Bad character escape sequence, expected 2 hex characters in Layout.less

[iliya03]

What happens?

When I build the project with umi 4.5.3 and antd 6 on linux, it runs fine, but on windows, I get the following issue:

Building with mako for development...
● Mako ▨▨▨▨▨▨▨▨▨▨▨▨▨▨▨▨▨▨▨▨▨▨▨▨▨ (24%) parse parse                                                                                                          Build failed.
  × Bad character escape sequence, expected 2 hex characters
    ╭─[src/.umi/plugin-layout/Layout.less:38:1]
 35 │ undefined
 36 │
 37 │
 38 │       Error in \Users\iliya\Projects\xenlogix-new\fe\src\.umi\plugin-layout\Layout.less (line 1, column 0).`)
    ·                                     ───
    ╰────

fatal - [Error: Build with mako failed.]
fatal - A complete log of this run can be found in:
fatal - C:\Users\iliya\Projects\xenlogix-new\fe\node_modules\.cache\logger\umi.log
fatal - Consider reporting a GitHub issue on https://github.com/umijs/umi/issues

How To Reproduce

Steps to reproduce the behavior:

1. upgrade from antd 5 to 6
2. Set antd: { import: false, style: 'css' } in config.ts
3. Run pnpm i and pnpm dev

Expected behavior

1. Program runs successfully

Context

• Umi Version: 4.5.3
• Node Version: 22.14.0
• Platform: Windows x86_64