Here is a color palette based on your request for a dark theme with the primary color #3498DB and a background color of #1B1B1B :

json
{
  "palette_name": "Dark Theme with Blue Accents",
  "colors": [
    {
      "name": "Primary Blue",
      "hex_code": "
          
          #3498DB
       "
    },
    {
      "name": "Background Black",
      "hex_code": "
          
          #1B1B1B
       "
    },
    {
      "name": "Accent Gray",
      "hex_code": "
          
          #2C2C2C
       "
    },
    {
      "name": "Text White",
      "hex_code": "
          
          #FFFFFF
       "
    },
    {
      "name": "Highlight Blue",
      "hex_code": "
          
          #1ABC9C
       "
    }
  ]
}

This palette combines the primary blue with a dark background and additional complementary colors to enhance a dark theme.

Would you like any specific suggestions on how to use this palette, or do you have any other requests?