Problem with subtitles

1. All the subtitles (h2-h6 tags) are really big size. The post title which is in h1 looks roughly like text in h6.

I made an image but I didn’t find how to insert it here.

2. Title on the attachment page (which is in h1 tag) – I don’t use them much, but I think it’s part of the same problem – is too big.

Questions:
1. How do I fix it now?
2. Are you going to include the fix in next theme’s update?