[Feature]: 能不能加一个调节字体大小的功能

[W-reverse]

Affected area

Frontend / UI

Problem or use case

目前的字体大小（无论是对话中的，还是ui的），在电脑端和手机端看着都有点费劲啊

Proposed behavior

希望添加字体大小调节功能

Alternatives considered

No response

Compatibility, deployment, or migration impact

No response

Documentation or API contract impact

No response

Pre-submit checklist

• I searched existing issues and pull requests.
• This request is focused on one feature or improvement.
• I described user-facing, API, configuration, or deployment impact where relevant.