style: dark/light mode transition duration for switch doesn't match page transition duration

[kevinzunigacuellar]

Describe the bug

When switching between dark and light modes, the background color transition of the switch is longer than the rest of the page.

Recording

theme-flick.mov

• I would like to submit a PR for this issue

Reproduction

1. Go to VitePress
2. Click on the dark/light mode switch multiple times
3. Notice the flash between the background color of the switch with the rest of the page

Expected behavior

Screen.Recording.2022-10-13.at.17.59.54.mov

System Info

System:
    OS: macOS 12.6
    CPU: (8) arm64 Apple M1 Pro
    Memory: 542.95 MB / 16.00 GB
    Shell: 5.8.1 - /bin/zsh
  Binaries:
    Node: 18.10.0 - /opt/homebrew/bin/node
    npm: 8.19.2 - /opt/homebrew/bin/npm
  Browsers:
    Chrome: 106.0.5249.119
    Firefox: 105.0.3
    Safari: 16.0

Additional context

No response

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