記事フォントサイズの変更ができないのですが、教えてください。

Sightというテーマのテンプレートを使用しています。
記事のフォントサイズやが小さく、変更したいのですが、良く聞く変更方法ができないのですが、どの様にすれば良いでしょうか？素人なので余り難しいことが分かりません。
念のため、スタイルシートは以下の様になっています。
同様にフォントそのものも変更したいのですが・・・。

/*
Theme Name: Sight
Author URI: http://www.wpshower.com
Description: Sight is a powerful WordPress theme, best suited for Magazines and Blogs. The theme was designed in modern minimalistic style with Golden Grid usage.
Author: WPSHOWER
Version: 1.0
License: GNU/GPL Version 2 or later. http://www.gnu.org/licenses/gpl.html
Copyright: (c) 2010 WPSHOWER
*/

/*** Reset ***/

html,body,div,span,applet,object,iframe,h1,h2,h3,h4,h5,h6,p,blockquote,pre,a,abbr,acronym,address,big,cite,code,del,dfn,em,font,img,ins,kbd,q,s,samp,small,strike,strong,sub,sup,tt,var,b,u,i,center,dl,dt,dd,ol,ul,li,fieldset,form,label,legend,table,caption,tbody,tfoot,thead,tr,th,td{margin:0;padding:0;border:0;outline:0;font-size:100%;vertical-align:baseline;background:transparent;}
body{line-height:1;text-align:left;}
ol,ul{list-style:none;}
blockquote,q{quotes:none;}
blockquote:before,blockquote:after,q:before,q:after{content:”;content:none;}
:focus {outline:0;}
ins{text-decoration:none;}
del{text-decoration:line-through;}
table{border-collapse:collapse;border-spacing:0;}

/*** Main ***/

body {font: 100% Georgia, Geneva, “Times New Roman”, times; background: #27292a url(“images/line.png”) 50% 0 no-repeat; padding: 24px 0;}
.clear:after {content: “.”; display: block; height: 0; clear: both; visibility: hidden;}
.left {float: left;}
.right {float: right;}

.wrapper {width: 975px; background: #fff; margin: 0 auto;}
#container {padding: 30px 0 45px;}

/*** Header ***/

.header {height: 158px; overflow: hidden; padding-right: 30px;}

.logo {width: 290px; height: 128px; padding: 18px 0 12px 30px; overflow: hidden; float: left;}
.logo img {max-height: 128px; max-width: 290px;}

.site-description {width: 290px; height: 111px; padding: 35px 10px 0; float: left; overflow: hidden;}
.site-description .textwidget {font-size: 11px; color: #656363; line-height: 1.4;}

.menu {width: 100px; padding-right: 30px; float: right;}
.menu ul {margin-top: 35px;}
.menu li {font-size: 11px; text-transform: uppercase; margin: 6px 0;}
.menu a {color: #000; text-decoration: none;}
.menu a:hover {text-decoration: underline;}

.search {width: 145px; margin-top: 28px; float: right;}
.search fieldset {width: 145px; height: 31px; background: #dadada;}
.search input {width: 105px; border: none; background: none; padding: 8px; color: #fff; font: 11px Georgia, Geneva, “Times New Roman”, times; text-transform: uppercase; vertical-align: middle;}
.search button {width: 16px; height: 16px; background: url(“images/search.png”) 50% 50% no-repeat; cursor: pointer; border: none; vertical-align: middle;}

/*** Navigation ***/

.nav {border-top: 1px solid #d9d9d9;}
.dd {height: 48px;}
.dd li {float: left; display: block; border-left: 1px solid #d9d9d9; text-align: center; font-size: 13px; text-transform: uppercase;}
.dd li a {color: #000; text-decoration: none; display: block; padding-top: 18px; margin: 0 14px; white-space: nowrap;}
.dd li a:hover {text-decoration: underline;}
.dd li ul {position: absolute; padding: 8px 0 10px; visibility: hidden; background: #000; z-index: 100;}
.dd li ul li {float: none; border: none; font-size: 11px; text-align: left; margin: 5px 0; padding: 0 8px;}
.dd li ul li a {color: #fff; display: inline; margin: 0 !important; white-space: normal; padding-top: 0;}
.dd li.dd_hover {background: #000;}
a.dd_hover:hover {text-decoration: none !important;}
.submenu a:hover {text-decoration: underline;}
.dd li.parent a {margin: 0 8px; padding-right: 12px; background: url(“images/dd.png”) 100% 24px no-repeat;}
.dd li.parent a.dd_hover {color: #fff; background: url(“images/dd_hover.png”) 100% 24px no-repeat; margin: 0 8px; padding-right: 12px; border-bottom: 1px solid #fff; padding-bottom: 10px;}

/*** Slideshow ***/

#slideshow, .slideshow {height: 290px; width: 975px; overflow: hidden; position: relative;}
.slide {height: 290px; width: 975px; background: #ffea97;}
.slide img {display: block; float: left; width: 640px; height: 290px; position: relative; top: -20px; left: -30px;}
.slide .post {padding: 20px 30px 0;}
.slide .post-category {font-size: 11px; color: #d9d9d9; text-transform: uppercase; margin-bottom: 5px;}
.slide .post a {color: #000;}
.slide .post .post-category a {text-decoration: none;}
.slide .post .post-category a:hover {text-decoration: underline;}
.slide .post h2 {margin-bottom: 5px;}
.slide .post h2, .slide .post h2 a {color: #000; font-size: 24px; font-weight: normal; text-decoration: none;}
.slide .post h2 a:hover {text-decoration: underline;}
.slide .post .post-meta {font-size: 11px; font-style: italic; color: #656363; margin-bottom: 20px;}
.slide .post .post-meta span, .slide .post .post-meta a {color: #000; text-decoration: none; font-family: Helvetica, Arial, sans-serif; font-style: normal;}
.slide .post .post-meta a:hover {text-decoration: underline;}
.slide .post .post-author {text-transform: uppercase;}
.slide .post-content p {margin-bottom: 15px;}
#larr, #rarr {display: block; width: 32px; height: 53px; position: absolute; top: 106px !important; opacity: 0.2; z-index: 99 !important;}
#larr {background: #000 url(“images/larr.png”) 8px 50% no-repeat; left: 0 !important;}
#rarr {background: #000 url(“images/rarr.png”) 11px 50% no-repeat; right: 0 !important;}
#larr:hover, #rarr:hover {opacity: 1;}

/*** Content ***/

#content {width: 640px; float: left;}

.content-title {color: #000; font-size: 18px; padding: 0 0 15px 30px; border-bottom: 1px solid #d9d9d9; text-transform: uppercase; position: relative;}
.content-title a {color: #000; text-decoration: none;}
.content-title a:hover {text-decoration: underline;}
.content-title span {color: #d9d9d9;}
.content-title span a {color: #d9d9d9; text-decoration: none;}
.content-title span a:hover {color: #000; text-decoration: none;}
#mode {display: block; width: 37px; height: 14px; background: url(“images/mode.png”) 0 0 no-repeat; position: absolute; bottom: 14px; right: 0;}
.flip {background-position: 0 100% !important;}

.list .post {padding: 30px 0 0 30px; border-bottom: 1px solid #d9d9d9;}
.list .post .thumb img {float: left; margin: 0 30px 30px 0; width: 290px; height: 290px;}
.list .post a {color: #000;}
.list .post .post-category {font-size: 11px; color: #d9d9d9; text-transform: uppercase; margin-bottom: 11px;}
.list .post .post-category a {text-decoration: none;}
.list .post .post-category a:hover {text-decoration: underline;}
.list .post h2 {margin-bottom: 8px;}
.list .post h2, .list .post h2 a {color: #000; font-size: 24px; font-weight: normal; text-decoration: none;}
.list .post h2 a:hover {text-decoration: underline;}
.list .post .post-meta {font-size: 11px; font-style: italic; color: #aaa9a9; margin-bottom: 20px;}
.list .post .post-meta span, .list .post .post-meta a {color: #000; text-decoration: none; font-family: Helvetica, Arial, sans-serif; font-style: normal;}
.list .post .post-meta a:hover {text-decoration: underline;}
.post-author {text-transform: uppercase;}

.grid {padding: 12px 0 0 12px;}
.grid .post {width: 154px; height: 154px; background-color: #f5f5f5; padding: 18px; float: left; margin: 19px 0 0 19px; position: relative; overflow: hidden; cursor: pointer;}
.grid .post .post-category, .grid .post .post-content, .grid .post .post-meta em {display: none;}
.grid .post h2, .grid .post .post-meta {display: block;}
.grid .post .thumb {width: 190px; height: 190px; position: absolute; top: 0; left: 0; z-index: 1;}
.grid .post .thumb img {width: 190px; height: 190px;}
.grid .post h2, .grid .post h2 a {color: #000; font-size: 16px; font-weight: normal; text-decoration: none;}
.grid .post h2 {margin-bottom: 5px;}
.grid .post a {text-decoration: none;}
.grid .post a:hover {text-decoration: underline;}
.grid .post .post-meta {font-size: 10px; font-style: italic; color: #656363;}
.grid .post .post-meta span, .grid .post .post-meta a {color: #000; font-family: Helvetica, Arial, sans-serif; font-style: normal;}
.grid .post .post-meta .post-author {text-transform: uppercase;}
.grid .post .comments_popup_link {position: absolute; bottom: 18px; right: 18px;}
.grid .post .post-edit-link {position: absolute; bottom: 18px; left: 18px;}

.rollover {opacity: 0; background: #ffea97; width: 154px; height: 154px; padding: 18px; margin: 0; position: absolute; top: 0; left: 0; cursor: pointer;}
.rollover-title {margin-bottom: 5px;}
.rollover-title, .rollover-title a {color: #000; font-size: 16px; font-weight: normal; text-decoration: none;}
.rollover-title a:hover {text-decoration: underline;}
.rollover-content {color: #262626; font: 12px/1.5 Helvetica, Arial, sans-serif;}
.rollover-meta {font-size: 10px; font-style: italic; color: #656363;}
.rollover-meta span, .rollover-meta a {color: #000; text-decoration: none; font-family: Helvetica, Arial, sans-serif; font-style: normal;}
.rollover-author {text-transform: uppercase;}
.rollover-meta a:hover {text-decoration: underline;}

.pagination {padding: 20px 0 0 30px; color: #aaa9a9; font-size: 12px; clear: both; position: relative;}
.pagination a {color: #000; text-decoration: none;}
.pagination a:hover {text-decoration: underline;}
.pagination .nextpostslink {position: absolute; right: 0; top: 17px; line-height: 21px; text-transform: uppercase; background: url(“images/nextpostslink.png”) 100% 0 no-repeat; padding-right: 36px;}
.pagination .previouspostslink {position: absolute; left: 30px; top: 17px; line-height: 21px; text-transform: uppercase; background: url(“images/previouspostslink.png”) 0 0 no-repeat; padding-left: 36px;}
#pagination {padding: 20px 0 0 30px;}
#pagination .nextpostslink {color: #000; text-decoration: none; display: block; padding: 9px 0; text-align: center; font-size: 14px;}
#pagination .nextpostslink:hover {background-color: #FFEA97; text-decoration: none; border-radius: 5px; -moz-border-radius: 5px; -webkit-border-radius: 5px;}
#pagination .loading {background: url(“images/loading.gif”) 240px 9px no-repeat; color: #555;}
#pagination .loading:hover {background-color: transparent !important; cursor: default;}

.entry {margin-bottom: 50px;}
.entry .post {border-bottom: 1px solid #d9d9d9; padding-bottom: 15px;}
.entry .post-meta {padding: 15px 0 15px 30px; border-bottom: 1px solid #d9d9d9; font-size: 11px; font-style: italic; color: #aaa9a9; position: relative;}
.entry .post-meta h1 {color: #333; font-size: 30px; font-weight: normal; font-style: normal; margin-bottom: 5px;}
.entry .post-meta span, .entry .post-meta a {color: #000; text-decoration: none; font-family: Helvetica, Arial, sans-serif; font-style: normal;}
.entry .post-meta a:hover {text-decoration: underline;}
.entry .post-comms {position: absolute; right: 0;}
.entry .post-content {padding: 15px 0 0 30px;}
.entry .post-content a {color: #000;}
.entry .post-content a:hover {text-decoration: none;}
.entry .post-footer {padding-left: 30px; font-size: 12px; margin-bottom: 15px;}
.entry .post-footer a {color: #000; text-decoration: none;}
.entry .post-footer a:hover {text-decoration: underline;}
.page .post-category {display: none;}

.f, .t, .di, .su {width: 16px; height: 15px; position: absolute; bottom: 15px;}
.f {right: 63px; background: url(“images/social.png”) 0 0 no-repeat;}
.t {right: 42px; background: url(“images/social.png”) -16px 0 no-repeat;}
.di {right: 21px; background: url(“images/social.png”) -32px 0 no-repeat;}
.su {right: 0; background: url(“images/social.png”) -48px 0 no-repeat;}
.f:hover {background-position: 0 -15px;}
.t:hover {background-position: -16px -15px;}
.di:hover {background-position: -32px -15px;}
.su:hover {background-position: -48px -15px;}

.post-content {margin-bottom: 30px;}
.post-content h1, .post-content h2, .post-content h3, .post-content h4, .post-content h5 {color: #000; font-weight: normal; font-family: Georgia, Geneva, “Times New Roman”, times; margin: 15px 0;}
.post-content h1 {font-size: 30px; line-height: 35px;}
.post-content h2 {font-size: 26px;}
.post-content h3 {font-size: 22px;}
.post-content h4 {font-size: 20px;}
.post-content h5 {font-size: 18px;}
.post-content {color: #262626; font: 12px/1.5 Helvetica, Arial, sans-serif;}
.post-content p {margin: 10px 0;}
.post-content ol {list-style: decimal; padding-left: 35px; margin: 15px 0;}
.post-content ul {list-style: disc; padding-left: 35px; margin: 15px 0;}
.post-content li {color: #262626; font: 12px/1.5 Helvetica, Arial, sans-serif; margin: 3px 0;}
.post-content blockquote {padding: 15px 0 10px 65px; background: url(“images/bq.png”) 20px 0 no-repeat;}
.post-content blockquote p {color: #8c8888; font: italic 16px Georgia, Geneva, “Times New Roman”, times;}

.post-content .search {float: none; margin-top: 15px; width: auto;}
.post-content .search fieldset {width: 610px; height: 35px;}
.post-content .search input {width: 570px; font-size: 16px;}

.post-navigation {width: 610px; padding: 15px 0 0 30px; position: relative;}
.post-navigation a {display: block; color: #000; font: 11px Helvetica, Arial, sans-serif; text-decoration: none; line-height: 1.5;}
.post-navigation a:hover {text-decoration: none;}
.post-navigation a em {display: block; color: #aaa9a9; font: italic 11px Georgia, Geneva, “Times New Roman”, times;}
.post-navigation a:hover span {text-decoration: underline;}
.post-prev {width: 250px; min-height: 40px; padding-left: 30px; float: left; text-align: left; background: url(“images/post_prev.png”) 0 50% no-repeat;}
.post-next {width: 250px; min-height: 40px; padding-right: 30px; float: right; text-align: right; background: url(“images/post_next.png”) 100% 50% no-repeat;}
.line {width: 1px; height: 100%; background: #d9d9d9; position: absolute; top: 0; right: 305px;}

/*** Images ***/

.post-content img {margin: 0 0 15px; height: auto; max-width: 610px;}
.post-content h6 {position: relative; left: -30px;}
.post-content .attachment img {max-width: 610px;}
.post-content .alignnone, .post-content img.alignnone {clear: both; display: block; margin-bottom: 15px;}
.post-content .alignleft, .post-content img.alignleft {display: inline; float: left; margin-right: 15px; margin-top: 4px;}
.post-content .alignright, .post-content img.alignright {display: inline; float: right; margin-left: 15px; margin-top: 4px;}
.post-content .aligncenter, .post-content img.aligncenter {clear: both; display: block; margin-left: auto; margin-right: auto;}
.post-content img.alignleft, .post-content img.alignright, .post-content img.aligncenter {margin-bottom: 15px;}
.post-content .wp-caption {background: #f1f1f1; line-height: 18px; margin-bottom: 20px; padding: 4px; text-align: center;}
.post-content .wp-caption img {margin: 5px 5px 0;}
.post-content .wp-caption p.wp-caption-text {color: #888; font-size: 12px; margin: 5px;}
.post-content .wp-smiley {margin: 0;}
.post-content .gallery {margin: 0 auto 18px;}
.post-content .gallery .gallery-item {float: left; margin-top: 0; text-align: center; width: 190px;}
.post-content .gallery .gallery-item img {max-width: 190px; border: none !important; margin-bottom: 0;}
.post-content .gallery .gallery-caption {color: #888; font-size: 12px; margin: 0 0 12px;}
.post-content .gallery dl {margin: 0;}
.post-content .gallery br+br {display: none;}
.post-content .attachment img {display: block; margin: 0 auto;}

/*** Comments ***/

.comments h3 {font-size: 18px; font-weight: normal; color: #000; padding: 15px 0 10px 30px; border-bottom: 1px solid #d9d9d9;}
.comments a {color: #000;}
#comments {margin-bottom: 30px;}
.comment {padding: 15px 0 15px 30px; border-bottom: 1px dotted #d9d9d9;}
.comment td {vertical-align: top;}
.comment-meta {position: relative; min-height: 70px; font-size: 11px; margin-right: 30px;}
.avatar {display: block; margin-right: 10px;}
.comment-author {color: #aaa9a9;}
.comment-author span {color: #000;}
.comment-author a, .comment-author span {text-decoration: none; text-transform: uppercase; font-family: Helvetica, Arial, sans-serif; font-style: normal;}
.comment-author a:hover {text-decoration: underline;}
.comment-author, .comment-date {white-space: nowrap;}
.comment-reply-link {position: absolute; bottom: 1px; text-decoration: none;}
.comment-reply-link:hover {text-decoration: underline;}
.comment-text p {color: #4b4b4b; ; font: 12px Helvetica, Arial, sans-serif; margin-bottom: 15px;}
.children {margin-left: 80px;}
.children .children {margin-left: 50px;}
.children .comment {padding-left: 0;}

#respond p, .nopassword {margin: 10px 0; font: 11px Helvetica, Arial, sans-serif;}
.nopassword {padding-left: 30px;}
#respond p a {text-decoration: none;}
#respond p a:hover {text-decoration: underline;}
#commentform {padding: 30px 0 0 30px;}
#commentform table {width: 100%; margin-bottom: 15px;}
#commentform td {vertical-align: top; width: 33.33%;}
#commentform td p {font: bold 11px Helvetica, Arial, sans-serif; color: #333; margin-bottom: 5px;}
#commentform td p span {color: #aaa9a9; font: italic 11px Georgia, Geneva, “Times New Roman”, times;}
.commform-textarea {border: 1px solid #d9d9d9; padding: 10px; margin-bottom: 10px;}
#comment {width: 100%; height: 120px; padding: 0; margin: 0; border: none; border-color: #fff; overflow: auto;}
.commform-author div {margin-right: 15px; border: 1px solid #d9d9d9; padding: 5px;}
.commform-email div {border: 1px solid #d9d9d9; padding: 5px;}
.commform-url p {margin-left: 15px !important;}
.commform-url div {margin-left: 15px; border: 1px solid #d9d9d9; padding: 5px;}
#author, #email, #url {width: 100%; margin: 0; padding: 0; border: none; font: 12px Helvetica, Arial, sans-serif; color: #333;}
#submit {float: left; border: none; background: #ccc; color: #fff; font: bold 12px Helvetica, Arial, sans-serif; cursor: pointer; padding: 5px 10px; border-radius: 3px; -moz-border-radius: 3px; -webkit-border-radius: 3px;}
#submit:hover {background: #000;}
p#cancel-comment-reply {float: right; line-height: 28px; margin: 0;}

/*** Sidebar ***/

.sidebar {width: 275px; padding: 4px 30px 0 0; float: right;}
.widget {margin-bottom: 35px;}
.widget-small {width: 130px;}
.widget h3, .widget-small h3 {color: #1f2122; font-size: 14px; font-weight: normal; text-transform: uppercase; padding-bottom: 15px; margin-bottom: 20px; border-bottom: 1px solid #d9d9d9;}
.widget a, .widget-small a {color: #000; text-decoration: none;}
.widget a:hover, .widget-small a:hover {text-decoration: underline;}
.widget p, .textwidget {color: #262626; font: 12px/1.3 Helvetica, Arial, sans-serif;}
.widget p a, .textwidget a {text-decoration: underline;}
.widget p a:hover, .textwidget a:hover {text-decoration: none;}
.widget li, .widget-small li {font-size: 12px; color: #262626; margin-bottom: 3px;}

.widget_getconnected {margin-bottom: 20px;}
.widget_getconnected .widget-body div {width: 50%; float: left; min-height: 40px; padding-bottom: 16px;}
.widget_getconnected .widget-body div a {display: block; color: #24211f; font-size: 16px; padding-left: 25px;}
.widget_getconnected .widget-body div span {color: #838383; font: 11px Helvetica, Arial, sans-serif; padding-left: 25px;}
.getconnected_rss a {background: url(“images/getconnected_rss.png”) 0 2px no-repeat;}
.getconnected_twitter a {background: url(“images/getconnected_twitter.png”) 0 2px no-repeat;}
.getconnected_fb a {background: url(“images/getconnected_fb.png”) 0 2px no-repeat;}
.getconnected_flickr a {background: url(“images/getconnected_flickr.png”) 0 2px no-repeat;}
.getconnected_behance a {background: url(“images/getconnected_behance.png”) 0 2px no-repeat;}
.getconnected_delicious a {background: url(“images/getconnected_delicious.png”) 0 2px no-repeat;}
.getconnected_stumbleupon a {background: url(“images/getconnected_stumbleupon.png”) 0 2px no-repeat;}
.getconnected_tumblr a {background: url(“images/getconnected_tumblr.png”) 0 2px no-repeat;}
.getconnected_vimeo a {background: url(“images/getconnected_vimeo.png”) 0 2px no-repeat;}
.getconnected_youtube a {background: url(“images/getconnected_youtube.png”) 0 2px no-repeat;}

.rpthumb {display: block; padding-bottom: 15px; margin-top: 15px; border-bottom: 1px dotted #d9d9d9;}
.rpthumb img {width: 50px; width: 50px; margin-right: 15px; float: left;}
.rpthumb-title {display: block; font: 12px Georgia, Geneva, “Times New Roman”, times; margin-bottom: 6px;}
.rpthumb-date {display: block; font-size: 11px; color: #aaa9a9;}
.rpthumb:hover {text-decoration: none !important;}
.rpthumb:hover .rpthumb-title {text-decoration: underline;}

.widget_tag_cloud a {margin: 0 2px;}
.widget_calendar table {width: 100%;}
.widget_calendar caption {font-size: 13px; padding-bottom: 10px; text-align: left;}
.widget_calendar th, .widget_calendar td {padding: 5px 0; font-size: 13px;}
.widget_calendar tbody a {text-decoration: underline;}
.widget_calendar tbody a:hover {text-decoration: none}

.sponsors .widget-body {text-align: center;}
.sponsors .widget-body img {margin-bottom: 20px;}

/*** Footer ***/

.footer {height: 60px; border-top: 1px solid #d9d9d9; padding: 20px 30px 0;}
.footer p {font-size: 12px; color: #737373;}
.footer a {color: #000; text-decoration: none;}
.footer a:hover {text-decoration: underline;}
p.copyright {float: left; color: #333;}
p.copyright span {color: #737373;}
.credits {float: right;}