fix: mkdocs.yml

# Theme

theme:

  name: null

  custom_dir: 'mkdocs-material/material'

  static_templates:

    - 404.html

  name: 'material'

  language: 'zh'

  palette:

    primary: 'white'

    accent: 'red'

  include_search_page: false

  search_index_only: true