useStyle method
Implementation
void useStyle(NikuTextStyle Function(NikuTextStyle) v) {
if (titleTextStyle == null) titleTextStyle = NikuTextStyle();
titleTextStyle?.apply = v(titleTextStyle!);
}
void useStyle(NikuTextStyle Function(NikuTextStyle) v) {
if (titleTextStyle == null) titleTextStyle = NikuTextStyle();
titleTextStyle?.apply = v(titleTextStyle!);
}