Change Widget Title Size

Hi Yigit! Thanks for your quick reply. Unfortunately that didn’t work. Any ideas? Here’s what I have under the custom css box. Maybe there’s something blocking it from working?

.content { padding-top: 10px; }
#top .title_container .container { padding: 0; min-height: 36px; }
.social_header .phone-info span { font-size: 18px; }
#header_main .container { height: 150px!important; line-height:150px!important; }
.social_header .main_menu ul:first-child > li a { height: 90px; }
.iphorm-element-spacer { padding-bottom: 0; }
#header_meta { display: none; }
.logo img { padding: 15px 0; }
.main_menu { top: 11%; }

#top #menu-item-search { display: none; }
.main_menu ul:first-child > li > a { font-size: 15px; }
.sidebar { padding-top: 25px; }
h3.widgettitle { font-size: 15px; color: #2a3032; }
.widget_nav_menu a { font-size: 14px!important; color: #2a3032 !important; }
#top .widget_nav_menu ul ul li a { padding: 2px 0px 3px 12px; }
.main_color strong { color: #333333; }

.header_color .main_menu ul:first-child > li > a, h1, h2, h3, h4, h5, h6 { font-family: Helvetica, Arial, sans-serif !important; }
.widget h1, .widget h2, .widget h3, .widget h4, .widget h5, .widget h6 { text-transform:capitalize!important; }
.widget a, .widget p { color: #333333 !important; }

.main_color h3.widgettitle { font-weight: bold; color: #ce1433; }

.widgettitle { font-size: 24px; }