gistfile1.css

.spoiler {
    display: block;
    width: 200px;
    border: #ccc solid 1px;
}
.spoiler > .title {
    display: block;
    padding: 4px;
}
.spoiler > .body {
    padding: 4px;
    border-top: #ccc solid 1px;
    display: none;
}
.spoiler > :checked ~ .body {
    display: block;
}