 1.5em 0; overflow: auto; font-size: 1.3em; clear: both; }

p.center { text-align: center !important; }

p.bottom { margin: 0 !important; }

p.unstyled { font-size: 1.4em; }

.flickr_blue { color: #007ae4; text-transform: lowercase; }

.flickr_pink { color: #ff2a96; text-transform: lowercase; }

.green { color: #090; }

.red { color: #f00; }

.orange { color: #f40; }

.purple { color: #909; }

/*—:[ headlines ]:—*/

h1, h2, h3 { font-weight: bold; font-family: Helvetica, Arial, sans-serif; color: #000; }

h1 { font-size: 3.6em; letter-spacing: -0.03em; }

#masthead h1 { padding: 0.4em 0 0.2em 0; border-top: 1px solid #ccc; text-align: center; clear: both; }

h1 a, h1 a:visited, h1 a:hover { color: #000; text-decoration: none; }

h2 { font-size: 2.0em; }

h2 a { color: #000; text-decoration: none; }

h2 a:visited { color: #555; text-decoration: none; }

h2 a:hover { color: #090; text-decoration: none; }

.posts h2 { margin: 0 0 0.1em 0; line-height: 1.2em; }

.pages h2, h2.page_header { margin: 0 0 0.75em 0; padding: 0 0 0.6em 0; background: url(‘images/hr_title_sep.gif’) 0 100% no-repeat; }

h2.archive_head { font-weight: bold !important; font-size: 1.4em !important; text-transform: uppercase !important; letter-spacing: normal !important; margin: 0 0 1.8em 0 !important; padding: 0.4em 2px !important; border-top: 3px solid #000 !important; background: url(‘images/hr_dot_black.gif’) 0 100% repeat-x !important; }

h3 { font-size: 1.0em; text-transform: uppercase; }

#masthead h3 { margin: 0 0 0.75em 0; font-weight: normal; font-size: 1.8em; text-transform: none; color: #888; text-align: center; }

.entry h3 { margin: 2.5em 0 0.5em 0; }

.entry h3.top { margin: 1.5em 0 0.5em 0 !important; }

h3.comments_headers { font-size: 1.4em; }

h4 { font: italic 1.2em Georgia, “Times New Roman”, Times, serif; color: #888; }

h4 a, h4 a:visited { color: #888; text-decoration: none; }

h4 a:hover { color: #888; text-decoration: underline; }

.posts h4 { margin: 0 0 1.25em 0; padding: 0 0 1.0em 0; background: url(‘images/hr_title_sep.gif’) 0 100% no-repeat; }

/*—:[ core layout elements ]:—*/

#container { width: 770px; margin: 15px auto 0 auto; }

#content_box { width: 770px; text-align: left; float: left; clear: both; }

#content { width: 500px; padding: 0 40px 0 0; float: left; }

#sidebar { width: 230px; float: left; }

#footer { width: 770px; padding: 1.2em 0 0 0; border-top: 2px solid #ccc; float: left; clear: both; }

/*—:[ header styles ]:—*/

#masthead { width: 770px; /*height: 100px; background: url(‘images/logo.gif’) no-repeat;*/ /* uncomment the height and background declarations here if you intend to use a graphic in the header instead of the h1 */ }

/* #masthead a { display: block; width: 770px; height: 100px; } */ /* uncomment this line if you use a graphic in the header – make sure the height of your header graphic is equal to the height declared in this line of code! */

ul#nav { list-style: none; width: 750px; padding: 0 10px; background: url(‘images/hr_dot_black.gif’) repeat-x; border-bottom: 3px solid #000; float: left; clear: both; }

ul#nav li { padding: 0.85em 40px 0.7em 0; font: bold 1.4em Helvetica, Arial, sans-serif; text-transform: uppercase; float: left; }

ul#nav li a, ul#nav li a:visited { color: #000; text-decoration: none; }

ul#nav li a:hover { color: #000; text-decoration: underline; }

ul#nav li a.current, ul#nav li a.current:visited, ul#nav li a.current:hover { color: #090; text-decoration: underline; }

ul#nav li.rss { padding: 0.85em 0 0.7em 0; float: right; }

ul#nav li.rss a { padding: 0 18px 0 0; background: url(‘images/icon_rss.gif’) 100% 50% no-repeat; }

#header_img { position: relative; margin: 0 0 3.0em 0; border-bottom: 1px solid #000; float: left; clear: both; }

#header_img img { display: block; } /* this is really just an IE 6 and 7 hack in disguise */

/*—:[ content styles ]:—*/

.entry { font-size: 1.4em; line-height: 1.65em; }

.entry blockquote { font-size: 1.0em; }

.entry blockquote.right { width: 200px; font-style: normal !important; font-size: 1.3em !important; margin: 0.3em 0 0.3em 15px !important; padding: 0.3em 0 !important; border: 3px double #aaa; border-width: 3px 0; text-align: center; float: right; }

.entry blockquote.left { width: 200px; font-style: normal !important; font-size: 1.3em !important; margin: 0.3em 15px 0.3em 0 !important; padding: 0.3em 0 !important; border: 3px double #aaa; border-width: 3px 0; text-align: center; float: left; }

.entry blockquote.right p, .entry blockquote.left p { margin: 0 !important; line-height: 1.4em !important; }

.entry p { margin: 0 0 1.5em 0; }

.entry ul, .entry ol { margin: 0 0 1.5em 40px; }

.entry ul { list-style-type: square; }

.entry li { margin: 0 0 0.5em 0; }

.entry ul li ul, .entry ul li ol, .entry ol li ul, .entry ol li ol { margin: 0.5em 0 0.5em 30px; }

.entry dl { margin: 0 0 1.5em 0; }

.entry dt { font-weight: bold; margin: 0 0 0.5em 0; }

.entry dd { margin: 0 0 1.5em 20px; }

.entry .ad { margin: 0 0 0.5em 15px; float: right; }

.entry .ad_left { margin: 0 15px 0.5em 0; float: left; }

.entry img { max-width: 490px; }

.entry img.left { padding: 3px; margin: 0.5em 15px 0.5em 0; border: 3px double #bbb; float: left; clear: left; }

.entry img.right { padding: 3px; margin: 0.5em 0 0.5em 15px; border: 3px double #bbb; float: right; clear: right; }

.entry img.center { display: block; padding: 3px; margin: 0 auto 1.5em auto; border: 3px double #bbb; float: none; clear: both; }

.entry img.off { padding: 0 !important; border: none !important; }

.entry img.stack { clear: none !important; }

.tagged { padding: 0.4em 0 0 0; background: url(‘images/hr_tag_sep.gif’) no-repeat; font-size: 1.2em; line-height: 1.6em; color: #888; clear: both; }

.tagged a, .tagged a:visited { padding: 0.25em; color: #333; text-decoration: none; }

.tagged a:hover { color: #fff; background: #333; text-decoration: none; }

.add_comment { display: block; padding: 0 0 0 20px; font-weight: bold; float: right; }

.navigation { width: 500px; font-size: 1.4em; float: left; }

.previous { padding: 0 20px 0 0; float: left; }

.next { float: right; }

.clear { width: 500px; height: 1px; margin: 0 0 5.0em 0; clear: both; }

.rule { background: url(‘images/hr_tag_sep.gif’) no-repeat; }

.flat { margin: 0 0 2.0em 0 !important; }

.whitespace { margin: 0 0 3.5em 0 !important; }

/*—:[ sidebar styles ]:—*/

ul.sidebar_list { list-style: none; }

ul.sidebar_list li.widget, ul.sidebar_list li.linkcat { width: 230px; margin: 0 0 2.5em 0; font-size: 1.3em; line-height: 1.4em; float: left; }

li.widget h2, li.linkcat h2 { font-weight: bold; font-size: 1.077em; text-transform: uppercase; letter-spacing: normal; margin: 0 0 0.8em 0; padding: 0.4em 2px; border-top: 3px solid #000; background: url(‘images/hr_dot_black.gif’) 0 100% repeat-x; }

li.widget p { margin: 0 0 1.5em 0; padding: 0 10px; }

li.widget ul, li.linkcat ul { list-style: square; margin: 0 0 0.5em 20px; }

li.widget ol, li.linkcat ol { margin: 0 0 0.5em 20px; }

li.widget li, li.linkcat li { margin: 0 0 0.7em 0; }

li.widget li a, li.widget li a:visited, li.linkcat li a, li.linkcat li a:visited { text-decoration: none; }

li.widget li a:hover, li.linkcat li a:hover { text-decoration: underline; }

li.widget li .recent_date { padding: 0 0 0 8px; font-weight: bold; color: #888; }

li.widget ul.flickr_stream { list-style: none; margin: 0; padding: 0 10px; }

li.widget ul.flickr_stream li { margin: 0; padding: 0 5px 5px 0; display: inline; }

li.widget ul.flickr_stream li a img { padding: 3px; }

li.widget ul.flickr_stream li a:hover img { background: #ff2a96; }

/*—< FlickrRSS styles for the widget only >—*/

li.widget_flickrrss { }

li.widget_flickrrss a img { margin: 0 5px 5px 0; padding: 3px; }

li.widget_flickrrss a:hover img { background: #ff2a96; }

/*—< Calendar widget styles >—*/

#calendar_wrap { font-size: 1.3em; }

/*—:[ footer styles ]:—*/

#footer p { margin: 0 0 0.923em 0; font-size: 1.3em; color: #888; text-align: right; }

#footer a, #footer a:visited { color: #888; text-decoration: none; }

#footer a:hover { color: #888; text-decoration: underline; }

/*—:[ comment styles ]:—*/

#comments { width: 500px; float: left; clear: both; }

ul#comment_list { list-style: none; margin: 0 0 4.0em 0; border-top: 1px solid #bbb; float: left; }

ul#comment_list li.comment { width: 500px; padding: 1.2em 0 0 0; border-bottom: 1px dotted #bbb; float: left; }

ul#comment_list li.trackback { width: 470px; padding: 1.2em 15px 0 15px; background: url(‘images/trackback_bg.gif’); }

.comment_meta { margin: 0 0 1.2em 0; }

.comment_num { padding: 0 15px 0 20px; font-weight: bold; font-size: 1.4em; float: right; }

.trackback .comment_num { padding: 0 0 0 20px; }

.comment_num a, .comment_num a:visited { color: #888; text-decoration: none; }

.comment_num a:hover { color: #df0000; text-decoration: none; }

.comment_meta strong { font-size: 1.6em; }

.comment_time { font: normal 1.1em Verdana, Helvetica, Arial, sans-serif; color: #888; }

.comment .entry { padding: 0 15px; }

.comment .entry p { margin: 0 0 1.0em 0; }

/*—:[ comment form styles ]:—*/

#comment_form { width: 500px; padding: 1.0em 0 0 0; float: left; }

#comment_form p { padding: 0.6em 0; }

#comment_form label { padding: 0 0 0 10px; font-size: 1.2em; }

#comment_form .text_input { width: 191px; padding: 3px; color: #444; font: normal 1.4em Georgia, “Times New Roman”, Times, serif; border-top: 2px solid #999; border-left: 2px solid #999; border-right: 1px solid #fff; border-bottom: 1px solid #fff; }

#comment_form .text_area { width: 321px !important; }

#comment_form .text_input:focus { border-top: 2px solid #666; border-left: 2px solid #666; border-right: 1px solid #ddd; border-bottom: 1px solid #ddd; }

#comment_form .form_submit { padding: 0.4em 4px; background: url(‘images/submit_bg.gif’); border: 3px double #999; border-top-color: #ccc; border-left-color: #ccc; font: bold 1.4em Georgia, “Times New Roman”, Times, serif; cursor: pointer; }

#comment_form p.subscribe-to-comments { font-size: 1.4em; }

#comment_form p.subscribe-to-comments label { font-size: 1.0em; }

/*—:[ search form styles ]:—*/

#search_form { }

#search_form .search_input { width: 221px; padding: 3px; color: #090; font: normal 1.0em Georgia, “Times New Roman”, Times, serif; border-top: 1px solid #999; border-left: 1px solid #999; border-right: 1px solid #f5f5f5; border-bottom: 1px solid #f5f5f5; }

li.widget .search_input { font-size: 1.1em !important; }

#search_form .search_input:focus { border-top: 1px solid #666; border-left: 1px solid #666; border-right: 1px solid #ddd; border-bottom: 1px solid #ddd; }