plugin/upgrade/style.css

#plugin__upgrade {
    margin: 0 auto;
    height: 20em;
    overflow: auto;
}

#plugin__upgrade_form {
    display: block;
    margin: 0 auto 3em auto;
    width: 20em;
}

#plugin__upgrade_form input.continue {
    float: right;
}

#plugin__upgrade_form input.abort {
    float: left;
}

/* based on http://cssdeck.com/labs/progress-bar */

#plugin__upgrade_meter {
    height: 20px;
    position: relative;
    margin: 1em;
}

#plugin__upgrade_meter ol {
    margin: 0;
    padding: 0;
    display: block;
    height: 100%;
    width: 99%;
    border-radius: 10px;
    background-color: #ddd;
    position: relative;
    list-style: none;
}
#plugin__upgrade_meter ol li {
    float: left;
    margin: 0;
    padding: 0;
    text-align: right;
    width: 19%;
    position: relative;
    border-radius: 10px;
}

#plugin__upgrade_meter ol li span{
    right:-0.5em;
    display: block;
    text-align: center;
}
#plugin__upgrade_meter ol li .step {
    top: -0.4em;
    padding: .2em 0;
    border: 3px solid #ddd;
    z-index: 99;
    font-size: 1.25em;
    color: #ddd;
    width: 1.5em;
    font-weight: 700;
    position: absolute;
    background-color: #fff;
    border-radius: 50%;
}
#plugin__upgrade_meter ol li .stage {
    color: #fff;
    font-weight: 700;
}

#plugin__upgrade_meter ol li.active {
    height: 20px;
    background: #aaa;
}

#plugin__upgrade_meter ol li.active span.stage {
    color: #000;
}

#plugin__upgrade_meter ol li.active span.step{
    color: #000;
    border: 3px solid __link__;
}