Fix style when applying dark mode

[MtBlue81]

Problem

Difficult to see due to light mode highlight color applied in dark mode.

Solution

Apply dark mode style removed by #249

[h13i32maru]

Thanks!

[yosuke-oka]

This issue is still occurring in 1.1.2 😢

[MtBlue81]

@yosuke-oka
Is the environment GHE or something else?
I only checked in GitHub.com (on Mac Monterey) environment, sorry.

[yosuke-oka]

@MtBlue81
No. In github.com (private repo) on Mac Monterey environment...