Xmind for Android supports updating the styles to all topics by one click. When the style of a topic is edited, like text, color, branch color, etc., you can update the style to all subtopics, or subtopics at the same level.
1) Select a subtopic,
2) Tap ,
3) Tap ,
4) Edit the style of the topic,
5) Slide down and you can find the button of Update Style,
6) Tap Update Style,
7) Tap Update to All Subtopics or Update to All Level X Topics.