More precise background to allow easy RTL flipping

This is supposed to fix the following downstream bug:
https://bugzilla.wikimedia.org/show_bug.cgi?id=49317
Making the value closer to the original
Merge pull request #184 from amire80/bug-49317

More precise background to allow easy RTL flipping
Correct my language name in input method names

Use မြန်မာဘာသာ
Retain a little transparency for the IME selector

see https://bugzilla.wikimedia.org/show_bug.cgi?id=49317