Make TTS control buttons more contrast

[Korb]

Currently, the blue buttons "Rewind", "Play / Pause", "Fast forward" and "Close" are displayed in color 0961ba, which is difficult to see on an AMOLED screen at maximum brightness, dark application theme, black background and in sunny weather. The same with the minimum brightness of the screen in almost complete darkness.

I suggest making these icons two-color, with contrasting borders, so that they are equally distinguishable in bright light, both in a light application theme and in a dark one.

[foobnix]

please check beta.librera.mobi, you can also change the accent color of the buttons

[foobnix]