Fix the styling of the accessibility dialog

It’s not perfect but comes close to the appearance of our dialogs.

See https://www.woltlab.com/community/thread/307927-ckeditor-hilfefenster-schrift-im-dunklen-farbschema-kaum-lesbar-layout-schief/

wcfsetup/install/files/style/ui/ckeditor.scss

@@ -662,3 +662,25 @@ html.iOS {
 		display: none !important;
 	}
 }
+
+/* Accessiblity Dialog */
+.ck.ck-dialog {
+	--ck-accessibility-help-dialog-border-color: var(--wcfContentBorderInner);
+	--ck-color-dialog-form-header-border: var(--wcfContentBorderInner);
+	--ck-accessibility-help-dialog-code-background-color: transparent;
+
+	background-color: var(--wcfContentBackground);
+	border-radius: var(--wcfBorderRadiusContainer);
+	box-shadow: var(--wcfBoxShadow);
+	color: var(--wcfContentText);
+
+	dl:not(.plain) {
+		&:not(:first-child) {
+			margin-top: 0;
+		}
+
+		> :is(dt:not(:empty), dd:not(:last-child)) {
+			margin-bottom: 0;
+		}
+	}
+}