Here is a color palette based on your request for a dark blue theme without purple colors:

json
{
  "palette_name": "Deep Blue Serenity",
  "colors": [
    {
      "name": "Midnight Blue",
      "hex_code": "
                            
                            #001F3F
                        "
    },
    {
      "name": "Navy Blue",
      "hex_code": "
                            
                            #003366
                        "
    },
    {
      "name": "Sky Blue",
      "hex_code": "
                            
                            #007BFF
                        "
    },
    {
      "name": "Steel Blue",
      "hex_code": "
                            
                            #4682B4
                        "
    },
    {
      "name": "Light Blue",
      "hex_code": "
                            
                            #ADD8E6
                        "
    }
  ]
}

This palette consists of various shades of blue, providing a cohesive and calming aesthetic suitable for a web application. The darker tones create a strong visual foundation, while the lighter hues add contrast and can be used for highlights or accents.

Would you like to explore different shades or perhaps add some complementary colors?