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What I’m trying to do
Things I have tried
i want to know how to prevent circled characters like ① from getting bigger by itself in obsidian.
please help me 
What’s your OS, custom font(s) if you’re set any, and your language input method?
On iOS, in a new vault and using the default / system font with this: ① ② ③ ④ ⑤ (entered using Japanese - Kana input), I see:
Live Preview:
Reading view:
Desktop Sandbox (both Live Preview and Reading modes) with the macOS system font (San Francisco, I believe):
But using any, for example, of the fonts here will give me the larger characters:
You could try playing around with different fonts or different unicode characters to get the look you’d like.