We're going to supply an additional CSS module to our UI—one that overrides the accordion structure supplied in the theme we happen to be using. There's no need to fret, however, our change is a simple one. We're going to update the margin-top property. In a new CSS file called theme.accordion.css, let's add the following style rules:

.ui-accordion .ui-accordion-header {
    margin-top: 4px;
}

Now that we have the CSS, we need to include it in our HTML header. It should look something like this:

We're copying the same CSS selector as is found in any jQuery UI theme. The particular property we've just changed alters the space between the accordion sections. Since we're overriding the default theme value, it's important to include our CSS files after the default theme file. This allows us to override the default theme instead of the default theme overriding our modifications.