Japanese input method does not work with Nord color theme

### Checklist

- [x] Using latest version on TestFlight
- [x] Read the [docs](http://blink.sh/docs/)
- [x] Searched for [existing GitHub issues](https://github.com/blinksh/blink/issues)

### Configuration

Blink version: v18.1.1.977 (TestFlight)
iOS version: iPadOS 18.3.1

### Describe the bug

What's happening:
1. Install the Nord theme with the name "Nord Original" from https://raw.githubusercontent.com/blinksh/themes/refs/heads/master/themes/Nord.js.
2. Install the MaterialDarker theme with the name "MaterialDarker Original" from https://raw.githubusercontent.com/blinksh/themes/refs/heads/master/themes/MaterialDarker.js.
3. Open 3 tabs with each of the Default, Nord and MaterialDarker themes.
4. Switch to iOS's built-in Japanese – Kana input.
5. Attempt to type some Japanese, e.g. `a a a `.
6. Only the Default-and-MaterialDarker-themed tabs accept the input.

Expected behavior: Japanese input method works correctly regardless of the theme chosen.

Start by reproducing the issue on iPadOS with iOS's Japanese–Kana input, using the Nord.js and MaterialDarker.js themes from the URLs in the report alongside the Default theme. Compare the three tabs while entering `a a a `; done means Japanese input works in the Nord-themed tab as it already does in the other themes.

Written by the indexing model from the issue text.