gpgme/lang/js/DemoExtension/ui.css

ul {
    list-style-type: none;
    padding-left: 0px;
}

ul li span {
    float: left;
    width: 120px;
    margin-top: 6px;
}

div .left {
    float: left;
    align-items: stretch;
    width: 40%;
}
div .center {
    width: 50%;
    align-content: space-between;
}

div .center button {
    align-self: stretch;
}
div .right {
    float: right;
    align-items: stretch;
    width: 40%;
}

div .bottom {
    clear:both;
}