Wikipedia:Twinkle/Preferences/styles.css

/* Twinkle config */
#twinkle-config {
	border: 1px solid #666;
	background: var(--twinkle-bgcolor-dialog, #F0F8FF);
	color: inherit;
}

#twinkle-config label {
	color: var(--color-base, #202122);
}

#twinkle-config-titlebar {
	background: var(--twinkle-bgcolor-titlebar, #BCCADF);
	color: inherit;
}

#twinkle-config-buttonpane {
	background: var(--twinkle-bgcolor-titlebar, #BCCADF);
	color: inherit;
	padding: 0.5em;
}