Alter Welcome Screen colours for readability

I would like to suggest the following colour changes to FlatLaf Light and Dark for the Welcome Screen:

FlatLaf - Change background colour (instead of altering the image just for this theme) to make the logo stand out.

Current:

Suggested:

FlatLafDark - use actual dark image asset colours for content banner in order to avoid title "cutting".

Current:

Suggested:

 In addition, the default date color may be changed from orange to dark red (icon color) to improve consistency and readability, especially with Motif theme.

Current:

Suggested: