OrganonTweaks/Template/layout/done_style.php

<?php
/**
 * Done/Due badge styling (emitted into the head when the feature is enabled). NATURAL document flow --
 * the badge renders above the title (board card) or as a list item (task view); no absolute
 * positioning, so it adapts to any card / column / avatar / username size. Two states via .is-done:
 * Due = black filled box + black text on a light red (#ef9a9a); Done = checked box, black on light
 * green (#a5d6a7). Both states use black text (core's `.task-board a { color:#000 }` forces the icon
 * black anyway, so the backgrounds are kept light for contrast). Colors are tunable.
 */
?>
<style>
span.organontweaks-done a {
    display: inline-block;
    text-decoration: none;
    padding: 3px 10px;
    border-radius: 3px;
    background: #ef9a9a;
    color: #000;
    font-weight: bold;
}
span.organontweaks-done.is-done a {
    background: #a5d6a7;
    color: #000;
}
.organontweaks-done {
    display: inline-block;
    margin: 1px 0;
}
</style>