* Create dark-style.css
* Add call to get_color_scheme
* Add call to get_color_scheme
* Create get_color_scheme function
* Add selection box in config.php
* Accept both lower and uppercase COLOR_SCHEME
* Add COLOR_SCHEME
* Add COLOR_SCHEME
* Change birdnet.conf after color scheme selection
* Move css to static to enable it
* Adapt css location to static
* Improve opacity value
* Fix logo background issues on smaller screens
* Avoid overlap of logos
* Ensure clean look (same margin as before but different location)
* Default background as transparent to avoid white on white
* Avoid black on dark ; improve readability
* Last element of green is homogenized to grayscale
* Enable site reload after color_scheme change
Alexandre