Colors of "action dropdown" ui are bad-contrast when using light theme.

[tSU-RooT]

Expected behavior

Colors of "action dropdown" ui are same as normal theme.

Actual behavior

These are bad-contrast for unknown reason.

Steps to reproduce

1. Set site theme "Mastodon (light)" from "Settings -> Preference"
2. Click "more" button on any toot ui.

NOTE

It's not reproduce on vanilla version of mastodon 2.6.1 and 2.7.3 as far as I know.

[rinsuki]

related: #199 #172