#### What type of PR is this?
/area ui
/kind improvement
/milestone 2.13.0
#### What this PR does / why we need it:
优化登录相关页面的布局，修复在不同分辨率下的样式问题。
#### Which issue(s) this PR fixes:
Fixes https://github.com/halo-dev/halo/issues/5346
#### Special notes for your reviewer:
测试登录或者注册页面，任意放大或者缩小页面，观察页面样式是否正常。
#### Does this PR introduce a user-facing change?
```release-note
优化登录相关页面的布局，修复在不同分辨率下的样式问题。
```
Ryan Wang