Template:IRC/styles.css

.irc-connect > a { color: green }

/* forced night mode */
html.skin-theme-clientpref-night .irc-connect > a { color: #12c812; }
@media (prefers-color-scheme: dark) {
    /* automatic mode */
    html.skin-theme-clientpref-os .irc-connect > a { color: #12c812; }
}