Dark mode for Help, and few minor errors

[gmb]

Is it possible to implement dark mode for help files? That's only not dark part of the app.

Also, there are few minor errors in HTML files...

I was experimenting with dark mode, added body, a {background-color:#000; color:#fff;} above </style>, and one paragraph disappeared (black letters on black background).
In line 564 in EN, and line 563 in CS and ES file, opening tag <p> is missing.
And in line 563 in RU and UK file, opening tag <p> is missing, but also closing tag </p> in the line above.

In CS file, line 902, alt=height="32" should be height="32"
and in DE file, line 572, first </B> should be <B>.

If you will consider dark mode for Help, note that playback_speed.png is invisible in dark mode because of alpha transparency.

[ghisler(Author)]

I will consider it, thanks for your suggestion and for your corrections.