Example of styling the text in a Spinitron "now playing" iframe. Description is in a comment below.

nowplaying.html

<!DOCTYPE html>
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
    <title>Spinitron Playlists</title>
</head>
<body>
    <p class="recentsong">
        <span class="songpart"><b>Wave Guidance Allows Three</b></span>
        <span class="artistpart">by <b><a target="_top" href="/public/index.php?station=wzbc&amp;dbdetail=a&amp;dbid=83733">The Swifter</a></b></span>
        <span class="diskpart">from <b><a target="_top" href="/public/index.php?station=wzbc&amp;dbdetail=d&amp;dbid=190343">The Swifter</a></b></span>
        <span class="labelpart">(<b><a target="_top" href="/public/index.php?station=wzbc&amp;dbdetail=l&amp;dbid=30332">The Wormhole</a></b>)</span>
        <span class="spunpart">spun 
          <span class="djpart">by <span><a target="_top" href="/public/index.php?station=wzbc&amp;djuid=169">Saul</a></span></span>
          <span class="timepart">at <span>9:10pm</span></span>
          <span class="playlistpart">on 
              <a target="_top" href="/public/index.php?station=wzbc&amp;plid=23621"><span class="showname">Fat's Superhead & the 68 Year Old Man </span>
              <span class="datepart">(Tue Mar 5th)</span></a>
      	  </span>
        </span>
    </p>
</body>
</html>

styles.css

body {
    color: #bbb;
    background: black;
    font-family: sans-serif;
    font-size: 12px;
    line-height: 16px;
    }
p.recentsong b {
    font-weight: bold;
    color: white;
    }
p.recentsong a {
    color: #ff8000;
    }
p.recentsong span.songpart {
    font-style: italic;
    }
p.recentsong span.labelpart,
p.recentsong span.djpart,
p.recentsong span.datepart{
    display: none;
    }

The nowplaying.html file above is an example of a page from http://spinitron.com/public/newestsong.php?station=wzbc which you could use as the src url of an <iframe>. But you probably want to style it differently. styles.css demonstrates some style rules you could use with the html.

Admin users can save a stylesheet in Spinitron (Admin menu: CSS Stylesheet) or anyone may keep a stylesheet on some other server. To use a stylesheet stored in Spinitron, add &css=true to the iframe's src url:

http://spinitron.com/public/newestsong.php?station=wzbc&css=true

If it is elsewhere then add instead &stylesheet= followed by the url-encoed url to the stylesheet:

http://spinitron.com/public/newestsong.php?station=wzbc&stylesheet=http%3A%2F%2Fexample.com%2Fstyles.css

in which http%3A%2F%2Fexample.com%2Fstyles.css is just an example, it is the url-encoded value for http://example.com/styles.css.