Here is a color palette based on your specifications for a dark theme:

json
{
  "palette_name": "Dark Theme Palette",
  "colors": [
    {
      "name": "Primary Blue",
      "hex_code": "
                            
                            #3498DB
                        "
    },
    {
      "name": "Secondary Purple",
      "hex_code": "
                            
                            #673AB7
                        "
    },
    {
      "name": "Background Dark",
      "hex_code": "
                            
                            #1B1B1B
                        "
    }
  ]
}

This palette features a vibrant primary blue and a rich secondary purple against a deep dark background, creating a striking contrast that is perfect for a dark-themed design.

Would you like to explore additional color options or modifications for this palette?