In the WordPress Theme ad a custom_style.css file and do following changes to post background and text colors:
/*******************************************
GENERAL STYLING
*******************************************/
body {
background: #0d1424 url(images/body-bg.jpg) no-repeat center top;
font: .81em/150% "Lucida Grande", Arial, "Lucida Sans Unicode", sans-serif;
word-wrap: break-word;
color: #666;
/* Text color */
}
.
.
.
.
/*******************************************
STRUCTURE
*******************************************/
#pagewrap {
width: 978px;
margin: 0 auto;
}
/* content */
#content {
width: 600px;
float: left;
background: #000;
/* Background color */
padding: 35px;
margin-bottom: 10px;
border-radius: 8px;
box-shadow: 0 1px 3px rgba(0,0,0,.4);