Add colored content boxes to any theme. Source: http://www.studiopress.com/design/colored-content-boxes-buttons.htm

add-colored-content-boxes.css

/* Colored content boxes */

.content-box-blue,
.content-box-gray,
.content-box-green,
.content-box-purple,
.content-box-red,
.content-box-yellow {
    margin: 0 0 25px;
    overflow: hidden;
    padding: 20px;
}

.content-box-blue {
    background-color: #d8ecf7;
    border: 1px solid #afcde3;
}

.content-box-gray {
    background-color: #e2e2e2;
    border: 1px solid #bdbdbd;
}

.content-box-green {
    background-color: #d9edc2;
    border: 1px solid #b2ce96;
}

.content-box-purple {
    background-color: #e2e2f9;
    border: 1px solid #bebde9;
}

.content-box-red {
    background-color: #f9dbdb;
    border: 1px solid #e9b3b3;
}

.content-box-yellow {
    background-color: #fef5c4;
    border: 1px solid #fadf98;
}

colored-content-box.html

<div class="content-box-blue">Enter content box text here.</div>