Add more opacity to admin region in the front page

[Info 3bits]

The admin area is not visible with dark background

Text included.

Add more opacity and text-shadow to the text

[Jeremy Hopkins]

shall we add settigns for this rather than hard code it? Maybe:

1) Color 2) Opacity

Then it will work on any site

[Info 3bits]

fix #749 admin region opacity

→ <<cset 32f727c8efe9>>

[Info 3bits]

No, just added 50% wich is well displayed in dark and light backgrounds and changed the text color to red with a white shadow for dark backgrounds.

tested with black, white and a dark image and loks well now